From 0dedc1c573ddc4e87475eb03c64555cd54a72e92 Mon Sep 17 00:00:00 2001
From: Trevor Gamblin <trevor.gamblin@windriver.com>
Date: Mon, 7 Jun 2021 09:40:20 -0400
Subject: [PATCH] Fix imports for tests

Signed-off-by: Trevor Gamblin <trevor.gamblin@windriver.com>
---
 tests/test_asyncio.py              | 2 +-
 tests/test_asyncio_context_vars.py | 2 +-
 tests/test_functionality.py        | 2 +-
 tests/test_hooks.py                | 2 +-
 tests/test_tags.py                 | 2 +-
 5 files changed, 6 insertions(+), 6 deletions(-)

--- a/tests/test_asyncio.py
+++ b/tests/test_asyncio.py
@@ -2,7 +2,7 @@ import unittest
 import yappi
 import asyncio
 import threading
-from utils import YappiUnitTestCase, find_stat_by_name, burn_cpu, burn_io
+from .utils import YappiUnitTestCase, find_stat_by_name, burn_cpu, burn_io
 
 
 async def async_sleep(sec):
--- a/tests/test_asyncio_context_vars.py
+++ b/tests/test_asyncio_context_vars.py
@@ -5,7 +5,7 @@ import contextvars
 import functools
 import time
 import os
-import utils
+import tests.utils as utils
 import yappi
 
 async_context_id = contextvars.ContextVar('async_context_id')
--- a/tests/test_functionality.py
+++ b/tests/test_functionality.py
@@ -1,1916 +1,1916 @@
-import os
-import sys
-import time
-import threading
-import unittest
-import yappi
-import _yappi
-import utils
-import multiprocessing  # added to fix http://bugs.python.org/issue15881 for > Py2.6
-import subprocess
-
-_counter = 0
-
-
-class BasicUsage(utils.YappiUnitTestCase):
-
-    def test_callback_function_int_return_overflow(self):
-        # this test is just here to check if any errors are generated, as the err
-        # is printed in C side, I did not include it here. THere are ways to test
-        # this deterministically, I did not bother
-        import ctypes
-
-        def _unsigned_overflow_margin():
-            return 2**(ctypes.sizeof(ctypes.c_void_p) * 8) - 1
-
-        def foo():
-            pass
-
-        #with utils.captured_output() as (out, err):
-        yappi.set_context_id_callback(_unsigned_overflow_margin)
-        yappi.set_tag_callback(_unsigned_overflow_margin)
-        yappi.start()
-        foo()
-
-    def test_issue60(self):
-
-        def foo():
-            buf = bytearray()
-            buf += b't' * 200
-            view = memoryview(buf)[10:]
-            view = view.tobytes()
-            del buf[:10]  # this throws exception
-            return view
-
-        yappi.start(builtins=True)
-        foo()
-        self.assertTrue(
-            len(
-                yappi.get_func_stats(
-                    filter_callback=lambda x: yappi.
-                    func_matches(x, [memoryview.tobytes])
-                )
-            ) > 0
-        )
-        yappi.stop()
-
-    def test_issue54(self):
-
-        def _tag_cbk():
-            global _counter
-            _counter += 1
-            return _counter
-
-        def a():
-            pass
-
-        def b():
-            pass
-
-        yappi.set_tag_callback(_tag_cbk)
-        yappi.start()
-        a()
-        a()
-        a()
-        yappi.stop()
-        stats = yappi.get_func_stats()
-        self.assertEqual(stats.pop().ncall, 3)  # aggregated if no tag is given
-        stats = yappi.get_func_stats(tag=1)
-
-        for i in range(1, 3):
-            stats = yappi.get_func_stats(tag=i)
-            stats = yappi.get_func_stats(
-                tag=i, filter_callback=lambda x: yappi.func_matches(x, [a])
-            )
-
-            stat = stats.pop()
-            self.assertEqual(stat.ncall, 1)
-
-        yappi.set_tag_callback(None)
-        yappi.clear_stats()
-        yappi.start()
-        b()
-        b()
-        stats = yappi.get_func_stats()
-        self.assertEqual(len(stats), 1)
-        stat = stats.pop()
-        self.assertEqual(stat.ncall, 2)
-
-    def test_filter(self):
-
-        def a():
-            pass
-
-        def b():
-            a()
-
-        def c():
-            b()
-
-        _TCOUNT = 5
-
-        ts = []
-        yappi.start()
-        for i in range(_TCOUNT):
-            t = threading.Thread(target=c)
-            t.start()
-            ts.append(t)
-
-        for t in ts:
-            t.join()
-
-        yappi.stop()
-
-        ctx_ids = []
-        for tstat in yappi.get_thread_stats():
-            if tstat.name == '_MainThread':
-                main_ctx_id = tstat.id
-            else:
-                ctx_ids.append(tstat.id)
-
-        fstats = yappi.get_func_stats(filter={"ctx_id": 9})
-        self.assertTrue(fstats.empty())
-        fstats = yappi.get_func_stats(
-            filter={
-                "ctx_id": main_ctx_id,
-                "name": "c"
-            }
-        )  # main thread
-        self.assertTrue(fstats.empty())
-
-        for i in ctx_ids:
-            fstats = yappi.get_func_stats(
-                filter={
-                    "ctx_id": i,
-                    "name": "a",
-                    "ncall": 1
-                }
-            )
-            self.assertEqual(fstats.pop().ncall, 1)
-            fstats = yappi.get_func_stats(filter={"ctx_id": i, "name": "b"})
-            self.assertEqual(fstats.pop().ncall, 1)
-            fstats = yappi.get_func_stats(filter={"ctx_id": i, "name": "c"})
-            self.assertEqual(fstats.pop().ncall, 1)
-
-        yappi.clear_stats()
-        yappi.start(builtins=True)
-        time.sleep(0.1)
-        yappi.stop()
-        fstats = yappi.get_func_stats(filter={"module": "time"})
-        self.assertEqual(len(fstats), 1)
-
-        # invalid filters`
-        self.assertRaises(
-            Exception, yappi.get_func_stats, filter={'tag': "sss"}
-        )
-        self.assertRaises(
-            Exception, yappi.get_func_stats, filter={'ctx_id': "None"}
-        )
-
-    def test_filter_callback(self):
-
-        def a():
-            time.sleep(0.1)
-
-        def b():
-            a()
-
-        def c():
-            pass
-
-        def d():
-            pass
-
-        yappi.set_clock_type("wall")
-        yappi.start(builtins=True)
-        a()
-        b()
-        c()
-        d()
-        stats = yappi.get_func_stats(
-            filter_callback=lambda x: yappi.func_matches(x, [a, b])
-        )
-        #stats.print_all()
-        r1 = '''
-        tests/test_functionality.py:98 a      2      0.000000  0.200350  0.100175
-        tests/test_functionality.py:101 b     1      0.000000  0.120000  0.100197
-        '''
-        self.assert_traces_almost_equal(r1, stats)
-        self.assertEqual(len(stats), 2)
-        stats = yappi.get_func_stats(
-            filter_callback=lambda x: yappi.
-            module_matches(x, [sys.modules[__name__]])
-        )
-        r1 = '''
-        tests/test_functionality.py:98 a      2      0.000000  0.230130  0.115065
-        tests/test_functionality.py:101 b     1      0.000000  0.120000  0.109011
-        tests/test_functionality.py:104 c     1      0.000000  0.000002  0.000002
-        tests/test_functionality.py:107 d     1      0.000000  0.000001  0.000001
-        '''
-        self.assert_traces_almost_equal(r1, stats)
-        self.assertEqual(len(stats), 4)
-
-        stats = yappi.get_func_stats(
-            filter_callback=lambda x: yappi.func_matches(x, [time.sleep])
-        )
-        self.assertEqual(len(stats), 1)
-        r1 = '''
-        time.sleep                            2      0.206804  0.220000  0.103402
-        '''
-        self.assert_traces_almost_equal(r1, stats)
-
-    def test_print_formatting(self):
-
-        def a():
-            pass
-
-        def b():
-            a()
-
-        func_cols = {
-            1: ("name", 48),
-            0: ("ncall", 5),
-            2: ("tsub", 8),
-        }
-        thread_cols = {
-            1: ("name", 48),
-            0: ("ttot", 8),
-        }
-
-        yappi.start()
-        a()
-        b()
-        yappi.stop()
-        fs = yappi.get_func_stats()
-        cs = fs[1].children
-        ts = yappi.get_thread_stats()
-        #fs.print_all(out=sys.stderr, columns={1:("name", 70), })
-        #cs.print_all(out=sys.stderr, columns=func_cols)
-        #ts.print_all(out=sys.stderr, columns=thread_cols)
-        #cs.print_all(out=sys.stderr, columns={})
-
-        self.assertRaises(
-            yappi.YappiError, fs.print_all, columns={1: ("namee", 9)}
-        )
-        self.assertRaises(
-            yappi.YappiError, cs.print_all, columns={1: ("dd", 0)}
-        )
-        self.assertRaises(
-            yappi.YappiError, ts.print_all, columns={1: ("tidd", 0)}
-        )
-
-    def test_get_clock(self):
-        yappi.set_clock_type('cpu')
-        self.assertEqual('cpu', yappi.get_clock_type())
-        clock_info = yappi.get_clock_info()
-        self.assertTrue('api' in clock_info)
-        self.assertTrue('resolution' in clock_info)
-
-        yappi.set_clock_type('wall')
-        self.assertEqual('wall', yappi.get_clock_type())
-
-        t0 = yappi.get_clock_time()
-        time.sleep(0.1)
-        duration = yappi.get_clock_time() - t0
-        self.assertTrue(0.05 < duration < 0.3)
-
-    def test_profile_decorator(self):
-
-        def aggregate(func, stats):
-            fname = "tests/%s.profile" % (func.__name__)
-            try:
-                stats.add(fname)
-            except IOError:
-                pass
-            stats.save(fname)
-            raise Exception("messing around")
-
-        @yappi.profile(return_callback=aggregate)
-        def a(x, y):
-            if x + y == 25:
-                raise Exception("")
-            return x + y
-
-        def b():
-            pass
-
-        try:
-            os.remove(
-                "tests/a.profile"
-            )  # remove the one from prev test, if available
-        except:
-            pass
-
-        # global profile is on to mess things up
-        yappi.start()
-        b()
-
-        # assert functionality and call function at same time
-        try:
-            self.assertEqual(a(1, 2), 3)
-        except:
-            pass
-        try:
-            self.assertEqual(a(2, 5), 7)
-        except:
-            pass
-        try:
-            a(4, 21)
-        except:
-            pass
-        stats = yappi.get_func_stats().add("tests/a.profile")
-        fsa = utils.find_stat_by_name(stats, 'a')
-        self.assertEqual(fsa.ncall, 3)
-        self.assertEqual(len(stats), 1)  # b() should be cleared out.
-
-        @yappi.profile(return_callback=aggregate)
-        def count_down_rec(n):
-            if n == 0:
-                return
-            count_down_rec(n - 1)
-
-        try:
-            os.remove(
-                "tests/count_down_rec.profile"
-            )  # remove the one from prev test, if available
-        except:
-            pass
-
-        try:
-            count_down_rec(4)
-        except:
-            pass
-        try:
-            count_down_rec(3)
-        except:
-            pass
-
-        stats = yappi.YFuncStats("tests/count_down_rec.profile")
-        fsrec = utils.find_stat_by_name(stats, 'count_down_rec')
-        self.assertEqual(fsrec.ncall, 9)
-        self.assertEqual(fsrec.nactualcall, 2)
-
-    def test_strip_dirs(self):
-
-        def a():
-            pass
-
-        stats = utils.run_and_get_func_stats(a, )
-        stats.strip_dirs()
-        fsa = utils.find_stat_by_name(stats, "a")
-        self.assertEqual(fsa.module, os.path.basename(fsa.module))
-
-    @unittest.skipIf(os.name == "nt", "do not run on Windows")
-    def test_run_as_script(self):
-        import re
-        p = subprocess.Popen(
-            ['yappi', os.path.join('./tests', 'run_as_script.py')],
-            stdout=subprocess.PIPE
-        )
-        out, err = p.communicate()
-        self.assertEqual(p.returncode, 0)
-        func_stats, thread_stats = re.split(
-            b'name\\s+id\\s+tid\\s+ttot\\s+scnt\\s*\n', out
-        )
-        self.assertTrue(b'FancyThread' in thread_stats)
-
-    def test_yappi_overhead(self):
-        LOOP_COUNT = 100000
-
-        def a():
-            pass
-
-        def b():
-            for i in range(LOOP_COUNT):
-                a()
-
-        t0 = time.time()
-        yappi.start()
-        b()
-        yappi.stop()
-        time_with_yappi = time.time() - t0
-        t0 = time.time()
-        b()
-        time_without_yappi = time.time() - t0
-        if time_without_yappi == 0:
-            time_without_yappi = 0.000001
-
-        # in latest v0.82, I calculated this as close to "7.0" in my machine.
-        # however, %83 of this overhead is coming from tickcount(). The other %17
-        # seems to have been evenly distributed to the internal bookkeeping
-        # structures/algorithms which seems acceptable. Note that our test only
-        # tests one function being profiled at-a-time in a short interval.
-        # profiling high number of functions in a small time
-        # is a different beast, (which is pretty unlikely in most applications)
-        # So as a conclusion: I cannot see any optimization window for Yappi that
-        # is worth implementing as we will only optimize %17 of the time.
-        sys.stderr.write("\r\nYappi puts %0.1f times overhead to the profiled application in average.\r\n" % \
-            (time_with_yappi / time_without_yappi))
-
-    def test_clear_stats_while_running(self):
-
-        def a():
-            pass
-
-        yappi.start()
-        a()
-        yappi.clear_stats()
-        a()
-        stats = yappi.get_func_stats()
-        fsa = utils.find_stat_by_name(stats, 'a')
-        self.assertEqual(fsa.ncall, 1)
-
-    def test_generator(self):
-
-        def _gen(n):
-            while (n > 0):
-                yield n
-                n -= 1
-
-        yappi.start()
-        for x in _gen(5):
-            pass
-        self.assertTrue(
-            yappi.convert2pstats(yappi.get_func_stats()) is not None
-        )
-
-    def test_slice_child_stats_and_strip_dirs(self):
-
-        def b():
-            for i in range(10000000):
-                pass
-
-        def a():
-            b()
-
-        yappi.start(builtins=True)
-        a()
-        stats = yappi.get_func_stats()
-        fsa = utils.find_stat_by_name(stats, 'a')
-        fsb = utils.find_stat_by_name(stats, 'b')
-        self.assertTrue(fsa.children[0:1] is not None)
-        prev_afullname = fsa.full_name
-        prev_bchildfullname = fsa.children[fsb].full_name
-        stats.strip_dirs()
-        self.assertTrue(len(prev_afullname) > len(fsa.full_name))
-        self.assertTrue(
-            len(prev_bchildfullname) > len(fsa.children[fsb].full_name)
-        )
-
-    def test_children_stat_functions(self):
-        _timings = {"a_1": 5, "b_1": 3, "c_1": 1}
-        _yappi._set_test_timings(_timings)
-
-        def b():
-            pass
-
-        def c():
-            pass
-
-        def a():
-            b()
-            c()
-
-        yappi.start()
-        a()
-        b()  # non-child call
-        c()  # non-child call
-        stats = yappi.get_func_stats()
-        fsa = utils.find_stat_by_name(stats, 'a')
-        childs_of_a = fsa.children.get().sort("tavg", "desc")
-        prev_item = None
-        for item in childs_of_a:
-            if prev_item:
-                self.assertTrue(prev_item.tavg > item.tavg)
-            prev_item = item
-        childs_of_a.sort("name", "desc")
-        prev_item = None
-        for item in childs_of_a:
-            if prev_item:
-                self.assertTrue(prev_item.name > item.name)
-            prev_item = item
-        childs_of_a.clear()
-        self.assertTrue(childs_of_a.empty())
-
-    def test_no_stats_different_clock_type_load(self):
-
-        def a():
-            pass
-
-        yappi.start()
-        a()
-        yappi.stop()
-        yappi.get_func_stats().save("tests/ystats1.ys")
-        yappi.clear_stats()
-        yappi.set_clock_type("WALL")
-        yappi.start()
-        yappi.stop()
-        stats = yappi.get_func_stats().add("tests/ystats1.ys")
-        fsa = utils.find_stat_by_name(stats, 'a')
-        self.assertTrue(fsa is not None)
-
-    def test_subsequent_profile(self):
-        _timings = {"a_1": 1, "b_1": 1}
-        _yappi._set_test_timings(_timings)
-
-        def a():
-            pass
-
-        def b():
-            pass
-
-        yappi.start()
-        a()
-        yappi.stop()
-        yappi.start()
-        b()
-        yappi.stop()
-        stats = yappi.get_func_stats()
-        fsa = utils.find_stat_by_name(stats, 'a')
-        fsb = utils.find_stat_by_name(stats, 'b')
-        self.assertTrue(fsa is not None)
-        self.assertTrue(fsb is not None)
-        self.assertEqual(fsa.ttot, 1)
-        self.assertEqual(fsb.ttot, 1)
-
-    def test_lambda(self):
-        f = lambda: time.sleep(0.3)
-        yappi.set_clock_type("wall")
-        yappi.start()
-        f()
-        stats = yappi.get_func_stats()
-        fsa = utils.find_stat_by_name(stats, '<lambda>')
-        self.assertTrue(fsa.ttot > 0.1)
-
-    def test_module_stress(self):
-        self.assertEqual(yappi.is_running(), False)
-
-        yappi.start()
-        yappi.clear_stats()
-        self.assertRaises(_yappi.error, yappi.set_clock_type, "wall")
-
-        yappi.stop()
-        yappi.clear_stats()
-        yappi.set_clock_type("cpu")
-        self.assertRaises(yappi.YappiError, yappi.set_clock_type, "dummy")
-        self.assertEqual(yappi.is_running(), False)
-        yappi.clear_stats()
-        yappi.clear_stats()
-
-    def test_stat_sorting(self):
-        _timings = {"a_1": 13, "b_1": 10, "a_2": 6, "b_2": 1}
-        _yappi._set_test_timings(_timings)
-
-        self._ncall = 1
-
-        def a():
-            b()
-
-        def b():
-            if self._ncall == 2:
-                return
-            self._ncall += 1
-            a()
-
-        stats = utils.run_and_get_func_stats(a)
-        stats = stats.sort("totaltime", "desc")
-        prev_stat = None
-        for stat in stats:
-            if prev_stat:
-                self.assertTrue(prev_stat.ttot >= stat.ttot)
-            prev_stat = stat
-        stats = stats.sort("totaltime", "asc")
-        prev_stat = None
-        for stat in stats:
-            if prev_stat:
-                self.assertTrue(prev_stat.ttot <= stat.ttot)
-            prev_stat = stat
-        stats = stats.sort("avgtime", "asc")
-        prev_stat = None
-        for stat in stats:
-            if prev_stat:
-                self.assertTrue(prev_stat.tavg <= stat.tavg)
-            prev_stat = stat
-        stats = stats.sort("name", "asc")
-        prev_stat = None
-        for stat in stats:
-            if prev_stat:
-                self.assertTrue(prev_stat.name <= stat.name)
-            prev_stat = stat
-        stats = stats.sort("subtime", "asc")
-        prev_stat = None
-        for stat in stats:
-            if prev_stat:
-                self.assertTrue(prev_stat.tsub <= stat.tsub)
-            prev_stat = stat
-
-        self.assertRaises(
-            yappi.YappiError, stats.sort, "invalid_func_sorttype_arg"
-        )
-        self.assertRaises(
-            yappi.YappiError, stats.sort, "totaltime",
-            "invalid_func_sortorder_arg"
-        )
-
-    def test_start_flags(self):
-        self.assertEqual(_yappi._get_start_flags(), None)
-        yappi.start()
-
-        def a():
-            pass
-
-        a()
-        self.assertEqual(_yappi._get_start_flags()["profile_builtins"], 0)
-        self.assertEqual(_yappi._get_start_flags()["profile_multicontext"], 1)
-        self.assertEqual(len(yappi.get_thread_stats()), 1)
-
-    def test_builtin_profiling(self):
-
-        def a():
-            time.sleep(0.4)  # is a builtin function
-
-        yappi.set_clock_type('wall')
-
-        yappi.start(builtins=True)
-        a()
-        stats = yappi.get_func_stats()
-        fsa = utils.find_stat_by_name(stats, 'sleep')
-        self.assertTrue(fsa is not None)
-        self.assertTrue(fsa.ttot > 0.3)
-        yappi.stop()
-        yappi.clear_stats()
-
-        def a():
-            pass
-
-        yappi.start()
-        t = threading.Thread(target=a)
-        t.start()
-        t.join()
-        stats = yappi.get_func_stats()
-
-    def test_singlethread_profiling(self):
-        yappi.set_clock_type('wall')
-
-        def a():
-            time.sleep(0.2)
-
-        class Worker1(threading.Thread):
-
-            def a(self):
-                time.sleep(0.3)
-
-            def run(self):
-                self.a()
-
-        yappi.start(profile_threads=False)
-
-        c = Worker1()
-        c.start()
-        c.join()
-        a()
-        stats = yappi.get_func_stats()
-        fsa1 = utils.find_stat_by_name(stats, 'Worker1.a')
-        fsa2 = utils.find_stat_by_name(stats, 'a')
-        self.assertTrue(fsa1 is None)
-        self.assertTrue(fsa2 is not None)
-        self.assertTrue(fsa2.ttot > 0.1)
-
-    def test_run(self):
-
-        def profiled():
-            pass
-
-        yappi.clear_stats()
-        try:
-            with yappi.run():
-                profiled()
-            stats = yappi.get_func_stats()
-        finally:
-            yappi.clear_stats()
-
-        self.assertIsNotNone(utils.find_stat_by_name(stats, 'profiled'))
-
-    def test_run_recursive(self):
-
-        def profiled():
-            pass
-
-        def not_profiled():
-            pass
-
-        yappi.clear_stats()
-        try:
-            with yappi.run():
-                with yappi.run():
-                    profiled()
-                # Profiling stopped here
-                not_profiled()
-            stats = yappi.get_func_stats()
-        finally:
-            yappi.clear_stats()
-
-        self.assertIsNotNone(utils.find_stat_by_name(stats, 'profiled'))
-        self.assertIsNone(utils.find_stat_by_name(stats, 'not_profiled'))
-
-
-class StatSaveScenarios(utils.YappiUnitTestCase):
-
-    def test_pstats_conversion(self):
-
-        def pstat_id(fs):
-            return (fs.module, fs.lineno, fs.name)
-
-        def a():
-            d()
-
-        def b():
-            d()
-
-        def c():
-            pass
-
-        def d():
-            pass
-
-        _timings = {"a_1": 12, "b_1": 7, "c_1": 5, "d_1": 2}
-        _yappi._set_test_timings(_timings)
-        stats = utils.run_and_get_func_stats(a, )
-        stats.strip_dirs()
-        stats.save("tests/a1.pstats", type="pstat")
-        fsa_pid = pstat_id(utils.find_stat_by_name(stats, "a"))
-        fsd_pid = pstat_id(utils.find_stat_by_name(stats, "d"))
-        yappi.clear_stats()
-        _yappi._set_test_timings(_timings)
-        stats = utils.run_and_get_func_stats(a, )
-        stats.strip_dirs()
-        stats.save("tests/a2.pstats", type="pstat")
-        yappi.clear_stats()
-        _yappi._set_test_timings(_timings)
-        stats = utils.run_and_get_func_stats(b, )
-        stats.strip_dirs()
-        stats.save("tests/b1.pstats", type="pstat")
-        fsb_pid = pstat_id(utils.find_stat_by_name(stats, "b"))
-        yappi.clear_stats()
-        _yappi._set_test_timings(_timings)
-        stats = utils.run_and_get_func_stats(c, )
-        stats.strip_dirs()
-        stats.save("tests/c1.pstats", type="pstat")
-        fsc_pid = pstat_id(utils.find_stat_by_name(stats, "c"))
-
-        # merge saved stats and check pstats values are correct
-        import pstats
-        p = pstats.Stats(
-            'tests/a1.pstats', 'tests/a2.pstats', 'tests/b1.pstats',
-            'tests/c1.pstats'
-        )
-        p.strip_dirs()
-        # ct = ttot, tt = tsub
-        (cc, nc, tt, ct, callers) = p.stats[fsa_pid]
-        self.assertEqual(cc, nc, 2)
-        self.assertEqual(tt, 20)
-        self.assertEqual(ct, 24)
-        (cc, nc, tt, ct, callers) = p.stats[fsd_pid]
-        self.assertEqual(cc, nc, 3)
-        self.assertEqual(tt, 6)
-        self.assertEqual(ct, 6)
-        self.assertEqual(len(callers), 2)
-        (cc, nc, tt, ct) = callers[fsa_pid]
-        self.assertEqual(cc, nc, 2)
-        self.assertEqual(tt, 4)
-        self.assertEqual(ct, 4)
-        (cc, nc, tt, ct) = callers[fsb_pid]
-        self.assertEqual(cc, nc, 1)
-        self.assertEqual(tt, 2)
-        self.assertEqual(ct, 2)
-
-    def test_merge_stats(self):
-        _timings = {
-            "a_1": 15,
-            "b_1": 14,
-            "c_1": 12,
-            "d_1": 10,
-            "e_1": 9,
-            "f_1": 7,
-            "g_1": 6,
-            "h_1": 5,
-            "i_1": 1
-        }
-        _yappi._set_test_timings(_timings)
-
-        def a():
-            b()
-
-        def b():
-            c()
-
-        def c():
-            d()
-
-        def d():
-            e()
-
-        def e():
-            f()
-
-        def f():
-            g()
-
-        def g():
-            h()
-
-        def h():
-            i()
-
-        def i():
-            pass
-
-        yappi.start()
-        a()
-        a()
-        yappi.stop()
-        stats = yappi.get_func_stats()
-        self.assertRaises(
-            NotImplementedError, stats.save, "", "INVALID_SAVE_TYPE"
-        )
-        stats.save("tests/ystats2.ys")
-        yappi.clear_stats()
-        _yappi._set_test_timings(_timings)
-        yappi.start()
-        a()
-        stats = yappi.get_func_stats().add("tests/ystats2.ys")
-        fsa = utils.find_stat_by_name(stats, "a")
-        fsb = utils.find_stat_by_name(stats, "b")
-        fsc = utils.find_stat_by_name(stats, "c")
-        fsd = utils.find_stat_by_name(stats, "d")
-        fse = utils.find_stat_by_name(stats, "e")
-        fsf = utils.find_stat_by_name(stats, "f")
-        fsg = utils.find_stat_by_name(stats, "g")
-        fsh = utils.find_stat_by_name(stats, "h")
-        fsi = utils.find_stat_by_name(stats, "i")
-        self.assertEqual(fsa.ttot, 45)
-        self.assertEqual(fsa.ncall, 3)
-        self.assertEqual(fsa.nactualcall, 3)
-        self.assertEqual(fsa.tsub, 3)
-        self.assertEqual(fsa.children[fsb].ttot, fsb.ttot)
-        self.assertEqual(fsa.children[fsb].tsub, fsb.tsub)
-        self.assertEqual(fsb.children[fsc].ttot, fsc.ttot)
-        self.assertEqual(fsb.children[fsc].tsub, fsc.tsub)
-        self.assertEqual(fsc.tsub, 6)
-        self.assertEqual(fsc.children[fsd].ttot, fsd.ttot)
-        self.assertEqual(fsc.children[fsd].tsub, fsd.tsub)
-        self.assertEqual(fsd.children[fse].ttot, fse.ttot)
-        self.assertEqual(fsd.children[fse].tsub, fse.tsub)
-        self.assertEqual(fse.children[fsf].ttot, fsf.ttot)
-        self.assertEqual(fse.children[fsf].tsub, fsf.tsub)
-        self.assertEqual(fsf.children[fsg].ttot, fsg.ttot)
-        self.assertEqual(fsf.children[fsg].tsub, fsg.tsub)
-        self.assertEqual(fsg.ttot, 18)
-        self.assertEqual(fsg.tsub, 3)
-        self.assertEqual(fsg.children[fsh].ttot, fsh.ttot)
-        self.assertEqual(fsg.children[fsh].tsub, fsh.tsub)
-        self.assertEqual(fsh.ttot, 15)
-        self.assertEqual(fsh.tsub, 12)
-        self.assertEqual(fsh.tavg, 5)
-        self.assertEqual(fsh.children[fsi].ttot, fsi.ttot)
-        self.assertEqual(fsh.children[fsi].tsub, fsi.tsub)
-        #stats.debug_print()
-
-    def test_merge_multithreaded_stats(self):
-        import _yappi
-        timings = {"a_1": 2, "b_1": 1}
-        _yappi._set_test_timings(timings)
-
-        def a():
-            pass
-
-        def b():
-            pass
-
-        yappi.start()
-        t = threading.Thread(target=a)
-        t.start()
-        t.join()
-        t = threading.Thread(target=b)
-        t.start()
-        t.join()
-        yappi.get_func_stats().save("tests/ystats1.ys")
-        yappi.clear_stats()
-        _yappi._set_test_timings(timings)
-        self.assertEqual(len(yappi.get_func_stats()), 0)
-        self.assertEqual(len(yappi.get_thread_stats()), 1)
-        t = threading.Thread(target=a)
-        t.start()
-        t.join()
-
-        self.assertEqual(_yappi._get_start_flags()["profile_builtins"], 0)
-        self.assertEqual(_yappi._get_start_flags()["profile_multicontext"], 1)
-        yappi.get_func_stats().save("tests/ystats2.ys")
-
-        stats = yappi.YFuncStats([
-            "tests/ystats1.ys",
-            "tests/ystats2.ys",
-        ])
-        fsa = utils.find_stat_by_name(stats, "a")
-        fsb = utils.find_stat_by_name(stats, "b")
-        self.assertEqual(fsa.ncall, 2)
-        self.assertEqual(fsb.ncall, 1)
-        self.assertEqual(fsa.tsub, fsa.ttot, 4)
-        self.assertEqual(fsb.tsub, fsb.ttot, 1)
-
-    def test_merge_load_different_clock_types(self):
-        yappi.start(builtins=True)
-
-        def a():
-            b()
-
-        def b():
-            c()
-
-        def c():
-            pass
-
-        t = threading.Thread(target=a)
-        t.start()
-        t.join()
-        yappi.get_func_stats().sort("name", "asc").save("tests/ystats1.ys")
-        yappi.stop()
-        yappi.clear_stats()
-        yappi.start(builtins=False)
-        t = threading.Thread(target=a)
-        t.start()
-        t.join()
-        yappi.get_func_stats().save("tests/ystats2.ys")
-        yappi.stop()
-        self.assertRaises(_yappi.error, yappi.set_clock_type, "wall")
-        yappi.clear_stats()
-        yappi.set_clock_type("wall")
-        yappi.start()
-        t = threading.Thread(target=a)
-        t.start()
-        t.join()
-        yappi.get_func_stats().save("tests/ystats3.ys")
-        self.assertRaises(
-            yappi.YappiError,
-            yappi.YFuncStats().add("tests/ystats1.ys").add, "tests/ystats3.ys"
-        )
-        stats = yappi.YFuncStats(["tests/ystats1.ys",
-                                  "tests/ystats2.ys"]).sort("name")
-        fsa = utils.find_stat_by_name(stats, "a")
-        fsb = utils.find_stat_by_name(stats, "b")
-        fsc = utils.find_stat_by_name(stats, "c")
-        self.assertEqual(fsa.ncall, 2)
-        self.assertEqual(fsa.ncall, fsb.ncall, fsc.ncall)
-
-    def test_merge_aabab_aabbc(self):
-        _timings = {
-            "a_1": 15,
-            "a_2": 14,
-            "b_1": 12,
-            "a_3": 10,
-            "b_2": 9,
-            "c_1": 4
-        }
-        _yappi._set_test_timings(_timings)
-
-        def a():
-            if self._ncall == 1:
-                self._ncall += 1
-                a()
-            elif self._ncall == 5:
-                self._ncall += 1
-                a()
-            else:
-                b()
-
-        def b():
-            if self._ncall == 2:
-                self._ncall += 1
-                a()
-            elif self._ncall == 6:
-                self._ncall += 1
-                b()
-            elif self._ncall == 7:
-                c()
-            else:
-                return
-
-        def c():
-            pass
-
-        self._ncall = 1
-        stats = utils.run_and_get_func_stats(a, )
-        stats.save("tests/ystats1.ys")
-        yappi.clear_stats()
-        _yappi._set_test_timings(_timings)
-        #stats.print_all()
-
-        self._ncall = 5
-        stats = utils.run_and_get_func_stats(a, )
-        stats.save("tests/ystats2.ys")
-
-        #stats.print_all()
-
-        def a():  # same name but another function(code object)
-            pass
-
-        yappi.start()
-        a()
-        stats = yappi.get_func_stats().add(
-            ["tests/ystats1.ys", "tests/ystats2.ys"]
-        )
-        #stats.print_all()
-        self.assertEqual(len(stats), 4)
-
-        fsa = None
-        for stat in stats:
-            if stat.name == "a" and stat.ttot == 45:
-                fsa = stat
-                break
-        self.assertTrue(fsa is not None)
-
-        self.assertEqual(fsa.ncall, 7)
-        self.assertEqual(fsa.nactualcall, 3)
-        self.assertEqual(fsa.ttot, 45)
-        self.assertEqual(fsa.tsub, 10)
-        fsb = utils.find_stat_by_name(stats, "b")
-        fsc = utils.find_stat_by_name(stats, "c")
-        self.assertEqual(fsb.ncall, 6)
-        self.assertEqual(fsb.nactualcall, 3)
-        self.assertEqual(fsb.ttot, 36)
-        self.assertEqual(fsb.tsub, 27)
-        self.assertEqual(fsb.tavg, 6)
-        self.assertEqual(fsc.ttot, 8)
-        self.assertEqual(fsc.tsub, 8)
-        self.assertEqual(fsc.tavg, 4)
-        self.assertEqual(fsc.nactualcall, fsc.ncall, 2)
-
-
-class MultithreadedScenarios(utils.YappiUnitTestCase):
-
-    def test_issue_32(self):
-        '''
-        Start yappi from different thread and we get Internal Error(15) as 
-        the current_ctx_id() called while enumerating the threads in start() 
-        and as it does not swap to the enumerated ThreadState* the THreadState_GetDict()
-        returns wrong object and thus sets an invalid id for the _ctx structure.
-
-        When this issue happens multiple Threads have same tid as the internal ts_ptr
-        will be same for different contexts. So, let's see if that happens
-        '''
-
-        def foo():
-            time.sleep(0.2)
-
-        def bar():
-            time.sleep(0.1)
-
-        def thread_func():
-            yappi.set_clock_type("wall")
-            yappi.start()
-
-            bar()
-
-        t = threading.Thread(target=thread_func)
-        t.start()
-        t.join()
-
-        foo()
-
-        yappi.stop()
-
-        thread_ids = set()
-        for tstat in yappi.get_thread_stats():
-            self.assertTrue(tstat.tid not in thread_ids)
-            thread_ids.add(tstat.tid)
-
-    def test_subsequent_profile(self):
-        WORKER_COUNT = 5
-
-        def a():
-            pass
-
-        def b():
-            pass
-
-        def c():
-            pass
-
-        _timings = {
-            "a_1": 3,
-            "b_1": 2,
-            "c_1": 1,
-        }
-
-        yappi.start()
-
-        def g():
-            pass
-
-        g()
-        yappi.stop()
-        yappi.clear_stats()
-        _yappi._set_test_timings(_timings)
-        yappi.start()
-
-        _dummy = []
-        for i in range(WORKER_COUNT):
-            t = threading.Thread(target=a)
-            t.start()
-            t.join()
-        for i in range(WORKER_COUNT):
-            t = threading.Thread(target=b)
-            t.start()
-            _dummy.append(t)
-            t.join()
-        for i in range(WORKER_COUNT):
-            t = threading.Thread(target=a)
-            t.start()
-            t.join()
-        for i in range(WORKER_COUNT):
-            t = threading.Thread(target=c)
-            t.start()
-            t.join()
-        yappi.stop()
-        yappi.start()
-
-        def f():
-            pass
-
-        f()
-        stats = yappi.get_func_stats()
-        fsa = utils.find_stat_by_name(stats, 'a')
-        fsb = utils.find_stat_by_name(stats, 'b')
-        fsc = utils.find_stat_by_name(stats, 'c')
-        self.assertEqual(fsa.ncall, 10)
-        self.assertEqual(fsb.ncall, 5)
-        self.assertEqual(fsc.ncall, 5)
-        self.assertEqual(fsa.ttot, fsa.tsub, 30)
-        self.assertEqual(fsb.ttot, fsb.tsub, 10)
-        self.assertEqual(fsc.ttot, fsc.tsub, 5)
-
-        # MACOSx optimizes by only creating one worker thread
-        self.assertTrue(len(yappi.get_thread_stats()) >= 2)
-
-    def test_basic(self):
-        yappi.set_clock_type('wall')
-
-        def dummy():
-            pass
-
-        def a():
-            time.sleep(0.2)
-
-        class Worker1(threading.Thread):
-
-            def a(self):
-                time.sleep(0.3)
-
-            def run(self):
-                self.a()
-
-        yappi.start(builtins=False, profile_threads=True)
-
-        c = Worker1()
-        c.start()
-        c.join()
-        a()
-        stats = yappi.get_func_stats()
-        fsa1 = utils.find_stat_by_name(stats, 'Worker1.a')
-        fsa2 = utils.find_stat_by_name(stats, 'a')
-        self.assertTrue(fsa1 is not None)
-        self.assertTrue(fsa2 is not None)
-        self.assertTrue(fsa1.ttot > 0.2)
-        self.assertTrue(fsa2.ttot > 0.1)
-        tstats = yappi.get_thread_stats()
-        self.assertEqual(len(tstats), 2)
-        tsa = utils.find_stat_by_name(tstats, 'Worker1')
-        tsm = utils.find_stat_by_name(tstats, '_MainThread')
-        dummy()  # call dummy to force ctx name to be retrieved again.
-        self.assertTrue(tsa is not None)
-        # TODO: I put dummy() to fix below, remove the comments after a while.
-        self.assertTrue( # FIX: I see this fails sometimes?
-            tsm is not None,
-            'Could not find "_MainThread". Found: %s' % (', '.join(utils.get_stat_names(tstats))))
-
-    def test_ctx_stats(self):
-        from threading import Thread
-        DUMMY_WORKER_COUNT = 5
-        yappi.start()
-
-        class DummyThread(Thread):
-            pass
-
-        def dummy():
-            pass
-
-        def dummy_worker():
-            pass
-
-        for i in range(DUMMY_WORKER_COUNT):
-            t = DummyThread(target=dummy_worker)
-            t.start()
-            t.join()
-        yappi.stop()
-        stats = yappi.get_thread_stats()
-        tsa = utils.find_stat_by_name(stats, "DummyThread")
-        self.assertTrue(tsa is not None)
-        yappi.clear_stats()
-        time.sleep(1.0)
-        _timings = {
-            "a_1": 6,
-            "b_1": 5,
-            "c_1": 3,
-            "d_1": 1,
-            "a_2": 4,
-            "b_2": 3,
-            "c_2": 2,
-            "d_2": 1
-        }
-        _yappi._set_test_timings(_timings)
-
-        class Thread1(Thread):
-            pass
-
-        class Thread2(Thread):
-            pass
-
-        def a():
-            b()
-
-        def b():
-            c()
-
-        def c():
-            d()
-
-        def d():
-            time.sleep(0.6)
-
-        yappi.set_clock_type("wall")
-        yappi.start()
-        t1 = Thread1(target=a)
-        t1.start()
-        t2 = Thread2(target=a)
-        t2.start()
-        t1.join()
-        t2.join()
-        stats = yappi.get_thread_stats()
-
-        # the fist clear_stats clears the context table?
-        tsa = utils.find_stat_by_name(stats, "DummyThread")
-        self.assertTrue(tsa is None)
-
-        tst1 = utils.find_stat_by_name(stats, "Thread1")
-        tst2 = utils.find_stat_by_name(stats, "Thread2")
-        tsmain = utils.find_stat_by_name(stats, "_MainThread")
-        dummy()  # call dummy to force ctx name to be retrieved again.
-        self.assertTrue(len(stats) == 3)
-        self.assertTrue(tst1 is not None)
-        self.assertTrue(tst2 is not None)
-        # TODO: I put dummy() to fix below, remove the comments after a while.
-        self.assertTrue( # FIX: I see this fails sometimes
-            tsmain is not None,
-            'Could not find "_MainThread". Found: %s' % (', '.join(utils.get_stat_names(stats))))
-        self.assertTrue(1.0 > tst2.ttot >= 0.5)
-        self.assertTrue(1.0 > tst1.ttot >= 0.5)
-
-        # test sorting of the ctx stats
-        stats = stats.sort("totaltime", "desc")
-        prev_stat = None
-        for stat in stats:
-            if prev_stat:
-                self.assertTrue(prev_stat.ttot >= stat.ttot)
-            prev_stat = stat
-        stats = stats.sort("totaltime", "asc")
-        prev_stat = None
-        for stat in stats:
-            if prev_stat:
-                self.assertTrue(prev_stat.ttot <= stat.ttot)
-            prev_stat = stat
-        stats = stats.sort("schedcount", "desc")
-        prev_stat = None
-        for stat in stats:
-            if prev_stat:
-                self.assertTrue(prev_stat.sched_count >= stat.sched_count)
-            prev_stat = stat
-        stats = stats.sort("name", "desc")
-        prev_stat = None
-        for stat in stats:
-            if prev_stat:
-                self.assertTrue(prev_stat.name.lower() >= stat.name.lower())
-            prev_stat = stat
-        self.assertRaises(
-            yappi.YappiError, stats.sort, "invalid_thread_sorttype_arg"
-        )
-        self.assertRaises(
-            yappi.YappiError, stats.sort, "invalid_thread_sortorder_arg"
-        )
-
-    def test_ctx_stats_cpu(self):
-
-        def get_thread_name():
-            try:
-                return threading.current_thread().name
-            except AttributeError:
-                return "Anonymous"
-
-        def burn_cpu(sec):
-            t0 = yappi.get_clock_time()
-            elapsed = 0
-            while (elapsed < sec):
-                for _ in range(1000):
-                    pass
-                elapsed = yappi.get_clock_time() - t0
-
-        def test():
-
-            ts = []
-            for i in (0.01, 0.05, 0.1):
-                t = threading.Thread(target=burn_cpu, args=(i, ))
-                t.name = "burn_cpu-%s" % str(i)
-                t.start()
-                ts.append(t)
-            for t in ts:
-                t.join()
-
-        yappi.set_clock_type("cpu")
-        yappi.set_context_name_callback(get_thread_name)
-
-        yappi.start()
-
-        test()
-
-        yappi.stop()
-
-        tstats = yappi.get_thread_stats()
-        r1 = '''
-        burn_cpu-0.1      3      123145356058624  0.100105  8
-        burn_cpu-0.05     2      123145361313792  0.050149  8
-        burn_cpu-0.01     1      123145356058624  0.010127  2
-        MainThread        0      4321620864       0.001632  6
-        '''
-        self.assert_ctx_stats_almost_equal(r1, tstats)
-
-    def test_producer_consumer_with_queues(self):
-        # we currently just stress yappi, no functionality test is done here.
-        yappi.start()
-        if utils.is_py3x():
-            from queue import Queue
-        else:
-            from Queue import Queue
-        from threading import Thread
-        WORKER_THREAD_COUNT = 50
-        WORK_ITEM_COUNT = 2000
-
-        def worker():
-            while True:
-                item = q.get()
-                # do the work with item
-                q.task_done()
-
-        q = Queue()
-        for i in range(WORKER_THREAD_COUNT):
-            t = Thread(target=worker)
-            t.daemon = True
-            t.start()
-
-        for item in range(WORK_ITEM_COUNT):
-            q.put(item)
-        q.join()  # block until all tasks are done
-        #yappi.get_func_stats().sort("callcount").print_all()
-        yappi.stop()
-
-    def test_temporary_lock_waiting(self):
-        yappi.start()
-        _lock = threading.Lock()
-
-        def worker():
-            _lock.acquire()
-            try:
-                time.sleep(1.0)
-            finally:
-                _lock.release()
-
-        t1 = threading.Thread(target=worker)
-        t2 = threading.Thread(target=worker)
-        t1.start()
-        t2.start()
-        t1.join()
-        t2.join()
-        #yappi.get_func_stats().sort("callcount").print_all()
-        yappi.stop()
-
-    @unittest.skipIf(os.name != "posix", "requires Posix compliant OS")
-    def test_signals_with_blocking_calls(self):
-        import signal, os, time
-
-        # just to verify if signal is handled correctly and stats/yappi are not corrupted.
-        def handler(signum, frame):
-            raise Exception("Signal handler executed!")
-
-        yappi.start()
-        signal.signal(signal.SIGALRM, handler)
-        signal.alarm(1)
-        self.assertRaises(Exception, time.sleep, 2)
-        stats = yappi.get_func_stats()
-        fsh = utils.find_stat_by_name(stats, "handler")
-        self.assertTrue(fsh is not None)
-
-    @unittest.skipIf(not sys.version_info >= (3, 2), "requires Python 3.2")
-    def test_concurrent_futures(self):
-        yappi.start()
-        from concurrent.futures import ThreadPoolExecutor
-        with ThreadPoolExecutor(max_workers=5) as executor:
-            f = executor.submit(pow, 5, 2)
-            self.assertEqual(f.result(), 25)
-        time.sleep(1.0)
-        yappi.stop()
-
-    @unittest.skipIf(not sys.version_info >= (3, 2), "requires Python 3.2")
-    def test_barrier(self):
-        yappi.start()
-        b = threading.Barrier(2, timeout=1)
-
-        def worker():
-            try:
-                b.wait()
-            except threading.BrokenBarrierError:
-                pass
-            except Exception:
-                raise Exception("BrokenBarrierError not raised")
-
-        t1 = threading.Thread(target=worker)
-        t1.start()
-        #b.wait()
-        t1.join()
-        yappi.stop()
-
-
-class NonRecursiveFunctions(utils.YappiUnitTestCase):
-
-    def test_abcd(self):
-        _timings = {"a_1": 6, "b_1": 5, "c_1": 3, "d_1": 1}
-        _yappi._set_test_timings(_timings)
-
-        def a():
-            b()
-
-        def b():
-            c()
-
-        def c():
-            d()
-
-        def d():
-            pass
-
-        stats = utils.run_and_get_func_stats(a)
-        fsa = utils.find_stat_by_name(stats, 'a')
-        fsb = utils.find_stat_by_name(stats, 'b')
-        fsc = utils.find_stat_by_name(stats, 'c')
-        fsd = utils.find_stat_by_name(stats, 'd')
-        cfsab = fsa.children[fsb]
-        cfsbc = fsb.children[fsc]
-        cfscd = fsc.children[fsd]
-
-        self.assertEqual(fsa.ttot, 6)
-        self.assertEqual(fsa.tsub, 1)
-        self.assertEqual(fsb.ttot, 5)
-        self.assertEqual(fsb.tsub, 2)
-        self.assertEqual(fsc.ttot, 3)
-        self.assertEqual(fsc.tsub, 2)
-        self.assertEqual(fsd.ttot, 1)
-        self.assertEqual(fsd.tsub, 1)
-        self.assertEqual(cfsab.ttot, 5)
-        self.assertEqual(cfsab.tsub, 2)
-        self.assertEqual(cfsbc.ttot, 3)
-        self.assertEqual(cfsbc.tsub, 2)
-        self.assertEqual(cfscd.ttot, 1)
-        self.assertEqual(cfscd.tsub, 1)
-
-    def test_stop_in_middle(self):
-        _timings = {"a_1": 6, "b_1": 4}
-        _yappi._set_test_timings(_timings)
-
-        def a():
-            b()
-            yappi.stop()
-
-        def b():
-            time.sleep(0.2)
-
-        yappi.start()
-        a()
-        stats = yappi.get_func_stats()
-        fsa = utils.find_stat_by_name(stats, 'a')
-        fsb = utils.find_stat_by_name(stats, 'b')
-
-        self.assertEqual(fsa.ncall, 1)
-        self.assertEqual(fsa.nactualcall, 0)
-        self.assertEqual(fsa.ttot, 0)  # no call_leave called
-        self.assertEqual(fsa.tsub, 0)  # no call_leave called
-        self.assertEqual(fsb.ttot, 4)
-
-
-class RecursiveFunctions(utils.YappiUnitTestCase):
-
-    def test_fibonacci(self):
-
-        def fib(n):
-            if n > 1:
-                return fib(n - 1) + fib(n - 2)
-            else:
-                return n
-
-        stats = utils.run_and_get_func_stats(fib, 22)
-        fs = utils.find_stat_by_name(stats, 'fib')
-        self.assertEqual(fs.ncall, 57313)
-        self.assertEqual(fs.ttot, fs.tsub)
-
-    def test_abcadc(self):
-        _timings = {
-            "a_1": 20,
-            "b_1": 19,
-            "c_1": 17,
-            "a_2": 13,
-            "d_1": 12,
-            "c_2": 10,
-            "a_3": 5
-        }
-        _yappi._set_test_timings(_timings)
-
-        def a(n):
-            if n == 3:
-                return
-            if n == 1 + 1:
-                d(n)
-            else:
-                b(n)
-
-        def b(n):
-            c(n)
-
-        def c(n):
-            a(n + 1)
-
-        def d(n):
-            c(n)
-
-        stats = utils.run_and_get_func_stats(a, 1)
-        fsa = utils.find_stat_by_name(stats, 'a')
-        fsb = utils.find_stat_by_name(stats, 'b')
-        fsc = utils.find_stat_by_name(stats, 'c')
-        fsd = utils.find_stat_by_name(stats, 'd')
-        self.assertEqual(fsa.ncall, 3)
-        self.assertEqual(fsa.nactualcall, 1)
-        self.assertEqual(fsa.ttot, 20)
-        self.assertEqual(fsa.tsub, 7)
-        self.assertEqual(fsb.ttot, 19)
-        self.assertEqual(fsb.tsub, 2)
-        self.assertEqual(fsc.ttot, 17)
-        self.assertEqual(fsc.tsub, 9)
-        self.assertEqual(fsd.ttot, 12)
-        self.assertEqual(fsd.tsub, 2)
-        cfsca = fsc.children[fsa]
-        self.assertEqual(cfsca.nactualcall, 0)
-        self.assertEqual(cfsca.ncall, 2)
-        self.assertEqual(cfsca.ttot, 13)
-        self.assertEqual(cfsca.tsub, 6)
-
-    def test_aaaa(self):
-        _timings = {"d_1": 9, "d_2": 7, "d_3": 3, "d_4": 2}
-        _yappi._set_test_timings(_timings)
-
-        def d(n):
-            if n == 3:
-                return
-            d(n + 1)
-
-        stats = utils.run_and_get_func_stats(d, 0)
-        fsd = utils.find_stat_by_name(stats, 'd')
-        self.assertEqual(fsd.ncall, 4)
-        self.assertEqual(fsd.nactualcall, 1)
-        self.assertEqual(fsd.ttot, 9)
-        self.assertEqual(fsd.tsub, 9)
-        cfsdd = fsd.children[fsd]
-        self.assertEqual(cfsdd.ttot, 7)
-        self.assertEqual(cfsdd.tsub, 7)
-        self.assertEqual(cfsdd.ncall, 3)
-        self.assertEqual(cfsdd.nactualcall, 0)
-
-    def test_abcabc(self):
-        _timings = {
-            "a_1": 20,
-            "b_1": 19,
-            "c_1": 17,
-            "a_2": 13,
-            "b_2": 11,
-            "c_2": 9,
-            "a_3": 6
-        }
-        _yappi._set_test_timings(_timings)
-
-        def a(n):
-            if n == 3:
-                return
-            else:
-                b(n)
-
-        def b(n):
-            c(n)
-
-        def c(n):
-            a(n + 1)
-
-        stats = utils.run_and_get_func_stats(a, 1)
-        fsa = utils.find_stat_by_name(stats, 'a')
-        fsb = utils.find_stat_by_name(stats, 'b')
-        fsc = utils.find_stat_by_name(stats, 'c')
-        self.assertEqual(fsa.ncall, 3)
-        self.assertEqual(fsa.nactualcall, 1)
-        self.assertEqual(fsa.ttot, 20)
-        self.assertEqual(fsa.tsub, 9)
-        self.assertEqual(fsb.ttot, 19)
-        self.assertEqual(fsb.tsub, 4)
-        self.assertEqual(fsc.ttot, 17)
-        self.assertEqual(fsc.tsub, 7)
-        cfsab = fsa.children[fsb]
-        cfsbc = fsb.children[fsc]
-        cfsca = fsc.children[fsa]
-        self.assertEqual(cfsab.ttot, 19)
-        self.assertEqual(cfsab.tsub, 4)
-        self.assertEqual(cfsbc.ttot, 17)
-        self.assertEqual(cfsbc.tsub, 7)
-        self.assertEqual(cfsca.ttot, 13)
-        self.assertEqual(cfsca.tsub, 8)
-
-    def test_abcbca(self):
-        _timings = {"a_1": 10, "b_1": 9, "c_1": 7, "b_2": 4, "c_2": 2, "a_2": 1}
-        _yappi._set_test_timings(_timings)
-        self._ncall = 1
-
-        def a():
-            if self._ncall == 1:
-                b()
-            else:
-                return
-
-        def b():
-            c()
-
-        def c():
-            if self._ncall == 1:
-                self._ncall += 1
-                b()
-            else:
-                a()
-
-        stats = utils.run_and_get_func_stats(a)
-        fsa = utils.find_stat_by_name(stats, 'a')
-        fsb = utils.find_stat_by_name(stats, 'b')
-        fsc = utils.find_stat_by_name(stats, 'c')
-        cfsab = fsa.children[fsb]
-        cfsbc = fsb.children[fsc]
-        cfsca = fsc.children[fsa]
-        self.assertEqual(fsa.ttot, 10)
-        self.assertEqual(fsa.tsub, 2)
-        self.assertEqual(fsb.ttot, 9)
-        self.assertEqual(fsb.tsub, 4)
-        self.assertEqual(fsc.ttot, 7)
-        self.assertEqual(fsc.tsub, 4)
-        self.assertEqual(cfsab.ttot, 9)
-        self.assertEqual(cfsab.tsub, 2)
-        self.assertEqual(cfsbc.ttot, 7)
-        self.assertEqual(cfsbc.tsub, 4)
-        self.assertEqual(cfsca.ttot, 1)
-        self.assertEqual(cfsca.tsub, 1)
-        self.assertEqual(cfsca.ncall, 1)
-        self.assertEqual(cfsca.nactualcall, 0)
-
-    def test_aabccb(self):
-        _timings = {
-            "a_1": 13,
-            "a_2": 11,
-            "b_1": 9,
-            "c_1": 5,
-            "c_2": 3,
-            "b_2": 1
-        }
-        _yappi._set_test_timings(_timings)
-        self._ncall = 1
-
-        def a():
-            if self._ncall == 1:
-                self._ncall += 1
-                a()
-            else:
-                b()
-
-        def b():
-            if self._ncall == 3:
-                return
-            else:
-                c()
-
-        def c():
-            if self._ncall == 2:
-                self._ncall += 1
-                c()
-            else:
-                b()
-
-        stats = utils.run_and_get_func_stats(a)
-        fsa = utils.find_stat_by_name(stats, 'a')
-        fsb = utils.find_stat_by_name(stats, 'b')
-        fsc = utils.find_stat_by_name(stats, 'c')
-        cfsaa = fsa.children[fsa.index]
-        cfsab = fsa.children[fsb]
-        cfsbc = fsb.children[fsc.full_name]
-        cfscc = fsc.children[fsc]
-        cfscb = fsc.children[fsb]
-        self.assertEqual(fsb.ttot, 9)
-        self.assertEqual(fsb.tsub, 5)
-        self.assertEqual(cfsbc.ttot, 5)
-        self.assertEqual(cfsbc.tsub, 2)
-        self.assertEqual(fsa.ttot, 13)
-        self.assertEqual(fsa.tsub, 4)
-        self.assertEqual(cfsab.ttot, 9)
-        self.assertEqual(cfsab.tsub, 4)
-        self.assertEqual(cfsaa.ttot, 11)
-        self.assertEqual(cfsaa.tsub, 2)
-        self.assertEqual(fsc.ttot, 5)
-        self.assertEqual(fsc.tsub, 4)
-
-    def test_abaa(self):
-        _timings = {"a_1": 13, "b_1": 10, "a_2": 9, "a_3": 5}
-        _yappi._set_test_timings(_timings)
-
-        self._ncall = 1
-
-        def a():
-            if self._ncall == 1:
-                b()
-            elif self._ncall == 2:
-                self._ncall += 1
-                a()
-            else:
-                return
-
-        def b():
-            self._ncall += 1
-            a()
-
-        stats = utils.run_and_get_func_stats(a)
-        fsa = utils.find_stat_by_name(stats, 'a')
-        fsb = utils.find_stat_by_name(stats, 'b')
-        cfsaa = fsa.children[fsa]
-        cfsba = fsb.children[fsa]
-        self.assertEqual(fsb.ttot, 10)
-        self.assertEqual(fsb.tsub, 1)
-        self.assertEqual(fsa.ttot, 13)
-        self.assertEqual(fsa.tsub, 12)
-        self.assertEqual(cfsaa.ttot, 5)
-        self.assertEqual(cfsaa.tsub, 5)
-        self.assertEqual(cfsba.ttot, 9)
-        self.assertEqual(cfsba.tsub, 4)
-
-    def test_aabb(self):
-        _timings = {"a_1": 13, "a_2": 10, "b_1": 9, "b_2": 5}
-        _yappi._set_test_timings(_timings)
-
-        self._ncall = 1
-
-        def a():
-            if self._ncall == 1:
-                self._ncall += 1
-                a()
-            elif self._ncall == 2:
-                b()
-            else:
-                return
-
-        def b():
-            if self._ncall == 2:
-                self._ncall += 1
-                b()
-            else:
-                return
-
-        stats = utils.run_and_get_func_stats(a)
-        fsa = utils.find_stat_by_name(stats, 'a')
-        fsb = utils.find_stat_by_name(stats, 'b')
-        cfsaa = fsa.children[fsa]
-        cfsab = fsa.children[fsb]
-        cfsbb = fsb.children[fsb]
-        self.assertEqual(fsa.ttot, 13)
-        self.assertEqual(fsa.tsub, 4)
-        self.assertEqual(fsb.ttot, 9)
-        self.assertEqual(fsb.tsub, 9)
-        self.assertEqual(cfsaa.ttot, 10)
-        self.assertEqual(cfsaa.tsub, 1)
-        self.assertEqual(cfsab.ttot, 9)
-        self.assertEqual(cfsab.tsub, 4)
-        self.assertEqual(cfsbb.ttot, 5)
-        self.assertEqual(cfsbb.tsub, 5)
-
-    def test_abbb(self):
-        _timings = {"a_1": 13, "b_1": 10, "b_2": 6, "b_3": 1}
-        _yappi._set_test_timings(_timings)
-
-        self._ncall = 1
-
-        def a():
-            if self._ncall == 1:
-                b()
-
-        def b():
-            if self._ncall == 3:
-                return
-            self._ncall += 1
-            b()
-
-        stats = utils.run_and_get_func_stats(a)
-        fsa = utils.find_stat_by_name(stats, 'a')
-        fsb = utils.find_stat_by_name(stats, 'b')
-        cfsab = fsa.children[fsb]
-        cfsbb = fsb.children[fsb]
-        self.assertEqual(fsa.ttot, 13)
-        self.assertEqual(fsa.tsub, 3)
-        self.assertEqual(fsb.ttot, 10)
-        self.assertEqual(fsb.tsub, 10)
-        self.assertEqual(fsb.ncall, 3)
-        self.assertEqual(fsb.nactualcall, 1)
-        self.assertEqual(cfsab.ttot, 10)
-        self.assertEqual(cfsab.tsub, 4)
-        self.assertEqual(cfsbb.ttot, 6)
-        self.assertEqual(cfsbb.tsub, 6)
-        self.assertEqual(cfsbb.nactualcall, 0)
-        self.assertEqual(cfsbb.ncall, 2)
-
-    def test_aaab(self):
-        _timings = {"a_1": 13, "a_2": 10, "a_3": 6, "b_1": 1}
-        _yappi._set_test_timings(_timings)
-
-        self._ncall = 1
-
-        def a():
-            if self._ncall == 3:
-                b()
-                return
-            self._ncall += 1
-            a()
-
-        def b():
-            return
-
-        stats = utils.run_and_get_func_stats(a)
-        fsa = utils.find_stat_by_name(stats, 'a')
-        fsb = utils.find_stat_by_name(stats, 'b')
-        cfsaa = fsa.children[fsa]
-        cfsab = fsa.children[fsb]
-        self.assertEqual(fsa.ttot, 13)
-        self.assertEqual(fsa.tsub, 12)
-        self.assertEqual(fsb.ttot, 1)
-        self.assertEqual(fsb.tsub, 1)
-        self.assertEqual(cfsaa.ttot, 10)
-        self.assertEqual(cfsaa.tsub, 9)
-        self.assertEqual(cfsab.ttot, 1)
-        self.assertEqual(cfsab.tsub, 1)
-
-    def test_abab(self):
-        _timings = {"a_1": 13, "b_1": 10, "a_2": 6, "b_2": 1}
-        _yappi._set_test_timings(_timings)
-
-        self._ncall = 1
-
-        def a():
-            b()
-
-        def b():
-            if self._ncall == 2:
-                return
-            self._ncall += 1
-            a()
-
-        stats = utils.run_and_get_func_stats(a)
-        fsa = utils.find_stat_by_name(stats, 'a')
-        fsb = utils.find_stat_by_name(stats, 'b')
-        cfsab = fsa.children[fsb]
-        cfsba = fsb.children[fsa]
-        self.assertEqual(fsa.ttot, 13)
-        self.assertEqual(fsa.tsub, 8)
-        self.assertEqual(fsb.ttot, 10)
-        self.assertEqual(fsb.tsub, 5)
-        self.assertEqual(cfsab.ttot, 10)
-        self.assertEqual(cfsab.tsub, 5)
-        self.assertEqual(cfsab.ncall, 2)
-        self.assertEqual(cfsab.nactualcall, 1)
-        self.assertEqual(cfsba.ttot, 6)
-        self.assertEqual(cfsba.tsub, 5)
-
-
-if __name__ == '__main__':
-    #     import sys;sys.argv = ['', 'BasicUsage.test_run_as_script']
-    #     import sys;sys.argv = ['', 'MultithreadedScenarios.test_subsequent_profile']
-    unittest.main()
+import os
+import sys
+import time
+import threading
+import unittest
+import yappi
+import _yappi
+import tests.utils as utils
+import multiprocessing  # added to fix http://bugs.python.org/issue15881 for > Py2.6
+import subprocess
+
+_counter = 0
+
+
+class BasicUsage(utils.YappiUnitTestCase):
+
+    def test_callback_function_int_return_overflow(self):
+        # this test is just here to check if any errors are generated, as the err
+        # is printed in C side, I did not include it here. THere are ways to test
+        # this deterministically, I did not bother
+        import ctypes
+
+        def _unsigned_overflow_margin():
+            return 2**(ctypes.sizeof(ctypes.c_void_p) * 8) - 1
+
+        def foo():
+            pass
+
+        #with utils.captured_output() as (out, err):
+        yappi.set_context_id_callback(_unsigned_overflow_margin)
+        yappi.set_tag_callback(_unsigned_overflow_margin)
+        yappi.start()
+        foo()
+
+    def test_issue60(self):
+
+        def foo():
+            buf = bytearray()
+            buf += b't' * 200
+            view = memoryview(buf)[10:]
+            view = view.tobytes()
+            del buf[:10]  # this throws exception
+            return view
+
+        yappi.start(builtins=True)
+        foo()
+        self.assertTrue(
+            len(
+                yappi.get_func_stats(
+                    filter_callback=lambda x: yappi.
+                    func_matches(x, [memoryview.tobytes])
+                )
+            ) > 0
+        )
+        yappi.stop()
+
+    def test_issue54(self):
+
+        def _tag_cbk():
+            global _counter
+            _counter += 1
+            return _counter
+
+        def a():
+            pass
+
+        def b():
+            pass
+
+        yappi.set_tag_callback(_tag_cbk)
+        yappi.start()
+        a()
+        a()
+        a()
+        yappi.stop()
+        stats = yappi.get_func_stats()
+        self.assertEqual(stats.pop().ncall, 3)  # aggregated if no tag is given
+        stats = yappi.get_func_stats(tag=1)
+
+        for i in range(1, 3):
+            stats = yappi.get_func_stats(tag=i)
+            stats = yappi.get_func_stats(
+                tag=i, filter_callback=lambda x: yappi.func_matches(x, [a])
+            )
+
+            stat = stats.pop()
+            self.assertEqual(stat.ncall, 1)
+
+        yappi.set_tag_callback(None)
+        yappi.clear_stats()
+        yappi.start()
+        b()
+        b()
+        stats = yappi.get_func_stats()
+        self.assertEqual(len(stats), 1)
+        stat = stats.pop()
+        self.assertEqual(stat.ncall, 2)
+
+    def test_filter(self):
+
+        def a():
+            pass
+
+        def b():
+            a()
+
+        def c():
+            b()
+
+        _TCOUNT = 5
+
+        ts = []
+        yappi.start()
+        for i in range(_TCOUNT):
+            t = threading.Thread(target=c)
+            t.start()
+            ts.append(t)
+
+        for t in ts:
+            t.join()
+
+        yappi.stop()
+
+        ctx_ids = []
+        for tstat in yappi.get_thread_stats():
+            if tstat.name == '_MainThread':
+                main_ctx_id = tstat.id
+            else:
+                ctx_ids.append(tstat.id)
+
+        fstats = yappi.get_func_stats(filter={"ctx_id": 9})
+        self.assertTrue(fstats.empty())
+        fstats = yappi.get_func_stats(
+            filter={
+                "ctx_id": main_ctx_id,
+                "name": "c"
+            }
+        )  # main thread
+        self.assertTrue(fstats.empty())
+
+        for i in ctx_ids:
+            fstats = yappi.get_func_stats(
+                filter={
+                    "ctx_id": i,
+                    "name": "a",
+                    "ncall": 1
+                }
+            )
+            self.assertEqual(fstats.pop().ncall, 1)
+            fstats = yappi.get_func_stats(filter={"ctx_id": i, "name": "b"})
+            self.assertEqual(fstats.pop().ncall, 1)
+            fstats = yappi.get_func_stats(filter={"ctx_id": i, "name": "c"})
+            self.assertEqual(fstats.pop().ncall, 1)
+
+        yappi.clear_stats()
+        yappi.start(builtins=True)
+        time.sleep(0.1)
+        yappi.stop()
+        fstats = yappi.get_func_stats(filter={"module": "time"})
+        self.assertEqual(len(fstats), 1)
+
+        # invalid filters`
+        self.assertRaises(
+            Exception, yappi.get_func_stats, filter={'tag': "sss"}
+        )
+        self.assertRaises(
+            Exception, yappi.get_func_stats, filter={'ctx_id': "None"}
+        )
+
+    def test_filter_callback(self):
+
+        def a():
+            time.sleep(0.1)
+
+        def b():
+            a()
+
+        def c():
+            pass
+
+        def d():
+            pass
+
+        yappi.set_clock_type("wall")
+        yappi.start(builtins=True)
+        a()
+        b()
+        c()
+        d()
+        stats = yappi.get_func_stats(
+            filter_callback=lambda x: yappi.func_matches(x, [a, b])
+        )
+        #stats.print_all()
+        r1 = '''
+        tests/test_functionality.py:98 a      2      0.000000  0.200350  0.100175
+        tests/test_functionality.py:101 b     1      0.000000  0.120000  0.100197
+        '''
+        self.assert_traces_almost_equal(r1, stats)
+        self.assertEqual(len(stats), 2)
+        stats = yappi.get_func_stats(
+            filter_callback=lambda x: yappi.
+            module_matches(x, [sys.modules[__name__]])
+        )
+        r1 = '''
+        tests/test_functionality.py:98 a      2      0.000000  0.230130  0.115065
+        tests/test_functionality.py:101 b     1      0.000000  0.120000  0.109011
+        tests/test_functionality.py:104 c     1      0.000000  0.000002  0.000002
+        tests/test_functionality.py:107 d     1      0.000000  0.000001  0.000001
+        '''
+        self.assert_traces_almost_equal(r1, stats)
+        self.assertEqual(len(stats), 4)
+
+        stats = yappi.get_func_stats(
+            filter_callback=lambda x: yappi.func_matches(x, [time.sleep])
+        )
+        self.assertEqual(len(stats), 1)
+        r1 = '''
+        time.sleep                            2      0.206804  0.220000  0.103402
+        '''
+        self.assert_traces_almost_equal(r1, stats)
+
+    def test_print_formatting(self):
+
+        def a():
+            pass
+
+        def b():
+            a()
+
+        func_cols = {
+            1: ("name", 48),
+            0: ("ncall", 5),
+            2: ("tsub", 8),
+        }
+        thread_cols = {
+            1: ("name", 48),
+            0: ("ttot", 8),
+        }
+
+        yappi.start()
+        a()
+        b()
+        yappi.stop()
+        fs = yappi.get_func_stats()
+        cs = fs[1].children
+        ts = yappi.get_thread_stats()
+        #fs.print_all(out=sys.stderr, columns={1:("name", 70), })
+        #cs.print_all(out=sys.stderr, columns=func_cols)
+        #ts.print_all(out=sys.stderr, columns=thread_cols)
+        #cs.print_all(out=sys.stderr, columns={})
+
+        self.assertRaises(
+            yappi.YappiError, fs.print_all, columns={1: ("namee", 9)}
+        )
+        self.assertRaises(
+            yappi.YappiError, cs.print_all, columns={1: ("dd", 0)}
+        )
+        self.assertRaises(
+            yappi.YappiError, ts.print_all, columns={1: ("tidd", 0)}
+        )
+
+    def test_get_clock(self):
+        yappi.set_clock_type('cpu')
+        self.assertEqual('cpu', yappi.get_clock_type())
+        clock_info = yappi.get_clock_info()
+        self.assertTrue('api' in clock_info)
+        self.assertTrue('resolution' in clock_info)
+
+        yappi.set_clock_type('wall')
+        self.assertEqual('wall', yappi.get_clock_type())
+
+        t0 = yappi.get_clock_time()
+        time.sleep(0.1)
+        duration = yappi.get_clock_time() - t0
+        self.assertTrue(0.05 < duration < 0.3)
+
+    def test_profile_decorator(self):
+
+        def aggregate(func, stats):
+            fname = "tests/%s.profile" % (func.__name__)
+            try:
+                stats.add(fname)
+            except IOError:
+                pass
+            stats.save(fname)
+            raise Exception("messing around")
+
+        @yappi.profile(return_callback=aggregate)
+        def a(x, y):
+            if x + y == 25:
+                raise Exception("")
+            return x + y
+
+        def b():
+            pass
+
+        try:
+            os.remove(
+                "tests/a.profile"
+            )  # remove the one from prev test, if available
+        except:
+            pass
+
+        # global profile is on to mess things up
+        yappi.start()
+        b()
+
+        # assert functionality and call function at same time
+        try:
+            self.assertEqual(a(1, 2), 3)
+        except:
+            pass
+        try:
+            self.assertEqual(a(2, 5), 7)
+        except:
+            pass
+        try:
+            a(4, 21)
+        except:
+            pass
+        stats = yappi.get_func_stats().add("tests/a.profile")
+        fsa = utils.find_stat_by_name(stats, 'a')
+        self.assertEqual(fsa.ncall, 3)
+        self.assertEqual(len(stats), 1)  # b() should be cleared out.
+
+        @yappi.profile(return_callback=aggregate)
+        def count_down_rec(n):
+            if n == 0:
+                return
+            count_down_rec(n - 1)
+
+        try:
+            os.remove(
+                "tests/count_down_rec.profile"
+            )  # remove the one from prev test, if available
+        except:
+            pass
+
+        try:
+            count_down_rec(4)
+        except:
+            pass
+        try:
+            count_down_rec(3)
+        except:
+            pass
+
+        stats = yappi.YFuncStats("tests/count_down_rec.profile")
+        fsrec = utils.find_stat_by_name(stats, 'count_down_rec')
+        self.assertEqual(fsrec.ncall, 9)
+        self.assertEqual(fsrec.nactualcall, 2)
+
+    def test_strip_dirs(self):
+
+        def a():
+            pass
+
+        stats = utils.run_and_get_func_stats(a, )
+        stats.strip_dirs()
+        fsa = utils.find_stat_by_name(stats, "a")
+        self.assertEqual(fsa.module, os.path.basename(fsa.module))
+
+    @unittest.skipIf(os.name == "nt", "do not run on Windows")
+    def test_run_as_script(self):
+        import re
+        p = subprocess.Popen(
+            ['yappi', os.path.join('./tests', 'run_as_script.py')],
+            stdout=subprocess.PIPE
+        )
+        out, err = p.communicate()
+        self.assertEqual(p.returncode, 0)
+        func_stats, thread_stats = re.split(
+            b'name\\s+id\\s+tid\\s+ttot\\s+scnt\\s*\n', out
+        )
+        self.assertTrue(b'FancyThread' in thread_stats)
+
+    def test_yappi_overhead(self):
+        LOOP_COUNT = 100000
+
+        def a():
+            pass
+
+        def b():
+            for i in range(LOOP_COUNT):
+                a()
+
+        t0 = time.time()
+        yappi.start()
+        b()
+        yappi.stop()
+        time_with_yappi = time.time() - t0
+        t0 = time.time()
+        b()
+        time_without_yappi = time.time() - t0
+        if time_without_yappi == 0:
+            time_without_yappi = 0.000001
+
+        # in latest v0.82, I calculated this as close to "7.0" in my machine.
+        # however, %83 of this overhead is coming from tickcount(). The other %17
+        # seems to have been evenly distributed to the internal bookkeeping
+        # structures/algorithms which seems acceptable. Note that our test only
+        # tests one function being profiled at-a-time in a short interval.
+        # profiling high number of functions in a small time
+        # is a different beast, (which is pretty unlikely in most applications)
+        # So as a conclusion: I cannot see any optimization window for Yappi that
+        # is worth implementing as we will only optimize %17 of the time.
+        sys.stderr.write("\r\nYappi puts %0.1f times overhead to the profiled application in average.\r\n" % \
+            (time_with_yappi / time_without_yappi))
+
+    def test_clear_stats_while_running(self):
+
+        def a():
+            pass
+
+        yappi.start()
+        a()
+        yappi.clear_stats()
+        a()
+        stats = yappi.get_func_stats()
+        fsa = utils.find_stat_by_name(stats, 'a')
+        self.assertEqual(fsa.ncall, 1)
+
+    def test_generator(self):
+
+        def _gen(n):
+            while (n > 0):
+                yield n
+                n -= 1
+
+        yappi.start()
+        for x in _gen(5):
+            pass
+        self.assertTrue(
+            yappi.convert2pstats(yappi.get_func_stats()) is not None
+        )
+
+    def test_slice_child_stats_and_strip_dirs(self):
+
+        def b():
+            for i in range(10000000):
+                pass
+
+        def a():
+            b()
+
+        yappi.start(builtins=True)
+        a()
+        stats = yappi.get_func_stats()
+        fsa = utils.find_stat_by_name(stats, 'a')
+        fsb = utils.find_stat_by_name(stats, 'b')
+        self.assertTrue(fsa.children[0:1] is not None)
+        prev_afullname = fsa.full_name
+        prev_bchildfullname = fsa.children[fsb].full_name
+        stats.strip_dirs()
+        self.assertTrue(len(prev_afullname) > len(fsa.full_name))
+        self.assertTrue(
+            len(prev_bchildfullname) > len(fsa.children[fsb].full_name)
+        )
+
+    def test_children_stat_functions(self):
+        _timings = {"a_1": 5, "b_1": 3, "c_1": 1}
+        _yappi._set_test_timings(_timings)
+
+        def b():
+            pass
+
+        def c():
+            pass
+
+        def a():
+            b()
+            c()
+
+        yappi.start()
+        a()
+        b()  # non-child call
+        c()  # non-child call
+        stats = yappi.get_func_stats()
+        fsa = utils.find_stat_by_name(stats, 'a')
+        childs_of_a = fsa.children.get().sort("tavg", "desc")
+        prev_item = None
+        for item in childs_of_a:
+            if prev_item:
+                self.assertTrue(prev_item.tavg > item.tavg)
+            prev_item = item
+        childs_of_a.sort("name", "desc")
+        prev_item = None
+        for item in childs_of_a:
+            if prev_item:
+                self.assertTrue(prev_item.name > item.name)
+            prev_item = item
+        childs_of_a.clear()
+        self.assertTrue(childs_of_a.empty())
+
+    def test_no_stats_different_clock_type_load(self):
+
+        def a():
+            pass
+
+        yappi.start()
+        a()
+        yappi.stop()
+        yappi.get_func_stats().save("tests/ystats1.ys")
+        yappi.clear_stats()
+        yappi.set_clock_type("WALL")
+        yappi.start()
+        yappi.stop()
+        stats = yappi.get_func_stats().add("tests/ystats1.ys")
+        fsa = utils.find_stat_by_name(stats, 'a')
+        self.assertTrue(fsa is not None)
+
+    def test_subsequent_profile(self):
+        _timings = {"a_1": 1, "b_1": 1}
+        _yappi._set_test_timings(_timings)
+
+        def a():
+            pass
+
+        def b():
+            pass
+
+        yappi.start()
+        a()
+        yappi.stop()
+        yappi.start()
+        b()
+        yappi.stop()
+        stats = yappi.get_func_stats()
+        fsa = utils.find_stat_by_name(stats, 'a')
+        fsb = utils.find_stat_by_name(stats, 'b')
+        self.assertTrue(fsa is not None)
+        self.assertTrue(fsb is not None)
+        self.assertEqual(fsa.ttot, 1)
+        self.assertEqual(fsb.ttot, 1)
+
+    def test_lambda(self):
+        f = lambda: time.sleep(0.3)
+        yappi.set_clock_type("wall")
+        yappi.start()
+        f()
+        stats = yappi.get_func_stats()
+        fsa = utils.find_stat_by_name(stats, '<lambda>')
+        self.assertTrue(fsa.ttot > 0.1)
+
+    def test_module_stress(self):
+        self.assertEqual(yappi.is_running(), False)
+
+        yappi.start()
+        yappi.clear_stats()
+        self.assertRaises(_yappi.error, yappi.set_clock_type, "wall")
+
+        yappi.stop()
+        yappi.clear_stats()
+        yappi.set_clock_type("cpu")
+        self.assertRaises(yappi.YappiError, yappi.set_clock_type, "dummy")
+        self.assertEqual(yappi.is_running(), False)
+        yappi.clear_stats()
+        yappi.clear_stats()
+
+    def test_stat_sorting(self):
+        _timings = {"a_1": 13, "b_1": 10, "a_2": 6, "b_2": 1}
+        _yappi._set_test_timings(_timings)
+
+        self._ncall = 1
+
+        def a():
+            b()
+
+        def b():
+            if self._ncall == 2:
+                return
+            self._ncall += 1
+            a()
+
+        stats = utils.run_and_get_func_stats(a)
+        stats = stats.sort("totaltime", "desc")
+        prev_stat = None
+        for stat in stats:
+            if prev_stat:
+                self.assertTrue(prev_stat.ttot >= stat.ttot)
+            prev_stat = stat
+        stats = stats.sort("totaltime", "asc")
+        prev_stat = None
+        for stat in stats:
+            if prev_stat:
+                self.assertTrue(prev_stat.ttot <= stat.ttot)
+            prev_stat = stat
+        stats = stats.sort("avgtime", "asc")
+        prev_stat = None
+        for stat in stats:
+            if prev_stat:
+                self.assertTrue(prev_stat.tavg <= stat.tavg)
+            prev_stat = stat
+        stats = stats.sort("name", "asc")
+        prev_stat = None
+        for stat in stats:
+            if prev_stat:
+                self.assertTrue(prev_stat.name <= stat.name)
+            prev_stat = stat
+        stats = stats.sort("subtime", "asc")
+        prev_stat = None
+        for stat in stats:
+            if prev_stat:
+                self.assertTrue(prev_stat.tsub <= stat.tsub)
+            prev_stat = stat
+
+        self.assertRaises(
+            yappi.YappiError, stats.sort, "invalid_func_sorttype_arg"
+        )
+        self.assertRaises(
+            yappi.YappiError, stats.sort, "totaltime",
+            "invalid_func_sortorder_arg"
+        )
+
+    def test_start_flags(self):
+        self.assertEqual(_yappi._get_start_flags(), None)
+        yappi.start()
+
+        def a():
+            pass
+
+        a()
+        self.assertEqual(_yappi._get_start_flags()["profile_builtins"], 0)
+        self.assertEqual(_yappi._get_start_flags()["profile_multicontext"], 1)
+        self.assertEqual(len(yappi.get_thread_stats()), 1)
+
+    def test_builtin_profiling(self):
+
+        def a():
+            time.sleep(0.4)  # is a builtin function
+
+        yappi.set_clock_type('wall')
+
+        yappi.start(builtins=True)
+        a()
+        stats = yappi.get_func_stats()
+        fsa = utils.find_stat_by_name(stats, 'sleep')
+        self.assertTrue(fsa is not None)
+        self.assertTrue(fsa.ttot > 0.3)
+        yappi.stop()
+        yappi.clear_stats()
+
+        def a():
+            pass
+
+        yappi.start()
+        t = threading.Thread(target=a)
+        t.start()
+        t.join()
+        stats = yappi.get_func_stats()
+
+    def test_singlethread_profiling(self):
+        yappi.set_clock_type('wall')
+
+        def a():
+            time.sleep(0.2)
+
+        class Worker1(threading.Thread):
+
+            def a(self):
+                time.sleep(0.3)
+
+            def run(self):
+                self.a()
+
+        yappi.start(profile_threads=False)
+
+        c = Worker1()
+        c.start()
+        c.join()
+        a()
+        stats = yappi.get_func_stats()
+        fsa1 = utils.find_stat_by_name(stats, 'Worker1.a')
+        fsa2 = utils.find_stat_by_name(stats, 'a')
+        self.assertTrue(fsa1 is None)
+        self.assertTrue(fsa2 is not None)
+        self.assertTrue(fsa2.ttot > 0.1)
+
+    def test_run(self):
+
+        def profiled():
+            pass
+
+        yappi.clear_stats()
+        try:
+            with yappi.run():
+                profiled()
+            stats = yappi.get_func_stats()
+        finally:
+            yappi.clear_stats()
+
+        self.assertIsNotNone(utils.find_stat_by_name(stats, 'profiled'))
+
+    def test_run_recursive(self):
+
+        def profiled():
+            pass
+
+        def not_profiled():
+            pass
+
+        yappi.clear_stats()
+        try:
+            with yappi.run():
+                with yappi.run():
+                    profiled()
+                # Profiling stopped here
+                not_profiled()
+            stats = yappi.get_func_stats()
+        finally:
+            yappi.clear_stats()
+
+        self.assertIsNotNone(utils.find_stat_by_name(stats, 'profiled'))
+        self.assertIsNone(utils.find_stat_by_name(stats, 'not_profiled'))
+
+
+class StatSaveScenarios(utils.YappiUnitTestCase):
+
+    def test_pstats_conversion(self):
+
+        def pstat_id(fs):
+            return (fs.module, fs.lineno, fs.name)
+
+        def a():
+            d()
+
+        def b():
+            d()
+
+        def c():
+            pass
+
+        def d():
+            pass
+
+        _timings = {"a_1": 12, "b_1": 7, "c_1": 5, "d_1": 2}
+        _yappi._set_test_timings(_timings)
+        stats = utils.run_and_get_func_stats(a, )
+        stats.strip_dirs()
+        stats.save("tests/a1.pstats", type="pstat")
+        fsa_pid = pstat_id(utils.find_stat_by_name(stats, "a"))
+        fsd_pid = pstat_id(utils.find_stat_by_name(stats, "d"))
+        yappi.clear_stats()
+        _yappi._set_test_timings(_timings)
+        stats = utils.run_and_get_func_stats(a, )
+        stats.strip_dirs()
+        stats.save("tests/a2.pstats", type="pstat")
+        yappi.clear_stats()
+        _yappi._set_test_timings(_timings)
+        stats = utils.run_and_get_func_stats(b, )
+        stats.strip_dirs()
+        stats.save("tests/b1.pstats", type="pstat")
+        fsb_pid = pstat_id(utils.find_stat_by_name(stats, "b"))
+        yappi.clear_stats()
+        _yappi._set_test_timings(_timings)
+        stats = utils.run_and_get_func_stats(c, )
+        stats.strip_dirs()
+        stats.save("tests/c1.pstats", type="pstat")
+        fsc_pid = pstat_id(utils.find_stat_by_name(stats, "c"))
+
+        # merge saved stats and check pstats values are correct
+        import pstats
+        p = pstats.Stats(
+            'tests/a1.pstats', 'tests/a2.pstats', 'tests/b1.pstats',
+            'tests/c1.pstats'
+        )
+        p.strip_dirs()
+        # ct = ttot, tt = tsub
+        (cc, nc, tt, ct, callers) = p.stats[fsa_pid]
+        self.assertEqual(cc, nc, 2)
+        self.assertEqual(tt, 20)
+        self.assertEqual(ct, 24)
+        (cc, nc, tt, ct, callers) = p.stats[fsd_pid]
+        self.assertEqual(cc, nc, 3)
+        self.assertEqual(tt, 6)
+        self.assertEqual(ct, 6)
+        self.assertEqual(len(callers), 2)
+        (cc, nc, tt, ct) = callers[fsa_pid]
+        self.assertEqual(cc, nc, 2)
+        self.assertEqual(tt, 4)
+        self.assertEqual(ct, 4)
+        (cc, nc, tt, ct) = callers[fsb_pid]
+        self.assertEqual(cc, nc, 1)
+        self.assertEqual(tt, 2)
+        self.assertEqual(ct, 2)
+
+    def test_merge_stats(self):
+        _timings = {
+            "a_1": 15,
+            "b_1": 14,
+            "c_1": 12,
+            "d_1": 10,
+            "e_1": 9,
+            "f_1": 7,
+            "g_1": 6,
+            "h_1": 5,
+            "i_1": 1
+        }
+        _yappi._set_test_timings(_timings)
+
+        def a():
+            b()
+
+        def b():
+            c()
+
+        def c():
+            d()
+
+        def d():
+            e()
+
+        def e():
+            f()
+
+        def f():
+            g()
+
+        def g():
+            h()
+
+        def h():
+            i()
+
+        def i():
+            pass
+
+        yappi.start()
+        a()
+        a()
+        yappi.stop()
+        stats = yappi.get_func_stats()
+        self.assertRaises(
+            NotImplementedError, stats.save, "", "INVALID_SAVE_TYPE"
+        )
+        stats.save("tests/ystats2.ys")
+        yappi.clear_stats()
+        _yappi._set_test_timings(_timings)
+        yappi.start()
+        a()
+        stats = yappi.get_func_stats().add("tests/ystats2.ys")
+        fsa = utils.find_stat_by_name(stats, "a")
+        fsb = utils.find_stat_by_name(stats, "b")
+        fsc = utils.find_stat_by_name(stats, "c")
+        fsd = utils.find_stat_by_name(stats, "d")
+        fse = utils.find_stat_by_name(stats, "e")
+        fsf = utils.find_stat_by_name(stats, "f")
+        fsg = utils.find_stat_by_name(stats, "g")
+        fsh = utils.find_stat_by_name(stats, "h")
+        fsi = utils.find_stat_by_name(stats, "i")
+        self.assertEqual(fsa.ttot, 45)
+        self.assertEqual(fsa.ncall, 3)
+        self.assertEqual(fsa.nactualcall, 3)
+        self.assertEqual(fsa.tsub, 3)
+        self.assertEqual(fsa.children[fsb].ttot, fsb.ttot)
+        self.assertEqual(fsa.children[fsb].tsub, fsb.tsub)
+        self.assertEqual(fsb.children[fsc].ttot, fsc.ttot)
+        self.assertEqual(fsb.children[fsc].tsub, fsc.tsub)
+        self.assertEqual(fsc.tsub, 6)
+        self.assertEqual(fsc.children[fsd].ttot, fsd.ttot)
+        self.assertEqual(fsc.children[fsd].tsub, fsd.tsub)
+        self.assertEqual(fsd.children[fse].ttot, fse.ttot)
+        self.assertEqual(fsd.children[fse].tsub, fse.tsub)
+        self.assertEqual(fse.children[fsf].ttot, fsf.ttot)
+        self.assertEqual(fse.children[fsf].tsub, fsf.tsub)
+        self.assertEqual(fsf.children[fsg].ttot, fsg.ttot)
+        self.assertEqual(fsf.children[fsg].tsub, fsg.tsub)
+        self.assertEqual(fsg.ttot, 18)
+        self.assertEqual(fsg.tsub, 3)
+        self.assertEqual(fsg.children[fsh].ttot, fsh.ttot)
+        self.assertEqual(fsg.children[fsh].tsub, fsh.tsub)
+        self.assertEqual(fsh.ttot, 15)
+        self.assertEqual(fsh.tsub, 12)
+        self.assertEqual(fsh.tavg, 5)
+        self.assertEqual(fsh.children[fsi].ttot, fsi.ttot)
+        self.assertEqual(fsh.children[fsi].tsub, fsi.tsub)
+        #stats.debug_print()
+
+    def test_merge_multithreaded_stats(self):
+        import _yappi
+        timings = {"a_1": 2, "b_1": 1}
+        _yappi._set_test_timings(timings)
+
+        def a():
+            pass
+
+        def b():
+            pass
+
+        yappi.start()
+        t = threading.Thread(target=a)
+        t.start()
+        t.join()
+        t = threading.Thread(target=b)
+        t.start()
+        t.join()
+        yappi.get_func_stats().save("tests/ystats1.ys")
+        yappi.clear_stats()
+        _yappi._set_test_timings(timings)
+        self.assertEqual(len(yappi.get_func_stats()), 0)
+        self.assertEqual(len(yappi.get_thread_stats()), 1)
+        t = threading.Thread(target=a)
+        t.start()
+        t.join()
+
+        self.assertEqual(_yappi._get_start_flags()["profile_builtins"], 0)
+        self.assertEqual(_yappi._get_start_flags()["profile_multicontext"], 1)
+        yappi.get_func_stats().save("tests/ystats2.ys")
+
+        stats = yappi.YFuncStats([
+            "tests/ystats1.ys",
+            "tests/ystats2.ys",
+        ])
+        fsa = utils.find_stat_by_name(stats, "a")
+        fsb = utils.find_stat_by_name(stats, "b")
+        self.assertEqual(fsa.ncall, 2)
+        self.assertEqual(fsb.ncall, 1)
+        self.assertEqual(fsa.tsub, fsa.ttot, 4)
+        self.assertEqual(fsb.tsub, fsb.ttot, 1)
+
+    def test_merge_load_different_clock_types(self):
+        yappi.start(builtins=True)
+
+        def a():
+            b()
+
+        def b():
+            c()
+
+        def c():
+            pass
+
+        t = threading.Thread(target=a)
+        t.start()
+        t.join()
+        yappi.get_func_stats().sort("name", "asc").save("tests/ystats1.ys")
+        yappi.stop()
+        yappi.clear_stats()
+        yappi.start(builtins=False)
+        t = threading.Thread(target=a)
+        t.start()
+        t.join()
+        yappi.get_func_stats().save("tests/ystats2.ys")
+        yappi.stop()
+        self.assertRaises(_yappi.error, yappi.set_clock_type, "wall")
+        yappi.clear_stats()
+        yappi.set_clock_type("wall")
+        yappi.start()
+        t = threading.Thread(target=a)
+        t.start()
+        t.join()
+        yappi.get_func_stats().save("tests/ystats3.ys")
+        self.assertRaises(
+            yappi.YappiError,
+            yappi.YFuncStats().add("tests/ystats1.ys").add, "tests/ystats3.ys"
+        )
+        stats = yappi.YFuncStats(["tests/ystats1.ys",
+                                  "tests/ystats2.ys"]).sort("name")
+        fsa = utils.find_stat_by_name(stats, "a")
+        fsb = utils.find_stat_by_name(stats, "b")
+        fsc = utils.find_stat_by_name(stats, "c")
+        self.assertEqual(fsa.ncall, 2)
+        self.assertEqual(fsa.ncall, fsb.ncall, fsc.ncall)
+
+    def test_merge_aabab_aabbc(self):
+        _timings = {
+            "a_1": 15,
+            "a_2": 14,
+            "b_1": 12,
+            "a_3": 10,
+            "b_2": 9,
+            "c_1": 4
+        }
+        _yappi._set_test_timings(_timings)
+
+        def a():
+            if self._ncall == 1:
+                self._ncall += 1
+                a()
+            elif self._ncall == 5:
+                self._ncall += 1
+                a()
+            else:
+                b()
+
+        def b():
+            if self._ncall == 2:
+                self._ncall += 1
+                a()
+            elif self._ncall == 6:
+                self._ncall += 1
+                b()
+            elif self._ncall == 7:
+                c()
+            else:
+                return
+
+        def c():
+            pass
+
+        self._ncall = 1
+        stats = utils.run_and_get_func_stats(a, )
+        stats.save("tests/ystats1.ys")
+        yappi.clear_stats()
+        _yappi._set_test_timings(_timings)
+        #stats.print_all()
+
+        self._ncall = 5
+        stats = utils.run_and_get_func_stats(a, )
+        stats.save("tests/ystats2.ys")
+
+        #stats.print_all()
+
+        def a():  # same name but another function(code object)
+            pass
+
+        yappi.start()
+        a()
+        stats = yappi.get_func_stats().add(
+            ["tests/ystats1.ys", "tests/ystats2.ys"]
+        )
+        #stats.print_all()
+        self.assertEqual(len(stats), 4)
+
+        fsa = None
+        for stat in stats:
+            if stat.name == "a" and stat.ttot == 45:
+                fsa = stat
+                break
+        self.assertTrue(fsa is not None)
+
+        self.assertEqual(fsa.ncall, 7)
+        self.assertEqual(fsa.nactualcall, 3)
+        self.assertEqual(fsa.ttot, 45)
+        self.assertEqual(fsa.tsub, 10)
+        fsb = utils.find_stat_by_name(stats, "b")
+        fsc = utils.find_stat_by_name(stats, "c")
+        self.assertEqual(fsb.ncall, 6)
+        self.assertEqual(fsb.nactualcall, 3)
+        self.assertEqual(fsb.ttot, 36)
+        self.assertEqual(fsb.tsub, 27)
+        self.assertEqual(fsb.tavg, 6)
+        self.assertEqual(fsc.ttot, 8)
+        self.assertEqual(fsc.tsub, 8)
+        self.assertEqual(fsc.tavg, 4)
+        self.assertEqual(fsc.nactualcall, fsc.ncall, 2)
+
+
+class MultithreadedScenarios(utils.YappiUnitTestCase):
+
+    def test_issue_32(self):
+        '''
+        Start yappi from different thread and we get Internal Error(15) as
+        the current_ctx_id() called while enumerating the threads in start()
+        and as it does not swap to the enumerated ThreadState* the THreadState_GetDict()
+        returns wrong object and thus sets an invalid id for the _ctx structure.
+
+        When this issue happens multiple Threads have same tid as the internal ts_ptr
+        will be same for different contexts. So, let's see if that happens
+        '''
+
+        def foo():
+            time.sleep(0.2)
+
+        def bar():
+            time.sleep(0.1)
+
+        def thread_func():
+            yappi.set_clock_type("wall")
+            yappi.start()
+
+            bar()
+
+        t = threading.Thread(target=thread_func)
+        t.start()
+        t.join()
+
+        foo()
+
+        yappi.stop()
+
+        thread_ids = set()
+        for tstat in yappi.get_thread_stats():
+            self.assertTrue(tstat.tid not in thread_ids)
+            thread_ids.add(tstat.tid)
+
+    def test_subsequent_profile(self):
+        WORKER_COUNT = 5
+
+        def a():
+            pass
+
+        def b():
+            pass
+
+        def c():
+            pass
+
+        _timings = {
+            "a_1": 3,
+            "b_1": 2,
+            "c_1": 1,
+        }
+
+        yappi.start()
+
+        def g():
+            pass
+
+        g()
+        yappi.stop()
+        yappi.clear_stats()
+        _yappi._set_test_timings(_timings)
+        yappi.start()
+
+        _dummy = []
+        for i in range(WORKER_COUNT):
+            t = threading.Thread(target=a)
+            t.start()
+            t.join()
+        for i in range(WORKER_COUNT):
+            t = threading.Thread(target=b)
+            t.start()
+            _dummy.append(t)
+            t.join()
+        for i in range(WORKER_COUNT):
+            t = threading.Thread(target=a)
+            t.start()
+            t.join()
+        for i in range(WORKER_COUNT):
+            t = threading.Thread(target=c)
+            t.start()
+            t.join()
+        yappi.stop()
+        yappi.start()
+
+        def f():
+            pass
+
+        f()
+        stats = yappi.get_func_stats()
+        fsa = utils.find_stat_by_name(stats, 'a')
+        fsb = utils.find_stat_by_name(stats, 'b')
+        fsc = utils.find_stat_by_name(stats, 'c')
+        self.assertEqual(fsa.ncall, 10)
+        self.assertEqual(fsb.ncall, 5)
+        self.assertEqual(fsc.ncall, 5)
+        self.assertEqual(fsa.ttot, fsa.tsub, 30)
+        self.assertEqual(fsb.ttot, fsb.tsub, 10)
+        self.assertEqual(fsc.ttot, fsc.tsub, 5)
+
+        # MACOSx optimizes by only creating one worker thread
+        self.assertTrue(len(yappi.get_thread_stats()) >= 2)
+
+    def test_basic(self):
+        yappi.set_clock_type('wall')
+
+        def dummy():
+            pass
+
+        def a():
+            time.sleep(0.2)
+
+        class Worker1(threading.Thread):
+
+            def a(self):
+                time.sleep(0.3)
+
+            def run(self):
+                self.a()
+
+        yappi.start(builtins=False, profile_threads=True)
+
+        c = Worker1()
+        c.start()
+        c.join()
+        a()
+        stats = yappi.get_func_stats()
+        fsa1 = utils.find_stat_by_name(stats, 'Worker1.a')
+        fsa2 = utils.find_stat_by_name(stats, 'a')
+        self.assertTrue(fsa1 is not None)
+        self.assertTrue(fsa2 is not None)
+        self.assertTrue(fsa1.ttot > 0.2)
+        self.assertTrue(fsa2.ttot > 0.1)
+        tstats = yappi.get_thread_stats()
+        self.assertEqual(len(tstats), 2)
+        tsa = utils.find_stat_by_name(tstats, 'Worker1')
+        tsm = utils.find_stat_by_name(tstats, '_MainThread')
+        dummy()  # call dummy to force ctx name to be retrieved again.
+        self.assertTrue(tsa is not None)
+        # TODO: I put dummy() to fix below, remove the comments after a while.
+        self.assertTrue( # FIX: I see this fails sometimes?
+            tsm is not None,
+            'Could not find "_MainThread". Found: %s' % (', '.join(utils.get_stat_names(tstats))))
+
+    def test_ctx_stats(self):
+        from threading import Thread
+        DUMMY_WORKER_COUNT = 5
+        yappi.start()
+
+        class DummyThread(Thread):
+            pass
+
+        def dummy():
+            pass
+
+        def dummy_worker():
+            pass
+
+        for i in range(DUMMY_WORKER_COUNT):
+            t = DummyThread(target=dummy_worker)
+            t.start()
+            t.join()
+        yappi.stop()
+        stats = yappi.get_thread_stats()
+        tsa = utils.find_stat_by_name(stats, "DummyThread")
+        self.assertTrue(tsa is not None)
+        yappi.clear_stats()
+        time.sleep(1.0)
+        _timings = {
+            "a_1": 6,
+            "b_1": 5,
+            "c_1": 3,
+            "d_1": 1,
+            "a_2": 4,
+            "b_2": 3,
+            "c_2": 2,
+            "d_2": 1
+        }
+        _yappi._set_test_timings(_timings)
+
+        class Thread1(Thread):
+            pass
+
+        class Thread2(Thread):
+            pass
+
+        def a():
+            b()
+
+        def b():
+            c()
+
+        def c():
+            d()
+
+        def d():
+            time.sleep(0.6)
+
+        yappi.set_clock_type("wall")
+        yappi.start()
+        t1 = Thread1(target=a)
+        t1.start()
+        t2 = Thread2(target=a)
+        t2.start()
+        t1.join()
+        t2.join()
+        stats = yappi.get_thread_stats()
+
+        # the fist clear_stats clears the context table?
+        tsa = utils.find_stat_by_name(stats, "DummyThread")
+        self.assertTrue(tsa is None)
+
+        tst1 = utils.find_stat_by_name(stats, "Thread1")
+        tst2 = utils.find_stat_by_name(stats, "Thread2")
+        tsmain = utils.find_stat_by_name(stats, "_MainThread")
+        dummy()  # call dummy to force ctx name to be retrieved again.
+        self.assertTrue(len(stats) == 3)
+        self.assertTrue(tst1 is not None)
+        self.assertTrue(tst2 is not None)
+        # TODO: I put dummy() to fix below, remove the comments after a while.
+        self.assertTrue( # FIX: I see this fails sometimes
+            tsmain is not None,
+            'Could not find "_MainThread". Found: %s' % (', '.join(utils.get_stat_names(stats))))
+        self.assertTrue(1.0 > tst2.ttot >= 0.5)
+        self.assertTrue(1.0 > tst1.ttot >= 0.5)
+
+        # test sorting of the ctx stats
+        stats = stats.sort("totaltime", "desc")
+        prev_stat = None
+        for stat in stats:
+            if prev_stat:
+                self.assertTrue(prev_stat.ttot >= stat.ttot)
+            prev_stat = stat
+        stats = stats.sort("totaltime", "asc")
+        prev_stat = None
+        for stat in stats:
+            if prev_stat:
+                self.assertTrue(prev_stat.ttot <= stat.ttot)
+            prev_stat = stat
+        stats = stats.sort("schedcount", "desc")
+        prev_stat = None
+        for stat in stats:
+            if prev_stat:
+                self.assertTrue(prev_stat.sched_count >= stat.sched_count)
+            prev_stat = stat
+        stats = stats.sort("name", "desc")
+        prev_stat = None
+        for stat in stats:
+            if prev_stat:
+                self.assertTrue(prev_stat.name.lower() >= stat.name.lower())
+            prev_stat = stat
+        self.assertRaises(
+            yappi.YappiError, stats.sort, "invalid_thread_sorttype_arg"
+        )
+        self.assertRaises(
+            yappi.YappiError, stats.sort, "invalid_thread_sortorder_arg"
+        )
+
+    def test_ctx_stats_cpu(self):
+
+        def get_thread_name():
+            try:
+                return threading.current_thread().name
+            except AttributeError:
+                return "Anonymous"
+
+        def burn_cpu(sec):
+            t0 = yappi.get_clock_time()
+            elapsed = 0
+            while (elapsed < sec):
+                for _ in range(1000):
+                    pass
+                elapsed = yappi.get_clock_time() - t0
+
+        def test():
+
+            ts = []
+            for i in (0.01, 0.05, 0.1):
+                t = threading.Thread(target=burn_cpu, args=(i, ))
+                t.name = "burn_cpu-%s" % str(i)
+                t.start()
+                ts.append(t)
+            for t in ts:
+                t.join()
+
+        yappi.set_clock_type("cpu")
+        yappi.set_context_name_callback(get_thread_name)
+
+        yappi.start()
+
+        test()
+
+        yappi.stop()
+
+        tstats = yappi.get_thread_stats()
+        r1 = '''
+        burn_cpu-0.1      3      123145356058624  0.100105  8
+        burn_cpu-0.05     2      123145361313792  0.050149  8
+        burn_cpu-0.01     1      123145356058624  0.010127  2
+        MainThread        0      4321620864       0.001632  6
+        '''
+        self.assert_ctx_stats_almost_equal(r1, tstats)
+
+    def test_producer_consumer_with_queues(self):
+        # we currently just stress yappi, no functionality test is done here.
+        yappi.start()
+        if utils.is_py3x():
+            from queue import Queue
+        else:
+            from Queue import Queue
+        from threading import Thread
+        WORKER_THREAD_COUNT = 50
+        WORK_ITEM_COUNT = 2000
+
+        def worker():
+            while True:
+                item = q.get()
+                # do the work with item
+                q.task_done()
+
+        q = Queue()
+        for i in range(WORKER_THREAD_COUNT):
+            t = Thread(target=worker)
+            t.daemon = True
+            t.start()
+
+        for item in range(WORK_ITEM_COUNT):
+            q.put(item)
+        q.join()  # block until all tasks are done
+        #yappi.get_func_stats().sort("callcount").print_all()
+        yappi.stop()
+
+    def test_temporary_lock_waiting(self):
+        yappi.start()
+        _lock = threading.Lock()
+
+        def worker():
+            _lock.acquire()
+            try:
+                time.sleep(1.0)
+            finally:
+                _lock.release()
+
+        t1 = threading.Thread(target=worker)
+        t2 = threading.Thread(target=worker)
+        t1.start()
+        t2.start()
+        t1.join()
+        t2.join()
+        #yappi.get_func_stats().sort("callcount").print_all()
+        yappi.stop()
+
+    @unittest.skipIf(os.name != "posix", "requires Posix compliant OS")
+    def test_signals_with_blocking_calls(self):
+        import signal, os, time
+
+        # just to verify if signal is handled correctly and stats/yappi are not corrupted.
+        def handler(signum, frame):
+            raise Exception("Signal handler executed!")
+
+        yappi.start()
+        signal.signal(signal.SIGALRM, handler)
+        signal.alarm(1)
+        self.assertRaises(Exception, time.sleep, 2)
+        stats = yappi.get_func_stats()
+        fsh = utils.find_stat_by_name(stats, "handler")
+        self.assertTrue(fsh is not None)
+
+    @unittest.skipIf(not sys.version_info >= (3, 2), "requires Python 3.2")
+    def test_concurrent_futures(self):
+        yappi.start()
+        from concurrent.futures import ThreadPoolExecutor
+        with ThreadPoolExecutor(max_workers=5) as executor:
+            f = executor.submit(pow, 5, 2)
+            self.assertEqual(f.result(), 25)
+        time.sleep(1.0)
+        yappi.stop()
+
+    @unittest.skipIf(not sys.version_info >= (3, 2), "requires Python 3.2")
+    def test_barrier(self):
+        yappi.start()
+        b = threading.Barrier(2, timeout=1)
+
+        def worker():
+            try:
+                b.wait()
+            except threading.BrokenBarrierError:
+                pass
+            except Exception:
+                raise Exception("BrokenBarrierError not raised")
+
+        t1 = threading.Thread(target=worker)
+        t1.start()
+        #b.wait()
+        t1.join()
+        yappi.stop()
+
+
+class NonRecursiveFunctions(utils.YappiUnitTestCase):
+
+    def test_abcd(self):
+        _timings = {"a_1": 6, "b_1": 5, "c_1": 3, "d_1": 1}
+        _yappi._set_test_timings(_timings)
+
+        def a():
+            b()
+
+        def b():
+            c()
+
+        def c():
+            d()
+
+        def d():
+            pass
+
+        stats = utils.run_and_get_func_stats(a)
+        fsa = utils.find_stat_by_name(stats, 'a')
+        fsb = utils.find_stat_by_name(stats, 'b')
+        fsc = utils.find_stat_by_name(stats, 'c')
+        fsd = utils.find_stat_by_name(stats, 'd')
+        cfsab = fsa.children[fsb]
+        cfsbc = fsb.children[fsc]
+        cfscd = fsc.children[fsd]
+
+        self.assertEqual(fsa.ttot, 6)
+        self.assertEqual(fsa.tsub, 1)
+        self.assertEqual(fsb.ttot, 5)
+        self.assertEqual(fsb.tsub, 2)
+        self.assertEqual(fsc.ttot, 3)
+        self.assertEqual(fsc.tsub, 2)
+        self.assertEqual(fsd.ttot, 1)
+        self.assertEqual(fsd.tsub, 1)
+        self.assertEqual(cfsab.ttot, 5)
+        self.assertEqual(cfsab.tsub, 2)
+        self.assertEqual(cfsbc.ttot, 3)
+        self.assertEqual(cfsbc.tsub, 2)
+        self.assertEqual(cfscd.ttot, 1)
+        self.assertEqual(cfscd.tsub, 1)
+
+    def test_stop_in_middle(self):
+        _timings = {"a_1": 6, "b_1": 4}
+        _yappi._set_test_timings(_timings)
+
+        def a():
+            b()
+            yappi.stop()
+
+        def b():
+            time.sleep(0.2)
+
+        yappi.start()
+        a()
+        stats = yappi.get_func_stats()
+        fsa = utils.find_stat_by_name(stats, 'a')
+        fsb = utils.find_stat_by_name(stats, 'b')
+
+        self.assertEqual(fsa.ncall, 1)
+        self.assertEqual(fsa.nactualcall, 0)
+        self.assertEqual(fsa.ttot, 0)  # no call_leave called
+        self.assertEqual(fsa.tsub, 0)  # no call_leave called
+        self.assertEqual(fsb.ttot, 4)
+
+
+class RecursiveFunctions(utils.YappiUnitTestCase):
+
+    def test_fibonacci(self):
+
+        def fib(n):
+            if n > 1:
+                return fib(n - 1) + fib(n - 2)
+            else:
+                return n
+
+        stats = utils.run_and_get_func_stats(fib, 22)
+        fs = utils.find_stat_by_name(stats, 'fib')
+        self.assertEqual(fs.ncall, 57313)
+        self.assertEqual(fs.ttot, fs.tsub)
+
+    def test_abcadc(self):
+        _timings = {
+            "a_1": 20,
+            "b_1": 19,
+            "c_1": 17,
+            "a_2": 13,
+            "d_1": 12,
+            "c_2": 10,
+            "a_3": 5
+        }
+        _yappi._set_test_timings(_timings)
+
+        def a(n):
+            if n == 3:
+                return
+            if n == 1 + 1:
+                d(n)
+            else:
+                b(n)
+
+        def b(n):
+            c(n)
+
+        def c(n):
+            a(n + 1)
+
+        def d(n):
+            c(n)
+
+        stats = utils.run_and_get_func_stats(a, 1)
+        fsa = utils.find_stat_by_name(stats, 'a')
+        fsb = utils.find_stat_by_name(stats, 'b')
+        fsc = utils.find_stat_by_name(stats, 'c')
+        fsd = utils.find_stat_by_name(stats, 'd')
+        self.assertEqual(fsa.ncall, 3)
+        self.assertEqual(fsa.nactualcall, 1)
+        self.assertEqual(fsa.ttot, 20)
+        self.assertEqual(fsa.tsub, 7)
+        self.assertEqual(fsb.ttot, 19)
+        self.assertEqual(fsb.tsub, 2)
+        self.assertEqual(fsc.ttot, 17)
+        self.assertEqual(fsc.tsub, 9)
+        self.assertEqual(fsd.ttot, 12)
+        self.assertEqual(fsd.tsub, 2)
+        cfsca = fsc.children[fsa]
+        self.assertEqual(cfsca.nactualcall, 0)
+        self.assertEqual(cfsca.ncall, 2)
+        self.assertEqual(cfsca.ttot, 13)
+        self.assertEqual(cfsca.tsub, 6)
+
+    def test_aaaa(self):
+        _timings = {"d_1": 9, "d_2": 7, "d_3": 3, "d_4": 2}
+        _yappi._set_test_timings(_timings)
+
+        def d(n):
+            if n == 3:
+                return
+            d(n + 1)
+
+        stats = utils.run_and_get_func_stats(d, 0)
+        fsd = utils.find_stat_by_name(stats, 'd')
+        self.assertEqual(fsd.ncall, 4)
+        self.assertEqual(fsd.nactualcall, 1)
+        self.assertEqual(fsd.ttot, 9)
+        self.assertEqual(fsd.tsub, 9)
+        cfsdd = fsd.children[fsd]
+        self.assertEqual(cfsdd.ttot, 7)
+        self.assertEqual(cfsdd.tsub, 7)
+        self.assertEqual(cfsdd.ncall, 3)
+        self.assertEqual(cfsdd.nactualcall, 0)
+
+    def test_abcabc(self):
+        _timings = {
+            "a_1": 20,
+            "b_1": 19,
+            "c_1": 17,
+            "a_2": 13,
+            "b_2": 11,
+            "c_2": 9,
+            "a_3": 6
+        }
+        _yappi._set_test_timings(_timings)
+
+        def a(n):
+            if n == 3:
+                return
+            else:
+                b(n)
+
+        def b(n):
+            c(n)
+
+        def c(n):
+            a(n + 1)
+
+        stats = utils.run_and_get_func_stats(a, 1)
+        fsa = utils.find_stat_by_name(stats, 'a')
+        fsb = utils.find_stat_by_name(stats, 'b')
+        fsc = utils.find_stat_by_name(stats, 'c')
+        self.assertEqual(fsa.ncall, 3)
+        self.assertEqual(fsa.nactualcall, 1)
+        self.assertEqual(fsa.ttot, 20)
+        self.assertEqual(fsa.tsub, 9)
+        self.assertEqual(fsb.ttot, 19)
+        self.assertEqual(fsb.tsub, 4)
+        self.assertEqual(fsc.ttot, 17)
+        self.assertEqual(fsc.tsub, 7)
+        cfsab = fsa.children[fsb]
+        cfsbc = fsb.children[fsc]
+        cfsca = fsc.children[fsa]
+        self.assertEqual(cfsab.ttot, 19)
+        self.assertEqual(cfsab.tsub, 4)
+        self.assertEqual(cfsbc.ttot, 17)
+        self.assertEqual(cfsbc.tsub, 7)
+        self.assertEqual(cfsca.ttot, 13)
+        self.assertEqual(cfsca.tsub, 8)
+
+    def test_abcbca(self):
+        _timings = {"a_1": 10, "b_1": 9, "c_1": 7, "b_2": 4, "c_2": 2, "a_2": 1}
+        _yappi._set_test_timings(_timings)
+        self._ncall = 1
+
+        def a():
+            if self._ncall == 1:
+                b()
+            else:
+                return
+
+        def b():
+            c()
+
+        def c():
+            if self._ncall == 1:
+                self._ncall += 1
+                b()
+            else:
+                a()
+
+        stats = utils.run_and_get_func_stats(a)
+        fsa = utils.find_stat_by_name(stats, 'a')
+        fsb = utils.find_stat_by_name(stats, 'b')
+        fsc = utils.find_stat_by_name(stats, 'c')
+        cfsab = fsa.children[fsb]
+        cfsbc = fsb.children[fsc]
+        cfsca = fsc.children[fsa]
+        self.assertEqual(fsa.ttot, 10)
+        self.assertEqual(fsa.tsub, 2)
+        self.assertEqual(fsb.ttot, 9)
+        self.assertEqual(fsb.tsub, 4)
+        self.assertEqual(fsc.ttot, 7)
+        self.assertEqual(fsc.tsub, 4)
+        self.assertEqual(cfsab.ttot, 9)
+        self.assertEqual(cfsab.tsub, 2)
+        self.assertEqual(cfsbc.ttot, 7)
+        self.assertEqual(cfsbc.tsub, 4)
+        self.assertEqual(cfsca.ttot, 1)
+        self.assertEqual(cfsca.tsub, 1)
+        self.assertEqual(cfsca.ncall, 1)
+        self.assertEqual(cfsca.nactualcall, 0)
+
+    def test_aabccb(self):
+        _timings = {
+            "a_1": 13,
+            "a_2": 11,
+            "b_1": 9,
+            "c_1": 5,
+            "c_2": 3,
+            "b_2": 1
+        }
+        _yappi._set_test_timings(_timings)
+        self._ncall = 1
+
+        def a():
+            if self._ncall == 1:
+                self._ncall += 1
+                a()
+            else:
+                b()
+
+        def b():
+            if self._ncall == 3:
+                return
+            else:
+                c()
+
+        def c():
+            if self._ncall == 2:
+                self._ncall += 1
+                c()
+            else:
+                b()
+
+        stats = utils.run_and_get_func_stats(a)
+        fsa = utils.find_stat_by_name(stats, 'a')
+        fsb = utils.find_stat_by_name(stats, 'b')
+        fsc = utils.find_stat_by_name(stats, 'c')
+        cfsaa = fsa.children[fsa.index]
+        cfsab = fsa.children[fsb]
+        cfsbc = fsb.children[fsc.full_name]
+        cfscc = fsc.children[fsc]
+        cfscb = fsc.children[fsb]
+        self.assertEqual(fsb.ttot, 9)
+        self.assertEqual(fsb.tsub, 5)
+        self.assertEqual(cfsbc.ttot, 5)
+        self.assertEqual(cfsbc.tsub, 2)
+        self.assertEqual(fsa.ttot, 13)
+        self.assertEqual(fsa.tsub, 4)
+        self.assertEqual(cfsab.ttot, 9)
+        self.assertEqual(cfsab.tsub, 4)
+        self.assertEqual(cfsaa.ttot, 11)
+        self.assertEqual(cfsaa.tsub, 2)
+        self.assertEqual(fsc.ttot, 5)
+        self.assertEqual(fsc.tsub, 4)
+
+    def test_abaa(self):
+        _timings = {"a_1": 13, "b_1": 10, "a_2": 9, "a_3": 5}
+        _yappi._set_test_timings(_timings)
+
+        self._ncall = 1
+
+        def a():
+            if self._ncall == 1:
+                b()
+            elif self._ncall == 2:
+                self._ncall += 1
+                a()
+            else:
+                return
+
+        def b():
+            self._ncall += 1
+            a()
+
+        stats = utils.run_and_get_func_stats(a)
+        fsa = utils.find_stat_by_name(stats, 'a')
+        fsb = utils.find_stat_by_name(stats, 'b')
+        cfsaa = fsa.children[fsa]
+        cfsba = fsb.children[fsa]
+        self.assertEqual(fsb.ttot, 10)
+        self.assertEqual(fsb.tsub, 1)
+        self.assertEqual(fsa.ttot, 13)
+        self.assertEqual(fsa.tsub, 12)
+        self.assertEqual(cfsaa.ttot, 5)
+        self.assertEqual(cfsaa.tsub, 5)
+        self.assertEqual(cfsba.ttot, 9)
+        self.assertEqual(cfsba.tsub, 4)
+
+    def test_aabb(self):
+        _timings = {"a_1": 13, "a_2": 10, "b_1": 9, "b_2": 5}
+        _yappi._set_test_timings(_timings)
+
+        self._ncall = 1
+
+        def a():
+            if self._ncall == 1:
+                self._ncall += 1
+                a()
+            elif self._ncall == 2:
+                b()
+            else:
+                return
+
+        def b():
+            if self._ncall == 2:
+                self._ncall += 1
+                b()
+            else:
+                return
+
+        stats = utils.run_and_get_func_stats(a)
+        fsa = utils.find_stat_by_name(stats, 'a')
+        fsb = utils.find_stat_by_name(stats, 'b')
+        cfsaa = fsa.children[fsa]
+        cfsab = fsa.children[fsb]
+        cfsbb = fsb.children[fsb]
+        self.assertEqual(fsa.ttot, 13)
+        self.assertEqual(fsa.tsub, 4)
+        self.assertEqual(fsb.ttot, 9)
+        self.assertEqual(fsb.tsub, 9)
+        self.assertEqual(cfsaa.ttot, 10)
+        self.assertEqual(cfsaa.tsub, 1)
+        self.assertEqual(cfsab.ttot, 9)
+        self.assertEqual(cfsab.tsub, 4)
+        self.assertEqual(cfsbb.ttot, 5)
+        self.assertEqual(cfsbb.tsub, 5)
+
+    def test_abbb(self):
+        _timings = {"a_1": 13, "b_1": 10, "b_2": 6, "b_3": 1}
+        _yappi._set_test_timings(_timings)
+
+        self._ncall = 1
+
+        def a():
+            if self._ncall == 1:
+                b()
+
+        def b():
+            if self._ncall == 3:
+                return
+            self._ncall += 1
+            b()
+
+        stats = utils.run_and_get_func_stats(a)
+        fsa = utils.find_stat_by_name(stats, 'a')
+        fsb = utils.find_stat_by_name(stats, 'b')
+        cfsab = fsa.children[fsb]
+        cfsbb = fsb.children[fsb]
+        self.assertEqual(fsa.ttot, 13)
+        self.assertEqual(fsa.tsub, 3)
+        self.assertEqual(fsb.ttot, 10)
+        self.assertEqual(fsb.tsub, 10)
+        self.assertEqual(fsb.ncall, 3)
+        self.assertEqual(fsb.nactualcall, 1)
+        self.assertEqual(cfsab.ttot, 10)
+        self.assertEqual(cfsab.tsub, 4)
+        self.assertEqual(cfsbb.ttot, 6)
+        self.assertEqual(cfsbb.tsub, 6)
+        self.assertEqual(cfsbb.nactualcall, 0)
+        self.assertEqual(cfsbb.ncall, 2)
+
+    def test_aaab(self):
+        _timings = {"a_1": 13, "a_2": 10, "a_3": 6, "b_1": 1}
+        _yappi._set_test_timings(_timings)
+
+        self._ncall = 1
+
+        def a():
+            if self._ncall == 3:
+                b()
+                return
+            self._ncall += 1
+            a()
+
+        def b():
+            return
+
+        stats = utils.run_and_get_func_stats(a)
+        fsa = utils.find_stat_by_name(stats, 'a')
+        fsb = utils.find_stat_by_name(stats, 'b')
+        cfsaa = fsa.children[fsa]
+        cfsab = fsa.children[fsb]
+        self.assertEqual(fsa.ttot, 13)
+        self.assertEqual(fsa.tsub, 12)
+        self.assertEqual(fsb.ttot, 1)
+        self.assertEqual(fsb.tsub, 1)
+        self.assertEqual(cfsaa.ttot, 10)
+        self.assertEqual(cfsaa.tsub, 9)
+        self.assertEqual(cfsab.ttot, 1)
+        self.assertEqual(cfsab.tsub, 1)
+
+    def test_abab(self):
+        _timings = {"a_1": 13, "b_1": 10, "a_2": 6, "b_2": 1}
+        _yappi._set_test_timings(_timings)
+
+        self._ncall = 1
+
+        def a():
+            b()
+
+        def b():
+            if self._ncall == 2:
+                return
+            self._ncall += 1
+            a()
+
+        stats = utils.run_and_get_func_stats(a)
+        fsa = utils.find_stat_by_name(stats, 'a')
+        fsb = utils.find_stat_by_name(stats, 'b')
+        cfsab = fsa.children[fsb]
+        cfsba = fsb.children[fsa]
+        self.assertEqual(fsa.ttot, 13)
+        self.assertEqual(fsa.tsub, 8)
+        self.assertEqual(fsb.ttot, 10)
+        self.assertEqual(fsb.tsub, 5)
+        self.assertEqual(cfsab.ttot, 10)
+        self.assertEqual(cfsab.tsub, 5)
+        self.assertEqual(cfsab.ncall, 2)
+        self.assertEqual(cfsab.nactualcall, 1)
+        self.assertEqual(cfsba.ttot, 6)
+        self.assertEqual(cfsba.tsub, 5)
+
+
+if __name__ == '__main__':
+    #     import sys;sys.argv = ['', 'BasicUsage.test_run_as_script']
+    #     import sys;sys.argv = ['', 'MultithreadedScenarios.test_subsequent_profile']
+    unittest.main()
--- a/tests/test_hooks.py
+++ b/tests/test_hooks.py
@@ -5,7 +5,7 @@ import unittest
 import time
 
 import yappi
-import utils
+import tests.utils as utils
 
 
 def a():
--- a/tests/test_tags.py
+++ b/tests/test_tags.py
@@ -2,7 +2,7 @@ import unittest
 import yappi
 import threading
 import time
-from utils import YappiUnitTestCase, find_stat_by_name, burn_cpu, burn_io
+from .utils import YappiUnitTestCase, find_stat_by_name, burn_cpu, burn_io
 
 
 class MultiThreadTests(YappiUnitTestCase):