diff --git a/poky/bitbake/lib/bb/tests/codeparser.py b/poky/bitbake/lib/bb/tests/codeparser.py
index e30e78c..3fd76a8 100644
--- a/poky/bitbake/lib/bb/tests/codeparser.py
+++ b/poky/bitbake/lib/bb/tests/codeparser.py
@@ -123,6 +123,13 @@
         self.parseExpression("sed -i -e 's:IP{:I${:g' $pc")
         self.assertExecs(set(["sed"]))
 
+    def test_parameter_expansion_modifiers(self):
+        # - and + are also valid modifiers for parameter expansion, but are
+        # valid characters in bitbake variable names, so are not included here
+        for i in ('=', ':-', ':=', '?', ':?', ':+', '#', '%', '##', '%%'):
+            name = "foo%sbar" % i
+            self.parseExpression("${%s}" % name)
+            self.assertNotIn(name, self.references)
 
     def test_until(self):
         self.parseExpression("until false; do echo true; done")
diff --git a/poky/bitbake/lib/bb/tests/data.py b/poky/bitbake/lib/bb/tests/data.py
index db3e201..3c511f2 100644
--- a/poky/bitbake/lib/bb/tests/data.py
+++ b/poky/bitbake/lib/bb/tests/data.py
@@ -394,6 +394,15 @@
         self.d.setVar("OVERRIDES", "foo:bar:some_val")
         self.assertEqual(self.d.getVar("TEST"), " testvalue5")
 
+    # Test an override with _<numeric> in it based on a real world OE issue
+    def test_underscore_override(self):
+        self.d.setVar("TARGET_ARCH", "x86_64")
+        self.d.setVar("PN", "test-${TARGET_ARCH}")
+        self.d.setVar("VERSION", "1")
+        self.d.setVar("VERSION_pn-test-${TARGET_ARCH}", "2")
+        self.d.setVar("OVERRIDES", "pn-${PN}")
+        bb.data.expandKeys(self.d)
+        self.assertEqual(self.d.getVar("VERSION"), "2")
 
 class TestKeyExpansion(unittest.TestCase):
     def setUp(self):
diff --git a/poky/bitbake/lib/bb/tests/fetch.py b/poky/bitbake/lib/bb/tests/fetch.py
index 522d202..429998b 100644
--- a/poky/bitbake/lib/bb/tests/fetch.py
+++ b/poky/bitbake/lib/bb/tests/fetch.py
@@ -942,6 +942,25 @@
         self.assertTrue(os.path.exists(os.path.join(repo_path, '.git/modules/extern/json/config')), msg='Missing submodule config "extern/json"')
         self.assertTrue(os.path.exists(os.path.join(repo_path, '.git/modules/extern/sanitizers/config')), msg='Missing submodule config "extern/sanitizers"')
 
+    def test_git_submodule_update_CLI11(self):
+        """ Prevent regression on update detection not finding missing submodule, or modules without needed commits """
+        url = "gitsm://github.com/CLIUtils/CLI11;protocol=git;rev=cf6a99fa69aaefe477cc52e3ef4a7d2d7fa40714"
+        fetcher = bb.fetch.Fetch([url], self.d)
+        fetcher.download()
+
+        # CLI11 that pulls in a newer nlohmann-json
+        url = "gitsm://github.com/CLIUtils/CLI11;protocol=git;rev=49ac989a9527ee9bb496de9ded7b4872c2e0e5ca"
+        fetcher = bb.fetch.Fetch([url], self.d)
+        fetcher.download()
+        # Previous cwd has been deleted
+        os.chdir(os.path.dirname(self.unpackdir))
+        fetcher.unpack(self.unpackdir)
+
+        repo_path = os.path.join(self.tempdir, 'unpacked', 'git')
+        self.assertTrue(os.path.exists(os.path.join(repo_path, '.git/modules/extern/googletest/config')), msg='Missing submodule config "extern/googletest"')
+        self.assertTrue(os.path.exists(os.path.join(repo_path, '.git/modules/extern/json/config')), msg='Missing submodule config "extern/json"')
+        self.assertTrue(os.path.exists(os.path.join(repo_path, '.git/modules/extern/sanitizers/config')), msg='Missing submodule config "extern/sanitizers"')
+
     def test_git_submodule_aktualizr(self):
         url = "gitsm://github.com/advancedtelematic/aktualizr;branch=master;protocol=git;rev=d00d1a04cc2366d1a5f143b84b9f507f8bd32c44"
         fetcher = bb.fetch.Fetch([url], self.d)
@@ -1338,7 +1357,7 @@
 
     def fetch(self, uri=None):
         if uri is None:
-            uris = self.d.getVar('SRC_URI', True).split()
+            uris = self.d.getVar('SRC_URI').split()
             uri = uris[0]
             d = self.d
         else:
@@ -1397,7 +1416,7 @@
 
         srcrev = self.git('rev-parse HEAD', cwd=self.srcdir).strip()
         self.d.setVar('SRCREV', srcrev)
-        uri = self.d.getVar('SRC_URI', True).split()[0]
+        uri = self.d.getVar('SRC_URI').split()[0]
         uri = '%s;nobranch=1;bare=1' % uri
 
         self.fetch_shallow(uri)
@@ -1576,7 +1595,7 @@
         self.add_empty_file('f')
         self.assertRevCount(7, cwd=self.srcdir)
 
-        uri = self.d.getVar('SRC_URI', True).split()[0]
+        uri = self.d.getVar('SRC_URI').split()[0]
         uri = '%s;branch=master,a_branch;name=master,a_branch' % uri
 
         self.d.setVar('BB_GIT_SHALLOW_DEPTH', '0')
@@ -1602,7 +1621,7 @@
         self.add_empty_file('f')
         self.assertRevCount(7, cwd=self.srcdir)
 
-        uri = self.d.getVar('SRC_URI', True).split()[0]
+        uri = self.d.getVar('SRC_URI').split()[0]
         uri = '%s;branch=master,a_branch;name=master,a_branch' % uri
 
         self.d.setVar('BB_GIT_SHALLOW_DEPTH', '0')
diff --git a/poky/bitbake/lib/bb/tests/persist_data.py b/poky/bitbake/lib/bb/tests/persist_data.py
new file mode 100644
index 0000000..812bcbd
--- /dev/null
+++ b/poky/bitbake/lib/bb/tests/persist_data.py
@@ -0,0 +1,142 @@
+# ex:ts=4:sw=4:sts=4:et
+# -*- tab-width: 4; c-basic-offset: 4; indent-tabs-mode: nil -*-
+#
+# BitBake Test for lib/bb/persist_data/
+#
+# Copyright (C) 2018 Garmin Ltd.
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License version 2 as
+# published by the Free Software Foundation.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License along
+# with this program; if not, write to the Free Software Foundation, Inc.,
+# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+#
+
+import unittest
+import bb.data
+import bb.persist_data
+import tempfile
+import threading
+
+class PersistDataTest(unittest.TestCase):
+    def _create_data(self):
+        return bb.persist_data.persist('TEST_PERSIST_DATA', self.d)
+
+    def setUp(self):
+        self.d = bb.data.init()
+        self.tempdir = tempfile.TemporaryDirectory()
+        self.d['PERSISTENT_DIR'] = self.tempdir.name
+        self.data = self._create_data()
+        self.items = {
+                'A1': '1',
+                'B1': '2',
+                'C2': '3'
+                }
+        self.stress_count = 10000
+        self.thread_count = 5
+
+        for k,v in self.items.items():
+            self.data[k] = v
+
+    def tearDown(self):
+        self.tempdir.cleanup()
+
+    def _iter_helper(self, seen, iterator):
+        with iter(iterator):
+            for v in iterator:
+                self.assertTrue(v in seen)
+                seen.remove(v)
+        self.assertEqual(len(seen), 0, '%s not seen' % seen)
+
+    def test_get(self):
+        for k, v in self.items.items():
+            self.assertEqual(self.data[k], v)
+
+        self.assertIsNone(self.data.get('D'))
+        with self.assertRaises(KeyError):
+            self.data['D']
+
+    def test_set(self):
+        for k, v in self.items.items():
+            self.data[k] += '-foo'
+
+        for k, v in self.items.items():
+            self.assertEqual(self.data[k], v + '-foo')
+
+    def test_delete(self):
+        self.data['D'] = '4'
+        self.assertEqual(self.data['D'], '4')
+        del self.data['D']
+        self.assertIsNone(self.data.get('D'))
+        with self.assertRaises(KeyError):
+            self.data['D']
+
+    def test_contains(self):
+        for k in self.items:
+            self.assertTrue(k in self.data)
+            self.assertTrue(self.data.has_key(k))
+        self.assertFalse('NotFound' in self.data)
+        self.assertFalse(self.data.has_key('NotFound'))
+
+    def test_len(self):
+        self.assertEqual(len(self.data), len(self.items))
+
+    def test_iter(self):
+        self._iter_helper(set(self.items.keys()), self.data)
+
+    def test_itervalues(self):
+        self._iter_helper(set(self.items.values()), self.data.itervalues())
+
+    def test_iteritems(self):
+        self._iter_helper(set(self.items.items()), self.data.iteritems())
+
+    def test_get_by_pattern(self):
+        self._iter_helper({'1', '2'}, self.data.get_by_pattern('_1'))
+
+    def _stress_read(self, data):
+        for i in range(self.stress_count):
+            for k in self.items:
+                data[k]
+
+    def _stress_write(self, data):
+        for i in range(self.stress_count):
+            for k, v in self.items.items():
+                data[k] = v + str(i)
+
+    def _validate_stress(self):
+        for k, v in self.items.items():
+            self.assertEqual(self.data[k], v + str(self.stress_count - 1))
+
+    def test_stress(self):
+        self._stress_read(self.data)
+        self._stress_write(self.data)
+        self._validate_stress()
+
+    def test_stress_threads(self):
+        def read_thread():
+            data = self._create_data()
+            self._stress_read(data)
+
+        def write_thread():
+            data = self._create_data()
+            self._stress_write(data)
+
+        threads = []
+        for i in range(self.thread_count):
+            threads.append(threading.Thread(target=read_thread))
+            threads.append(threading.Thread(target=write_thread))
+
+        for t in threads:
+            t.start()
+        self._stress_read(self.data)
+        for t in threads:
+            t.join()
+        self._validate_stress()
+
diff --git a/poky/bitbake/lib/bb/tests/utils.py b/poky/bitbake/lib/bb/tests/utils.py
index 2f4ccf3..f1cd83a 100644
--- a/poky/bitbake/lib/bb/tests/utils.py
+++ b/poky/bitbake/lib/bb/tests/utils.py
@@ -42,6 +42,10 @@
         self.assertTrue(result < 0)
         result = bb.utils.vercmp_string('1.1', '1.0+1.1-beta1')
         self.assertTrue(result > 0)
+        result = bb.utils.vercmp_string('1.', '1.1')
+        self.assertTrue(result < 0)
+        result = bb.utils.vercmp_string('1.1', '1.')
+        self.assertTrue(result > 0)
 
     def test_explode_dep_versions(self):
         correctresult = {"foo" : ["= 1.10"]}