Add UT cases for exprtk functions related to nan

Add unit test cases for below exprtk functions:
* maxIgnoreNaN
* sumIgnoreNaN
* ifNan

Signed-off-by: Lei YU <yulei.sh@bytedance.com>
Change-Id: I4a9ea4b1f88ad1fd76295f88778a5bfc6b4defd1
diff --git a/test/meson.build b/test/meson.build
new file mode 100644
index 0000000..5454812
--- /dev/null
+++ b/test/meson.build
@@ -0,0 +1,18 @@
+gtest = dependency('gtest', main: true, disabler: true, required: build_tests)
+gmock = dependency('gmock', disabler: true, required: build_tests)
+test_inc = include_directories('.')
+src_inc = include_directories('..')
+
+common_dep = [
+  gtest,
+  gmock,
+]
+
+test_exprtk_tools = executable(
+  'test_exprtk_tools',
+  'test_exprtk_tools.cpp',
+  include_directories: [test_inc, src_inc],
+  dependencies: [common_dep, exprtk]
+)
+
+test('test_exprtk_tools', test_exprtk_tools)