move tests to separate dir

create macro "pip_test()" for easily add new tests

tests/CMakeLists.txt

@@ -0,0 +1,15 @@
+include(DownloadGTest)
+
+macro(pip_test NAME LIBS)
+	gather_src("${NAME}" CPP_${NAME}_TEST _T_H _T_PH)
+	set(_target pip_${NAME}_test)
+	add_executable(${_target} ${CPP_${NAME}_TEST})
+	target_link_libraries(${_target} pip ${LIBS} gtest_main gmock_main)
+	add_test(NAME ${_target} COMMAND tests)
+	add_custom_target(${_target}_perform ALL COMMAND ${_target})
+	list(APPEND PIP_TESTS_LIST "${NAME}")
+	set(PIP_TESTS_LIST ${PIP_TESTS_LIST} PARENT_SCOPE)
+endmacro()
+
+# Concurrent tests
+pip_test(concurrent "")