adds invoke_tests for conditional pytest or unittest usage; makes tes…

…t class sub-class of TestWrapper; uses setupClass to set script_module/file

mezcla/tests/test_os_utils.py

@@ -20,19 +20,28 @@
 # Local packages
 from mezcla import debug
 from mezcla import os_utils
+from mezcla.unittest_wrapper import TestWrapper, invoke_tests
 
 # Note: Two references are used for the module to be tested:
-#    THE_MODULE:	    global module object
-## TODO: import mezcla.os_utils as THE_MODULE
+#    THE_MODULE:	         global module object
+#    TestWrapper.script_module:  path to file
+THE_MODULE = os_utils
 
-class TestOsUtils:
+class TestOsUtils(TestWrapper):
     """Class for testcase definition"""
 
+    @classmethod
+    def setupClass(cls):
+        """Per-class initialization"""  # why not docstring inherited (or pylint bug?)
+        debug.trace(5, f"TestOsUtils.setupClass({cls})")
+        debug.trace_expr(5, __file__, THE_MODULE)
+        super().setUpClass(filename=__file__, module=THE_MODULE)
+
     def test_split_extension(self):
         """Ensure test_split_extension works as expected"""
         assert(os_utils.split_extension("fubar.txt") == ("fubar", ".txt"))
 
 
 if __name__ == '__main__':
     debug.trace_current_context()
-    pytest.main([__file__])
+    invoke_tests([__file__])