Revert "Implementation #3 of running other unit tests from scripts_re…

…gression_tests"

This reverts commit b33215c.

I think that implementation #2 is probably the best: calling python -m unittest
discover from within a single unit test in scripts_regression_tests

utils/python/tests/scripts_regression_tests.py

@@ -39,6 +39,23 @@ def do_unit_tests(self, script,from_dir=SCRIPT_DIR):
         stat, output, _ = run_cmd("./%s --test 2>&1" % script, from_dir=from_dir)
         self.assertEqual(stat, 0, msg=output)
 
+    def test_unittests(self):
+        # Finds all files contained in LIB_DIR or its subdirectories that match
+        # the pattern 'test*.py', and runs the unit tests found there (i.e.,
+        # tests defined using python's unittest module).
+        #
+        # This is analogous to running:
+        #     python -m unittest discover
+        #
+        # It seems kind of funny to run a bunch of other unit test suites from
+        # within this single unit test, but doing it this way makes it
+        # consistent with how we run other tests in this module.
+
+        cmd = 'python -m unittest discover'
+        stat, output, _ = run_cmd("%s 2>&1"%cmd, from_dir = LIB_DIR)
+
+        self.assertEqual(stat, 0, msg=output)
+
     def test_cime_bisect_unit_test(self):
         self.do_unit_tests("cime_bisect",from_dir=TOOLS_DIR)
 
@@ -1630,25 +1647,7 @@ def _main_func():
 
     CIME.utils.handle_standard_logging_options(args)
 
-    # Finds all files contained in LIB_DIR or its subdirectories that match the
-    # pattern 'test*.py', and runs the unit tests found there (i.e., tests
-    # defined using python's unittest module).
-    #
-    # This is analogous to running:
-    #     python -m unittest discover
-    testsuite_from_discovery = \
-      unittest.defaultTestLoader.discover(start_dir=LIB_DIR)
-
-    # Add tests defined in this module
-    testsuite_from_this_module = \
-      unittest.defaultTestLoader.loadTestsFromModule(sys.modules[__name__])
-
-    # Run all tests found here and elsewhere
-    suitelist = [testsuite_from_discovery, testsuite_from_this_module]
-    fullsuite = unittest.TestSuite(suitelist)
-    unittest.installHandler()
-    unittest.TextTestRunner(verbosity=2).run(fullsuite)
-
+    unittest.main(verbosity=2, catchbreak=True)
 
 if (__name__ == "__main__"):
     _main_func()