hard code list for python3

scripts/tests/list_tests

@@ -1,26 +1,58 @@
 #!/usr/bin/env python
-
+# This script will print the list of test classes in
+# scripts_regression_tests.py, however discover doesnt seem to work
+# correctly in python3 so the list is hard coded.
+# When run in python2 the hard coded list is checked for correctness.
+#
 import unittest
+import sys
 DEBUG = False
 
 #pylint: disable=protected-access
 def list_tests_from():
-    loader = unittest.TestLoader()
-    suite = loader.discover(".", pattern="scripts_regression_tests.py")
-    test_classes = []
-    for alltests in suite:
-        tests = alltests._tests
-        if len(tests):
-            for atest in tests:
-                if DEBUG:
-                    print(atest)
-                for btest in atest._tests:
-                    btestname = btest.__str__().split()
-                    test_classes.append(btestname[1][1:-1].split('.')[1])
-            # add this explicitly, not captured by the above
-            test_classes.append("B_CheckCode")
-            for ctest in sorted(list(set(test_classes))):
-                print(ctest)
+    test_classes_hard = hard_coded_list()
+    if sys.hexversion < 0x03000000:
+        loader = unittest.TestLoader()
+        suite = loader.discover(".", pattern="scripts_regression_tests.py")
+        test_classes = []
+        for alltests in suite:
+            tests = alltests._tests
+            if len(tests):
+                for atest in tests:
+                    if DEBUG:
+                        print(atest)
+                    for btest in atest._tests:
+                        btestname = btest.__str__().split()
+                        test_classes.append(btestname[1][1:-1].split('.')[1])
+        # add this explicitly, not captured by the above
+        test_classes.append("B_CheckCode")
+        if set(test_classes) != set(test_classes_hard):
+            print ("Error: hard coded test_class list out of sync with actual, please fix")
+        test_classes_hard = test_classes
+
+    for ctest in sorted(list(set(test_classes_hard))):
+        print(ctest)
+
+def hard_coded_list():
+    return ('A_RunUnitTests',
+            'B_CheckCode',
+            'G_TestMacrosBasic',
+            'H_TestMakeMacros',
+            'I_TestCMakeMacros',
+            'J_TestCreateNewcase',
+            'K_TestCimeCase',
+            'L_TestSaveTimings',
+            'M_TestWaitForTests',
+            'N_TestUnitTest',
+            'O_TestTestScheduler',
+            'P_TestJenkinsGenericJob',
+            'Q_TestBlessTestResults',
+            'S_TestManageAndQuery',
+            'T_TestRunRestart',
+            'X_TestSingleSubmit',
+            'Z_FullSystemTest')
+
+
 
 if __name__ == "__main__":
     # Include the directories