diff --git a/tuf/tests/aggregate_tests.py b/tuf/tests/aggregate_tests.py
index cf65a398..39fe8457 100755
--- a/tuf/tests/aggregate_tests.py
+++ b/tuf/tests/aggregate_tests.py
@@ -4,6 +4,7 @@
 
 <Author>
   Konstantin Andrianov
+  Zane Fisher
 
 <Started>
   January 26, 2013
@@ -12,15 +13,21 @@
   See LICENSE for licensing information.
 
 <Purpose>
-  Run all the unit tests in 'tuf/tests'.
+  Run all the unit tests from every .py file beginning with "test_" in 'tuf/tests'.
 
 """
 
+import unittest
 import glob
+import tuf.keydb as keydb
+import tuf.repo.keystore as keystore
+import tuf.roledb as roledb
 
 tests_list = glob.glob('test_*.py')
-for test in tests_list:
-  __import__(test[:-3])
 
-import system_tests.test_util_test_tools
-import system_tests.test_replay_attack
+# Remove '.py' from each filename.
+tests_list = [test[:-3] for test in tests_list]
+
+suite = unittest.TestLoader().loadTestsFromNames(tests_list)
+
+unittest.TextTestRunner(verbosity=2).run(suite)
diff --git a/tuf/tests/test_download.py b/tuf/tests/test_download.py
index 44b3c732..96716875 100755
--- a/tuf/tests/test_download.py
+++ b/tuf/tests/test_download.py
@@ -186,5 +186,5 @@ def test_download_url_to_tempfileobj(self):
 
 
 # Run unit test.
-suite = unittest.TestLoader().loadTestsFromTestCase(TestDownload)
-unittest.TextTestRunner(verbosity=2).run(suite)
+if __name__ == '__main__':
+  unittest.main()
diff --git a/tuf/tests/test_formats.py b/tuf/tests/test_formats.py
index 2e41e2f6..14b5281d 100755
--- a/tuf/tests/test_formats.py
+++ b/tuf/tests/test_formats.py
@@ -628,5 +628,5 @@ def test_encode_canonical(self):
 
 
 # Run unit test.
-suite = unittest.TestLoader().loadTestsFromTestCase(TestFormats)
-unittest.TextTestRunner(verbosity=2).run(suite)
+if __name__ == '__main__':
+  unittest.main()
diff --git a/tuf/tests/test_hash.py b/tuf/tests/test_hash.py
index 38537ec7..0a56c175 100755
--- a/tuf/tests/test_hash.py
+++ b/tuf/tests/test_hash.py
@@ -225,5 +225,5 @@ def _do_update_file_obj(self, library):
 
 
 # Run unit test.
-suite = unittest.TestLoader().loadTestsFromTestCase(TestHash)
-unittest.TextTestRunner(verbosity=3).run(suite)
+if __name__ == '__main__':
+  unittest.main()
diff --git a/tuf/tests/test_keydb.py b/tuf/tests/test_keydb.py
index fe61a976..5dedc411 100755
--- a/tuf/tests/test_keydb.py
+++ b/tuf/tests/test_keydb.py
@@ -217,5 +217,5 @@ def test_create_keydb_from_root_metadata(self):
 
 
 # Run unit test.
-suite = unittest.TestLoader().loadTestsFromTestCase(TestKeydb)
-unittest.TextTestRunner(verbosity=2).run(suite)
+if __name__ == '__main__':
+  unittest.main()
diff --git a/tuf/tests/test_keystore.py b/tuf/tests/test_keystore.py
index a78acbb6..196bb7d4 100755
--- a/tuf/tests/test_keystore.py
+++ b/tuf/tests/test_keystore.py
@@ -321,5 +321,5 @@ def test_internal_decrypt(self):
 
 
 # Run the unit tests.
-suite = unittest.TestLoader().loadTestsFromTestCase(TestKeystore)
-unittest.TextTestRunner(verbosity=2).run(suite)
+if __name__ == '__main__':
+  unittest.main()
diff --git a/tuf/tests/test_mirrors.py b/tuf/tests/test_mirrors.py
index 2c2e0e9d..4afca814 100755
--- a/tuf/tests/test_mirrors.py
+++ b/tuf/tests/test_mirrors.py
@@ -97,5 +97,5 @@ def test_get_list_of_mirrors(self):
 
 
 # Run the unittests
-suite = unittest.TestLoader().loadTestsFromTestCase(TestMirrors)
-unittest.TextTestRunner(verbosity=2).run(suite)
+if __name__ == '__main__':
+  unittest.main()
diff --git a/tuf/tests/test_push.py b/tuf/tests/test_push.py
index 4de06b1e..699881c0 100644
--- a/tuf/tests/test_push.py
+++ b/tuf/tests/test_push.py
@@ -165,5 +165,5 @@ def test_expected_behaviour_of_push_with_scp(self):
 
 
 # Run the unittests
-suite = unittest.TestLoader().loadTestsFromTestCase(TestPush)
-unittest.TextTestRunner(verbosity=2).run(suite)
+if __name__ == '__main__':
+  unittest.main()
diff --git a/tuf/tests/test_pushtoolslib.py b/tuf/tests/test_pushtoolslib.py
index a1938cd6..60c4975f 100644
--- a/tuf/tests/test_pushtoolslib.py
+++ b/tuf/tests/test_pushtoolslib.py
@@ -165,5 +165,5 @@ def test_exceptions_handeling_of_read_config_file(self):
 
 
 # Run the unittests
-suite = unittest.TestLoader().loadTestsFromTestCase(TestPushtoolslib)
-unittest.TextTestRunner(verbosity=2).run(suite)
\ No newline at end of file
+if __name__ == '__main__':
+  unittest.main()
diff --git a/tuf/tests/test_quickstart.py b/tuf/tests/test_quickstart.py
index 831941d6..771f397e 100755
--- a/tuf/tests/test_quickstart.py
+++ b/tuf/tests/test_quickstart.py
@@ -191,5 +191,5 @@ def _remove_repository_directories(repo_dir, keystore_dir, client_dir):
 
 
 # Run the unit tests.
-suite = unittest.TestLoader().loadTestsFromTestCase(TestQuickstart)
-unittest.TextTestRunner(verbosity=2).run(suite)
+if __name__ == '__main__':
+  unittest.main()
diff --git a/tuf/tests/test_roledb.py b/tuf/tests/test_roledb.py
index 63a34198..1154dc57 100755
--- a/tuf/tests/test_roledb.py
+++ b/tuf/tests/test_roledb.py
@@ -65,6 +65,7 @@ def test_clear_roledb(self):
 
   def test_add_role(self):
     # Test conditions where the arguments are valid.
+    print('ROLES: '+str(tuf.roledb._roledb_dict.keys()))
     self.assertEqual(0, len(tuf.roledb._roledb_dict)) 
     rolename = 'targets'
     roleinfo = {'keyids': ['123'], 'threshold': 1}
@@ -396,5 +397,5 @@ def _test_rolename(self, test_function):
 
 
 # Run the unit tests.
-suite = unittest.TestLoader().loadTestsFromTestCase(TestRoledb)
-unittest.TextTestRunner(verbosity=2).run(suite)
+if __name__ == '__main__':
+  unittest.main()
diff --git a/tuf/tests/test_rsa_key.py b/tuf/tests/test_rsa_key.py
index e63cca7d..d6543378 100755
--- a/tuf/tests/test_rsa_key.py
+++ b/tuf/tests/test_rsa_key.py
@@ -180,5 +180,5 @@ def test_verify_signature(self):
 
 
 # Run the unit tests.
-suite = unittest.TestLoader().loadTestsFromTestCase(TestRsa_key)
-unittest.TextTestRunner(verbosity=2).run(suite)
+if __name__ == '__main__':
+  unittest.main()
diff --git a/tuf/tests/test_schema.py b/tuf/tests/test_schema.py
index d263fe03..f72ae02b 100755
--- a/tuf/tests/test_schema.py
+++ b/tuf/tests/test_schema.py
@@ -326,5 +326,5 @@ def test_RegularExpression(self):
 
 
 # Run the unit tests.
-suite = unittest.TestLoader().loadTestsFromTestCase(TestSchema)
-unittest.TextTestRunner(verbosity=2).run(suite)
+if __name__ == '__main__':
+  unittest.main()
diff --git a/tuf/tests/test_sig.py b/tuf/tests/test_sig.py
index f60acfa3..dd302748 100755
--- a/tuf/tests/test_sig.py
+++ b/tuf/tests/test_sig.py
@@ -391,5 +391,5 @@ def test_signable_has_invalid_format(self):
 
 
 # Run unit test.
-suite = unittest.TestLoader().loadTestsFromTestCase(TestSig)
-unittest.TextTestRunner(verbosity=2).run(suite)
+if __name__ == '__main__':
+  unittest.main()
diff --git a/tuf/tests/test_signercli.py b/tuf/tests/test_signercli.py
index 97a56f25..ccf07741 100755
--- a/tuf/tests/test_signercli.py
+++ b/tuf/tests/test_signercli.py
@@ -1484,9 +1484,12 @@ def _mock_get_keyids(junk):
 
 
 # Run unit tests.
-loader = unittest_toolbox.unittest.TestLoader
-suite = loader().loadTestsFromTestCase(TestSignercli)
-try:
-  unittest_toolbox.unittest.TextTestRunner(verbosity=2).run(suite)
-finally:
-  unittest_toolbox.Modified_TestCase.clear_toolbox()
+#loader = unittest_toolbox.unittest.TestLoader
+#suite = loader().loadTestsFromTestCase(TestSignercli)
+#try:
+#  unittest_toolbox.unittest.TextTestRunner(verbosity=2).run(suite)
+#finally:
+#  unittest_toolbox.Modified_TestCase.clear_toolbox()
+
+if __name__ == '__main__':
+  unittest.main()
diff --git a/tuf/tests/test_signerlib.py b/tuf/tests/test_signerlib.py
index efdf208b..cdda3bbe 100755
--- a/tuf/tests/test_signerlib.py
+++ b/tuf/tests/test_signerlib.py
@@ -898,9 +898,12 @@ def _get_signed_role_info(self, role, directory=None):
 
 
 # Run unit test.
-suite = unittest.TestLoader().loadTestsFromTestCase(TestSignerlib)
-try:
-  unittest.TextTestRunner(verbosity=2).run(suite) 
-finally:
-  unit_tbox.clear_toolbox()
-  tuf.repo.keystore.clear_keystore()
+#suite = unittest.TestLoader().loadTestsFromTestCase(TestSignerlib)
+#try:
+#  unittest.TextTestRunner(verbosity=2).run(suite) 
+#finally:
+#  unit_tbox.clear_toolbox()
+#  tuf.repo.keystore.clear_keystore()
+
+if __name__ == '__main__':
+  unittest.main()
diff --git a/tuf/tests/test_updater.py b/tuf/tests/test_updater.py
index 75c7dc77..74a1d19a 100755
--- a/tuf/tests/test_updater.py
+++ b/tuf/tests/test_updater.py
@@ -408,7 +408,7 @@ def test_2__import_delegations(self):
 
     #  Verify that there was no change in roledb and keydb dictionaries
     #  by checking the number of elements in the dictionaries.
-    self.assertEqual(len(roledb._roledb_dict), 5)
+    self.assertEqual(len(roledb._roledb_dict), 5)       
     self.assertEqual(len(keydb._keydb_dict), 5)
 
     # Test: normal case, first level delegation.
@@ -1142,18 +1142,22 @@ def test_8_remove_obsolete_targets(self):
 
 
 # Run all unit tests.
-loader = unittest_toolbox.unittest.TestLoader()
-suite = unittest_toolbox.unittest.TestSuite()
+#loader = unittest_toolbox.unittest.TestLoader()
+#suite = unittest_toolbox.unittest.TestSuite()
 
-class1_tests = loader.loadTestsFromTestCase(TestUpdater_init_)
-class2_tests = loader.loadTestsFromTestCase(TestUpdater)
+#class1_tests = loader.loadTestsFromTestCase(TestUpdater_init_)
+#class2_tests = loader.loadTestsFromTestCase(TestUpdater)
  
-suite.addTest(class1_tests)
-suite.addTest(class2_tests)
+#suite.addTest(class1_tests)
+#suite.addTest(class2_tests)
 
-try:
-  unittest_toolbox.unittest.TextTestRunner(verbosity=2).run(suite)
-finally:
-  #  Removing repositories.
-  setup.remove_all_repositories(TestUpdater.repositories['main_repository'])
-  unittest_toolbox.Modified_TestCase.clear_toolbox()
+#try:
+#  unittest_toolbox.unittest.TextTestRunner(verbosity=2).run(suite)
+#finally:
+#  #  Removing repositories.
+#  setup.remove_all_repositories(TestUpdater.repositories['main_repository'])
+#  unittest_toolbox.Modified_TestCase.clear_toolbox()
+
+
+if __name__ == '__main__':
+  unittest.main()
diff --git a/tuf/tests/test_util.py b/tuf/tests/test_util.py
index ec0ccfb2..9636d606 100755
--- a/tuf/tests/test_util.py
+++ b/tuf/tests/test_util.py
@@ -302,5 +302,5 @@ def  test_B6_load_json_file(self):
 
 
 # Run unit test.
-suite = unittest.TestLoader().loadTestsFromTestCase(TestUtil)
-unittest.TextTestRunner(verbosity=2).run(suite)
+if __name__ == '__main__':
+  unittest.main()