test_run.py: allow specifying of individual tests

If the user specifies any tests on the command line then only run
those.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>

test_run.py

@@ -48,12 +48,20 @@ def retrieve_test_list(config_file=f"{PARENT_DIR}/.buildkite/test_description.js
     parser.add_argument("-l", "--list-tests",
                         action='store_true', default=False,
                         help="List available tests")
+    parser.add_argument('tests', nargs='*',
+                        help="The tests to run. If none are specified "
+                        "run all the available tests.")
     args = parser.parse_args()
 
     test_config = retrieve_test_list()
 
     for test in test_config["tests"]:
         name = test["test_name"]
+
+        if len(args.tests) > 0:
+            if name not in args.tests:
+                continue
+
         command = test["command"]
         command = command.replace("{target_platform}", platform.machine())
         if args.list_tests:
@@ -63,4 +71,5 @@ def retrieve_test_list(config_file=f"{PARENT_DIR}/.buildkite/test_description.js
             setattr(TestsContainer, f"test_{name}", test_func)
 
     if not args.list_tests:
-        unittest.main(verbosity=2)
+        tests_suite = unittest.TestLoader().loadTestsFromTestCase(TestsContainer)
+        unittest.TextTestRunner(verbosity=2).run(tests_suite)