--- a/testing/firefox-ui/mach_commands.py
+++ b/testing/firefox-ui/mach_commands.py
@@ -27,17 +27,17 @@ def setup_argument_parser_update():
     from firefox_ui_harness.arguments.update import UpdateArguments
     return UpdateArguments()
 
 
 def run_firefox_ui_test(testtype=None, topsrcdir=None, **kwargs):
     from mozlog.structured import commandline
     import firefox_ui_harness
 
-    parser = setup_argument_parser_functional()
+    parser = setup_argument_parser_update()
 
     test_types = {
         'functional': {
             'default_tests': [
                 os.path.join('puppeteer', 'manifest.ini'),
                 os.path.join('functional', 'manifest.ini'),
             ],
             'cli_module': firefox_ui_harness.cli_functional,
@@ -54,17 +54,17 @@ def run_firefox_ui_test(testtype=None, t
 
     # Set the resources path which is used to serve test data via wptserve
     if not kwargs['server_root']:
         kwargs['server_root'] = os.path.join(fxui_dir, 'resources')
 
     # If no tests have been selected, set default ones
     if kwargs.get('tests'):
         tests = kwargs.get('tests')
-    elif not kwargs.get('tests'):
+    else:
         tests = [os.path.join(fxui_dir, 'tests', test)
                            for test in test_types[testtype]['default_tests']]
 
     kwargs['logger'] = commandline.setup_logging('Firefox UI - {} Tests'.format(testtype),
                                                  {"mach": sys.stdout})
 
     args = parser.parse_args(args=tests)