Allow running against a single file

ansible_testing/modules.py

@@ -293,7 +293,7 @@ class PythonPackageValidator(Validator):
 
 def main():
     parser = argparse.ArgumentParser()
-    parser.add_argument('modules', help='Path to modules')
+    parser.add_argument('modules', help='Path to module or module directory')
     parser.add_argument('-w', '--warnings', help='Show warnings',
                         action='store_true')
     args = parser.parse_args()
@@ -302,6 +302,13 @@ def main():
 
     exit = []
 
+    # Allow testing against a single file
+    if os.path.isfile(args.modules):
+        mv = ModuleValidator(os.path.abspath(args.modules))
+        mv.validate()
+        exit.append(mv.report(args.warnings))
+        sys.exit(sum(exit))
+
     for root, dirs, files in os.walk(args.modules):
         basedir = root[len(args.modules)+1:].split('/', 1)[0]
         if basedir in BLACKLIST_DIRS: