test-bots: Add support for testing a single bot.

contrib_bots/test-bots

@@ -3,16 +3,26 @@
 from __future__ import absolute_import
 from __future__ import print_function
 
+import argparse
 import os
 import sys
 import unittest
 from unittest import TestCase
 
-if __name__ == '__main__':
+def dir_join(dir1, dir2):
+    # type: (str, str) -> str
+    return os.path.abspath(os.path.join(dir1, dir2))
 
-    def dir_join(dir1, dir2):
-        # type: (str, str) -> str
-        return os.path.abspath(os.path.join(dir1, dir2))
+
+if __name__ == '__main__':
+    description = 'Script to run test_<bot>.py files in bots/<bot> directories'
+    parser = argparse.ArgumentParser(description=description)
+    parser.add_argument('--bot',
+                        nargs=1,
+                        type=str,
+                        action='store',
+                        help='test specified single bot')
+    args = parser.parse_args()
 
     bots_dir = os.path.dirname(os.path.abspath(__file__))
     root_dir = dir_join(bots_dir, '..')
@@ -23,6 +33,8 @@ if __name__ == '__main__':
     # mypy doesn't recognize the TestLoader attribute, even though the code
     # is executable
     loader = unittest.TestLoader() # type: ignore
+    if args.bot is not None:
+        bots_test_dir = dir_join(bots_test_dir, args.bot[0])
     suite = loader.discover(start_dir=bots_test_dir, top_level_dir=root_dir)
     runner = unittest.TextTestRunner(verbosity=2)
     # same issue as for TestLoader