Add option to only clone and immediately exit the test runner.

test.py

@@ -357,7 +357,7 @@ class _VimTest(unittest.TestCase):
             _VimTest.version, _ = subprocess.Popen(["vim", "--version"],
                     stdout=subprocess.PIPE, stderr=subprocess.PIPE).communicate()
             if PYTHON3:
-                _VimTest.version = stdout.decode("utf-8")
+                _VimTest.version = _VimTest.version.decode("utf-8")
 
         if self.plugins and not self.test_plugins:
             return self.skipTest("Not testing integration with other plugins.")
@@ -3363,6 +3363,8 @@ if __name__ == '__main__':
 
         p.add_option("-v", "--verbose", dest="verbose", action="store_true",
             help="print name of tests as they are executed")
+        p.add_option("--clone-plugins", action="store_true",
+            help="Only clones dependant plugins and exits the test runner.")
         p.add_option("--plugins", action="store_true",
             help="Run integration tests with other Vim plugins.")
         p.add_option("--interface", type=str,
@@ -3386,11 +3388,14 @@ if __name__ == '__main__':
 
         return o, args
 
+    def main():
         options,selected_tests = parse_args()
 
         test_loader = unittest.TestLoader()
         all_test_suites = test_loader.loadTestsFromModule(__import__("test"))
 
+        vim = None
+        if not options.clone_plugins:
             if platform.system() == "Windows":
                 raise RuntimeError("TODO: TestSuite is broken under windows. Volunteers wanted!.")
                 # vim = VimInterfaceWindows()
@@ -3401,15 +3406,14 @@ if __name__ == '__main__':
                 elif options.interface == "tmux":
                     vim = VimInterfaceTmux(options.session)
 
-    # Inform all test case which screen session to use
         suite = unittest.TestSuite()
         all_other_plugins = set()
         for s in all_test_suites:
             for test in s:
-            test.vim = vim
                 test.interrupt = options.interrupt
                 test.retries = options.retries
                 test.test_plugins = options.plugins
+                test.vim = vim
                 all_other_plugins.update(test.plugins)
 
                 if len(selected_tests):
@@ -3418,8 +3422,10 @@ if __name__ == '__main__':
                         continue
                 suite.addTest(test)
 
-    if options.plugins:
+        if options.plugins or options.clone_plugins:
             setup_other_plugins(all_other_plugins)
+            if options.clone_plugins:
+                return
 
         if options.verbose:
             v = 2
@@ -3427,4 +3433,6 @@ if __name__ == '__main__':
             v = 1
         res = unittest.TextTestRunner(verbosity=v).run(suite)
 
+    main()
+
 # vim:fileencoding=utf-8:foldmarker={{{#,#}}}: