Regenerate MANIFEST.json when WPT tests are run

third_party/WebKit/Tools/Scripts/webkitpy/layout_tests/port/base_unittest.py

 # Copyright (C) 2010 Google Inc. All rights reserved.
 #
 # Redistribution and use in source and binary forms, with or without
 # modification, are permitted provided that the following conditions are
 # met:
 #
 #    * Redistributions of source code must retain the above copyright
 # notice, this list of conditions and the following disclaimer.
 #    * Redistributions in binary form must reproduce the above
 # copyright notice, this list of conditions and the following disclaimer
@@ skipping 279 matching lines @@
         self.assertIn('external/wpt/dom/ranges/Range-attributes.html', port.tests([]))
         self.assertNotIn('external/wpt/console/console-is-a-namespace.any.js', port.tests([]))
         self.assertEqual(port.tests(['external']), ['external/wpt/dom/ranges/Range-attributes.html'])
         self.assertEqual(port.tests(['external/']), ['external/wpt/dom/ranges/Range-attributes.html'])
         self.assertEqual(port.tests(['external/csswg-test']), [])
         self.assertEqual(port.tests(['external/wpt']), ['external/wpt/dom/ranges/Range-attributes.html'])
         self.assertEqual(port.tests(['external/wpt/']), ['external/wpt/dom/ranges/Range-attributes.html'])
         self.assertEqual(port.tests(['external/wpt/dom/ranges/Range-attributes.html']),
                          ['external/wpt/dom/ranges/Range-attributes.html'])
 
+        # Assert manifest was regenerated only once (testing memoization).
+        self.assertEqual(port.host.executive.calls, [
+            ['/mock-checkout/third_party/WebKit/Tools/Scripts/webkitpy/thirdparty/wpt/wpt/manifest',
+             '--work', '--tests-root', '/mock-checkout/third_party/WebKit/LayoutTests/external/wpt']
+        ])
+
     def test_is_test_file(self):
         port = self.make_port(with_tests=True)
         is_test_file = functools.partial(Port.is_test_file, port, port.host.filesystem)
         self.assertTrue(is_test_file('', 'foo.html'))
         self.assertTrue(is_test_file('', 'foo.svg'))
         self.assertTrue(is_test_file('', 'test-ref-test.html'))
         self.assertTrue(is_test_file('inspector-unit', 'trie.js'))
         self.assertFalse(is_test_file('inspector-unit', 'foo.html'))
         self.assertFalse(is_test_file('inspector', 'devtools.js'))
         self.assertFalse(is_test_file('', 'foo.png'))
@@ skipping 333 matching lines @@
         self.assertEqual(suite.args, ['--args'])
         self.assertEqual(suite.reference_args, [])
 
     def test_non_default_reference_args(self):
         suite = VirtualTestSuite(prefix='suite', base='base/foo', args=['--args'], references_use_default_args=False)
         self.assertEqual(suite.args, ['--args'])
         self.assertEqual(suite.reference_args, suite.args)
 
     def test_no_slash(self):
         self.assertRaises(AssertionError, VirtualTestSuite, prefix='suite/bar', base='base/foo', args=['--args'])