Parsing expectations for run-webkit-tests takes >20 seconds.

Tools/Scripts/webkitpy/layout_tests/models/test_expectations.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 67 matching lines @@
     NEEDS_MANUAL_REBASELINE_MODIFIER = 'needsmanualrebaseline'
     PASS_EXPECTATION = 'pass'
     SKIP_MODIFIER = 'skip'
     SLOW_MODIFIER = 'slow'
     WONTFIX_MODIFIER = 'wontfix'
 
     TIMEOUT_EXPECTATION = 'timeout'
 
     MISSING_BUG_WARNING = 'Test lacks BUG specifier.'
 
-    def __init__(self, port, full_test_list, is_lint_mode):
+    def __init__(self, port, all_tests, is_lint_mode):
         self._port = port
         self._test_configuration_converter = TestConfigurationConverter(set(port.all_test_configurations()), port.configuration_specifier_macros())
-        self._full_test_list = full_test_list
+
+        if all_tests:
+            self._all_tests = set(all_tests)
+        else:
+            self._all_tests = set()
+
         self._is_lint_mode = is_lint_mode
 
     def parse(self, filename, expectations_string):
         expectation_lines = []
         line_number = 0
         for line in expectations_string.split("\n"):
             line_number += 1
             test_expectation = self._tokenize_line(filename, line, line_number)
             self._parse_line(test_expectation)
             expectation_lines.append(test_expectation)
@@ skipping 81 matching lines @@
             # Log a warning here since you hit this case any
             # time you update TestExpectations without syncing
             # the LayoutTests directory
             expectation_line.warnings.append('Path does not exist.')
             return False
         return True
 
     def _collect_matching_tests(self, expectation_line):
         """Convert the test specification to an absolute, normalized
         path and make sure directories end with the OS path separator."""
-        # FIXME: full_test_list can quickly contain a big amount of
-        # elements. We should consider at some point to use a more
-        # efficient structure instead of a list. Maybe a dictionary of
-        # lists to represent the tree of tests, leaves being test
-        # files and nodes being categories.
-
-        if not self._full_test_list:
+        if not self._all_tests:
             expectation_line.matching_tests = [expectation_line.path]
             return
 
         if not expectation_line.is_file:
             # this is a test category, return all the tests of the category.
-            expectation_line.matching_tests = [test for test in self._full_test_list if test.startswith(expectation_line.path)]
+            expectation_line.matching_tests = [test for test in self._all_tests if test.startswith(expectation_line.path)]
             return
 
         # this is a test file, do a quick check if it's in the
         # full test suite.
-        if expectation_line.path in self._full_test_list:
+        if expectation_line.path in self._all_tests:
             expectation_line.matching_tests.append(expectation_line.path)
 
     # FIXME: Update the original specifiers and remove this once the old syntax is gone.
     _configuration_tokens_list = [
         'Mac', 'SnowLeopard', 'Lion', 'Retina', 'MountainLion', 'Mavericks',
         'Win', 'XP', 'Win7',
         'Linux',
         'Android',
         'Release',
         'Debug',
@@ skipping 900 matching lines @@
             # If reconstitute_only_these is an empty list, we want to return original_string.
             # So we need to compare reconstitute_only_these to None, not just check if it's falsey.
             if reconstitute_only_these is None or expectation_line in reconstitute_only_these:
                 return expectation_line.to_string(test_configuration_converter)
             return expectation_line.original_string
 
         def nones_out(expectation_line):
             return expectation_line is not None
 
         return "\n".join(filter(nones_out, map(serialize, expectation_lines)))