Copy expect_tests from build

expect_tests/util.py

Index: expect_tests/util.py
diff --git a/expect_tests/util.py b/expect_tests/util.py
new file mode 100644
index 0000000000000000000000000000000000000000..fd89b4adf6e1a5785fa2b58fccac7ec2353ca14d
--- /dev/null
+++ b/expect_tests/util.py
@@ -0,0 +1,24 @@
+# Copyright 2014 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+import inspect
+
+EXPECT_TESTS_COVER_FUNCTION = 'EXPECT_TESTS_COVER_FUNCTION'
+
+def covers(coverage_path_function):
+  """Allows annotation of a Test generator function with a function that will
+  return a list of coverage patterns which should be enabled during the use of
+  the Test generator function.
+  """
+  def _decorator(func):
+    setattr(func, EXPECT_TESTS_COVER_FUNCTION, coverage_path_function)
+    return func
+  return _decorator
+
+
+def get_cover_list(test_gen_function):
+  """Given a Test generator, return the list of coverage globs that should
+  be included while executing the Test generator."""
+  return getattr(test_gen_function, EXPECT_TESTS_COVER_FUNCTION,
+                 lambda: [inspect.getabsfile(test_gen_function)])()