Sync GN unit tests with GYP, add checking script.

tools/gn/bin/compare_test_lists.py

Index: tools/gn/bin/compare_test_lists.py
diff --git a/tools/gn/bin/compare_test_lists.py b/tools/gn/bin/compare_test_lists.py
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index 0000000000000000000000000000000000000000..37fb1bf1e262f2b6e6da567ef87cb6f2cf78fe1e
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+++ b/tools/gn/bin/compare_test_lists.py
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+# Copyright 2015 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.
+
+# This script compares the gtest test list for two different builds.
+#
+# Usage:
+#   compare_test_lists.py <build_dir_1> <build_dir_2> <binary_name>
+#
+# For example, from the "src" directory:
+#   python tools/gn/bin/compare_test_lists.py out/Debug out/gnbuild ipc_tests
+#
+# This will compile the given binary in both output directories, then extracts
+# the test lists and prints missing or extra tests between the first and the
+# second build.
+
+import os
+import subprocess
+import sys
+
+def BuildBinary(build_dir, binary_name):
+  """Builds the given binary in the given directory with Ninja.
+
+  Returns True on success."""
+  return subprocess.call(["ninja", "-C", build_dir, binary_name]) == 0
+
+
+def GetTestList(path_to_binary):
+  """Returns a set of full test names.
+
+  Each test will be of the form "Case.Test". There will be a separate line
+  for each combination of Case/Test (there are often multiple tests in each
+  case).
+
+  Throws an exception on failure."""
+  raw_output = subprocess.check_output([path_to_binary, "--gtest_list_tests"])
+  input_lines = raw_output.split('\n')
+
+  # The format of the gtest_list_tests output is:
+  # "Case1."
+  # "  Test1  # <Optional extra stuff>"
+  # "  Test2"
+  # "Case2."
+  # "  Test1"
+  case_name = ''  # Includes trailing dot.
+  test_set = set()
+  for line in input_lines:
+    if len(line) > 1:
+      if line[0] == ' ':
+        # Indented means a test in previous case.
+        test_set.add(case_name + line[:line.find('#')].strip())
+      else:
+        # New test case.
+        case_name = line.strip()
+
+  return test_set
+
+
+def PrintSetDiff(a_name, a, b_name, b, binary_name):
+  """Prints the test list difference between the given sets a and b.
+
+  a_name and b_name will be used to refer to the directories of the two sets,
+  and the binary name will be shown as the source of the output."""
+
+  a_not_b = list(a - b)
+  if len(a_not_b):
+    print "\n", binary_name, "tests in", a_name, "but not", b_name
+    a_not_b.sort()
+    for cur in a_not_b:
+      print "  ", cur
+
+  b_not_a = list(b - a)
+  if len(b_not_a):
+    print "\n", binary_name, "tests in", b_name, "but not", a_name
+    b_not_a.sort()
+    for cur in b_not_a:
+      print "  ", cur
+
+  if len(a_not_b) == 0 and len(b_not_a) == 0:
+    print "\nTests match!"
+
+
+def Run(a_dir, b_dir, binary_name):
+  if not BuildBinary(a_dir, binary_name):
+    print "Building", binary_name, "in", a_dir, "failed"
+    return 1
+  if not BuildBinary(b_dir, binary_name):
+    print "Building", binary_name, "in", b_dir, "failed"
+    return 1
+
+  a_tests = GetTestList(os.path.join(a_dir, binary_name))
+  b_tests = GetTestList(os.path.join(b_dir, binary_name))
+
+  PrintSetDiff(a_dir, a_tests, b_dir, b_tests, binary_name)
+
+
+if len(sys.argv) != 4:
+  print "Usage: compare_test_lists.py <build_dir_1> <build_dir_2> " \
+      "<test_binary_name>"
+  sys.exit(1)
+sys.exit(Run(sys.argv[1], sys.argv[2], sys.argv[3]))