Implement clang tool that converts std::string("") to std::string().

tools/clang/scripts/test_tool.py

Index: tools/clang/scripts/test_tool.py
diff --git a/tools/clang/scripts/test_tool.py b/tools/clang/scripts/test_tool.py
new file mode 100755
index 0000000000000000000000000000000000000000..d2b87a0e10eed72ec92cc58542db1007525cb83b
--- /dev/null
+++ b/tools/clang/scripts/test_tool.py
@@ -0,0 +1,114 @@
+#!/usr/bin/env python
+# Copyright (c) 2013 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.
+
+"""Test harness for chromium clang tools."""
+
+import difflib
+import glob
+import json
+import os
+import os.path
+import subprocess
+import shutil
+import sys
+
+
+def _GenerateCompileCommands(files):
+  """Returns a JSON string containing a compilation database for the input."""
+  return json.dumps([{'directory': '.',
+                      'command': 'clang++ -fsyntax-only -c %s' % f,
+                      'file': f} for f in files], indent=2)
+
+
+def _NumberOfTestsToString(tests):
+  """Returns an English describing the number of tests."""
+  return "%d test%s" % (tests, 's' if tests != 1 else '')
+
+
+def main(argv):
+  if len(argv) < 1:
+    print 'Usage: test_tool.py <clang tool>'
+    print '  <clang tool> is the clang tool to be tested.'
+    sys.exit(1)
+
+  tool_to_test = argv[0]
+  tools_clang_scripts_directory = os.path.dirname(os.path.realpath(__file__))
+  tools_clang_directory = os.path.dirname(tools_clang_scripts_directory)
+  test_directory_for_tool = os.path.join(
+      tools_clang_directory, tool_to_test, 'tests')
+  compile_database = os.path.join(test_directory_for_tool,
+                                  'compile_commands.json')
+  source_files = glob.glob(os.path.join(test_directory_for_tool,
+                                        '*-original.cc'))
+  actual_files = ['-'.join([source_file.rsplit('-', 2)[0], 'actual.cc'])
+                  for source_file in source_files]
+  expected_files = ['-'.join([source_file.rsplit('-', 2)[0], 'expected.cc'])
+                    for source_file in source_files]
+
+  try:
+    # Set up the test environment.
+    for source, actual in zip(source_files, actual_files):
+      shutil.copyfile(source, actual)
+    # Stage the test files in the git index. If they aren't staged, then
+    # run_tools.py will skip them when applying replacements.
+    args = ['git', 'add']
+    args.extend(actual_files)
+    subprocess.check_call(args)
+    # Generate a temporary compilation database to run the tool over.
+    with open(compile_database, 'w') as f:
+      f.write(_GenerateCompileCommands(actual_files))
+
+    args = ['python',
+            os.path.join(tools_clang_scripts_directory, 'run_tool.py'),
+            tool_to_test,
+            test_directory_for_tool]
+    args.extend(actual_files)
+    run_tool = subprocess.Popen(args, stdout=subprocess.PIPE)
+    stdout, _ = run_tool.communicate()
+    if run_tool.returncode != 0:
+      print 'run_tool failed:\n%s' % stdout
+      sys.exit(1)
+
+    passed = 0
+    failed = 0
+    for expected, actual in zip(expected_files, actual_files):
+      print '[ RUN      ] %s' % os.path.relpath(actual)
+      expected_output = actual_output = None
+      with open(expected, 'r') as f:
+        expected_output = f.readlines()
+      with open(actual, 'r') as f:
+        actual_output = f.readlines()
+      if actual_output != expected_output:
+        print '[  FAILED  ] %s' % os.path.relpath(actual)
+        failed += 1
+        for line in difflib.unified_diff(expected_output, actual_output,
+                                         fromfile=os.path.relpath(expected),
+                                         tofile=os.path.relpath(actual)):
+          sys.stdout.write(line)
+        # Don't clean up the file on failure, so the results can be referenced
+        # more easily.
+        continue
+      print '[       OK ] %s' % os.path.relpath(actual)
+      passed += 1
+      os.remove(actual)
+
+    if failed == 0:
+      os.remove(compile_database)
+
+    print '[==========] %s ran.' % _NumberOfTestsToString(len(source_files))
+    if passed > 0:
+      print '[  PASSED  ] %s.' % _NumberOfTestsToString(passed)
+    if failed > 0:
+      print '[  FAILED  ] %s.' % _NumberOfTestsToString(failed)
+  finally:
+    # No matter what, unstage the git changes we made earlier to avoid polluting
+    # the index.
+    args = ['git', 'reset', '--quiet', 'HEAD']
+    args.extend(actual_files)
+    subprocess.call(args)
+
+
+if __name__ == '__main__':
+  sys.exit(main(sys.argv[1:]))