Allow running individual tests.

testing/tools/run_corpus_tests.py

 #!/usr/bin/env python
 # Copyright 2015 The PDFium 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 cStringIO
 import functools
 import multiprocessing
 import optparse
 import os
@@ skipping 86 matching lines @@
 
   test_suppressor = suppressor.Suppressor(finder)
   image_differ = pngdiffer.PNGDiffer(finder)
 
   # test files are under .../pdfium/testing/corpus.
   failures = []
   surprises = []
   walk_from_dir = finder.TestingDir('corpus');
   input_file_re = re.compile('^[a-zA-Z0-9_.]+[.]pdf$')
   test_cases = []
-  for source_dir, _, filename_list in os.walk(walk_from_dir):
-    for input_filename in filename_list:
-      if input_file_re.match(input_filename):
-        input_path = os.path.join(source_dir, input_filename)
-        if os.path.isfile(input_path):
-          test_cases.append((input_filename, source_dir))
 
-  if options.num_workers > 1:
+  if len(args):
+    for file_name in args:
+      input_path = os.path.join(walk_from_dir, file_name)
+      if not os.path.isfile(input_path):
+        print "Can't find test file '%s'" % file_name
+        return 1
+
+      test_cases.append((os.path.basename(input_path),
+                         os.path.dirname(input_path)))
+  else:
+    for source_dir, _, filename_list in os.walk(walk_from_dir):
+      for input_filename in filename_list:
+        if input_file_re.match(input_filename):
+          input_path = os.path.join(source_dir, input_filename)
+          if os.path.isfile(input_path):
+            test_cases.append((input_filename, source_dir))
+
+  if options.num_workers > 1 and len(test_cases) > 1:
     try:
       pool = multiprocessing.Pool(options.num_workers)
       worker_func = functools.partial(test_one_file_parallel, working_dir,
                                       pdfium_test_path, image_differ)
       worker_results = pool.imap(worker_func, test_cases)
       for worker_result in worker_results:
         result, output, input_filename, source_dir = worker_result
         input_path = os.path.join(source_dir, input_filename)
         sys.stdout.write(output)
         handle_result(test_suppressor, input_filename, input_path, result,
@@ skipping 22 matching lines @@
     print '\n\nSummary of Failures:'
     for failure in failures:
       print failure
     return 1
 
   return 0
 
 
 if __name__ == '__main__':
   sys.exit(main())