Parallelize run_corpus_tests.py.

testing/tools/pngdiffer.py

Index: testing/tools/pngdiffer.py
diff --git a/testing/tools/pngdiffer.py b/testing/tools/pngdiffer.py
index 35eaaa437a3d48f68bb4f7ffd31440aac78c4c30..bef252674f09d848a37448afb099fb2dd54b1577 100755
--- a/testing/tools/pngdiffer.py
+++ b/testing/tools/pngdiffer.py
@@ -4,9 +4,10 @@
 # found in the LICENSE file.
 
 import os
-import subprocess
 import sys
 
+import common
+
 class PNGDiffer():
   ACTUAL_TEMPLATE = '.pdf.%d.png'
   EXPECTED_TEMPLATE = '_expected' + ACTUAL_TEMPLATE
@@ -37,33 +38,33 @@ class PNGDiffer():
       i += 1
     return actual_paths
 
-  def HasDifferences(self, input_filename, source_dir, working_dir):
+  def HasDifferences(self, input_filename, source_dir, working_dir,
+                     redirect_output=False):
     template_paths = self._GetTemplatePaths(
         input_filename, source_dir, working_dir)
     actual_path_template = template_paths[0];
     expected_path_template = template_paths[1]
     platform_expected_path_template = template_paths[2]
     i = 0
-    try:
-      while True:
-        actual_path = actual_path_template % i
-        expected_path = expected_path_template % i
-        platform_expected_path = (
-            platform_expected_path_template % (self.os_name, i))
-        if os.path.exists(platform_expected_path):
-          expected_path = platform_expected_path
-        elif not os.path.exists(expected_path):
-          if i == 0:
-            print "WARNING: no expected results files for " + input_filename
-          break
-        print "Checking " + actual_path
-        sys.stdout.flush()
-        subprocess.check_call(
-            [self.pdfium_diff_path, expected_path, actual_path])
-        i += 1
-    except subprocess.CalledProcessError as e:
-      print "FAILURE: " + input_filename + "; " + str(e)
-      return True
+    while True:
+      actual_path = actual_path_template % i
+      expected_path = expected_path_template % i
+      platform_expected_path = (
+          platform_expected_path_template % (self.os_name, i))
+      if os.path.exists(platform_expected_path):
+        expected_path = platform_expected_path
+      elif not os.path.exists(expected_path):
+        if i == 0:
+          print "WARNING: no expected results files for " + input_filename
+        break
+      print "Checking " + actual_path
+      sys.stdout.flush()
+      error = common.RunCommand(
+          [self.pdfium_diff_path, expected_path, actual_path], redirect_output)
+      if error:
+        print "FAILURE: " + input_filename + "; " + str(error)
+        return True
+      i += 1
     return False
 
   def _GetTemplatePaths(self, input_filename, source_dir, working_dir):