[Telemetry] Enable screenshot taking on Mac

tools/telemetry/telemetry/core/platform_unittest.py

Index: tools/telemetry/telemetry/core/platform_unittest.py
diff --git a/tools/telemetry/telemetry/core/platform_unittest.py b/tools/telemetry/telemetry/core/platform_unittest.py
new file mode 100644
index 0000000000000000000000000000000000000000..409d86991cf5531ed7d17138dc9fd6039a17c61c
--- /dev/null
+++ b/tools/telemetry/telemetry/core/platform_unittest.py
@@ -0,0 +1,42 @@
+# 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.
+
+import os
+import tempfile
+
+from telemetry import decorators
+from telemetry.core import os_version
+from telemetry.util import image_util
+from telemetry.testing import tab_test_case
+
+
+class PlatformScreenshotTest(tab_test_case.TabTestCase):
+  def testScreenshotSupported(self):
+    if self._platform.GetOSName() == 'android':
+      self.assertTrue(self._platform.CanTakeScreenshot())
+
+  # Run this test in serial to avoid multiple browsers pop up on the screen.
+  @decorators.Isolated
+  def testScreenshot(self):
+    if not self._platform.CanTakeScreenshot():
+      self.skipTest('Platform does not support screenshots, skipping test.')
+    # Skip the test on Mac 10.5, 10.6, 10.7 because png format isn't
+    # recognizable on Mac < 10.8 (crbug.com/369490#c13)
+    if (self._platform.GetOSName() == 'mac' and
+        self._platform.GetOSVersionName() in (
+            os_version.LEOPARD, os_version.SNOWLEOPARD, os_version.LION)):
+      self.skipTest('OS X version %s too old' % self._platform.GetOSName())
+    tf = tempfile.NamedTemporaryFile(delete=False, suffix='.png')
+    tf.close()
+    try:
+      self.Navigate('screenshot_test.html')
+      self._platform.TakeScreenshot(tf.name)
+      # Assert that screenshot image contains the color of the triangle defined
+      # in screenshot_test.html.
+      img = image_util.FromPngFile(tf.name)
+      screenshot_pixels = image_util.Pixels(img)
+      special_colored_pixel = bytearray([217, 115, 43])
+      self.assertTrue(special_colored_pixel in screenshot_pixels)
+    finally:
+      os.remove(tf.name)