Introduce new basic playback test.

chrome/test/functional/media/media_test_utils.py

+#!/usr/bin/env python
+# Copyright (c) 2012 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 functools

[Ami GONE FROM CHROMIUM, 2012/01/25 17:58:48]

missing newline

[DaleCurtis, 2012/01/25 23:59:25]

Done.

+
+
+def FindMediaFiles(matrix, criteria=None, **kwargs):
+  """Given a loosely structured test matrix, finds media matching criteria.

[Ami GONE FROM CHROMIUM, 2012/01/25 17:58:48]

This whole thing seems like crazy overkill to me.

[DaleCurtis, 2012/01/25 23:59:25]

You should have seen the generic version :)  In any case, I wrote it with the
intent that we'll eventually have a very large test matrix where metadata
filtering will be important.

[Ami GONE FROM CHROMIUM, 2012/01/26 00:07:23]

WDYT about keeping this matrix business in your back-pocket for that glorious
future, and making this CL just about making the one video play? 

+
+  The only requirements for the test matrix structure are a top level element
+  and a 'files' list element under it containing dicts with at least a 'file'
+  tag, indicating the file name, in them.  For example:
+
+      {
+        "<test name>": {
+          <...any tags...>
+
+          'files': [
+            {'file': '<filename>', <...any tags...>}
+          ]
+        }
+      }
+
+  Any kind of metadata can be added in the any tags sections.  All fields can be
+  filtered on using the criteria mechanism.  For example, to match only files
+  with the name 'test.mp4' you would write:
+
+      FindMediaFiles(<matrix>, file='test.mp4')
+
+  If you wanted to ensure that a metadata named 'duration' was < 5.0 you can use
+  the criteria system:
+
+      FindMediaFiles(<matrix>, criteria={'duration': lambda v: v < 5.0})
+
+  Arguments:
+    matrix: Dictionary object as described above.
+    criteria: Dictionary of tags to boolean functions.  Each file entry in the
+      matrix will be required to have the specified tags and pass the associated
+      function.  The function will be called with the value associated with the
+      tag.
+    **kwargs: Generally a simple equality check is all that is required to find
+      the required tags.  So by simply specifying the key and value here, you
+      can avoid typing out a full criteria entry.  Entries here will override
+      those in |criteria|.
+  """
+  results = []
+
+  # Automatically covert each kwarg into a simple equality check.
+  criteria = criteria or {}
+  for arg in kwargs:
+    criteria[arg] = functools.partial(lambda x, y: x == y, kwargs[arg])
+
+  for entry in matrix:
+    # Make a shallow copy so we don't destroy the main data structure.
+    test = matrix[entry].copy()
+
+    # Insert the entry name into the dictionary so it can be filtered on.
+    test.setdefault('name', entry)
+
+    # Remove the files key from the top level test structure.
+    for f in test.pop('files'):
+      # Setup default values for files.
+      f.setdefault('audio', True)
+      f.setdefault('video', True)
+
+      # Copy in the top level tags from test into the file dictionary.
+      f.update(test)
+
+      # Ensure that all the file tags pass all the criteria.
+      success = True
+      for tag, fn in criteria.iteritems():
+        success = success and tag in f and fn(f[tag])
+
+      if success:
+        results.append(f['file'])
+
+  return results