Replace recipes_test.py with a new parallel expectation-based test runner.

scripts/slave/unittests/expect_tests/cover.py

+# Copyright 2014 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 contextlib
+
+from cStringIO import StringIO
+
+import test_env  # pylint: disable=unused-import
+
+import coverage
+
+@contextlib.contextmanager
+def _cover(**kwargs):
+  c = coverage.coverage(**kwargs)
+  c._warn_no_data = False  # pylint: disable=protected-access
+  c.start()
+  try:
+    yield
+  finally:
+    c.stop()
+    c.save()
+
+
+@contextlib.contextmanager
+def _nop_cover():
+  yield
+
+class CoverageContext(object):
+  def __init__(self, includes, omits, enabled=True):
+    self.opts = None
+    self.cov = None
+    self.enabled = enabled
+
+    if enabled:
+      self.opts = {
+        'include': includes,
+        'omit': omits,
+        'data_suffix': True
+      }
+      self.cov = coverage.coverage(**self.opts)
+      self.cov.erase()
+
+  def cleanup(self):
+    if self.enabled:
+      self.cov.combine()
+
+  def report(self, verbose):
+    fail = False
+
+    if self.enabled:
+      outf = StringIO()
+      fail = self.cov.report(file=outf) != 100.0
+      summary = outf.getvalue().replace('%- 15s' % 'Name', 'Coverage Report', 1)
+      if verbose:
+        print
+        print summary
+      elif fail:
+        print
+        lines = summary.splitlines()
+        lines[2:-2] = [l for l in lines[2:-2]
+                       if not l.strip().endswith('100%')]
+        print '\n'.join(lines)
+        print
+        print 'FATAL: Test coverage is not at 100%.'
+
+    return not fail
+
+  def create_subprocess_context(self):

[Vadim Sh., 2014/04/02 22:37:59]

@contextlib.contextmanager
def create_subprocess_context(self):
  if not self.enabled:
    yield
  else:
    c = coverage.coverage(**self.opts)
    ...

?

I think it's shorter and cleaner overall.

[iannucci, 2014/04/03 00:03:49]

added comment and merged _cover and _nop_cover

+    if self.enabled:
+      return _cover(**self.opts)
+    else:
+      return _nop_cover()