Android: adds instrumentation test runners.

build/android/pylib/python_test_caller.py

+# 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.
+
+"""Helper module for calling python-based tests."""
+
+
+import logging
+import sys
+import time
+
+from test_result import TestResults
+
+
+def CallPythonTest(test, device_id, shard_index):
+  """Invokes a test function and translates Python exceptions into test results.
+
+  This method invokes SetUp()/TearDown() on the test. It is intended to be
+  resilient to exceptions in SetUp(), the test itself, and TearDown(). Any
+  Python exception means the test is marked as failed, and the test result will
+  contain information about the exception.
+
+  If SetUp() raises an exception, the test is not run.
+
+  If TearDown() raises an exception, the test is treated as a failure. However,
+  if the test itself raised an exception beforehand, that stack trace will take
+  precedence whether or not TearDown() also raised an exception.
+
+  shard_index is not applicable in single-device scenarios, when test execution
+  is serial rather than parallel. Tests can use this to bring up servers with
+  unique port numbers, for example. See also python_test_sharder.
+
+  Args:
+    test: an object which is ostensibly a subclass of PythonTestBase.
+    device_id: device ID against which the test will run.
+    shard_index: index # of the shard on which this test is running
+
+  Returns:
+    A TestResults object which contains any results produced by the test or, in
+    the case of a Python exception, the Python exception info.
+  """
+
+  start_date_ms = int(time.time()) * 1000
+  failed = False
+
+  try:
+    test.SetUp(device_id, shard_index)
+  except Exception:
+    failed = True
+    logging.exception(
+        'Caught exception while trying to run SetUp() for test: ' +
+        test.qualified_name)
+    # Tests whose SetUp() method has failed are likely to fail, or at least
+    # yield invalid results.
+    exc_info = sys.exc_info()
+    return TestResults.FromPythonException(test.qualified_name, start_date_ms,
+                                           exc_info)
+
+  try:
+    result = test.Run()
+  except Exception:
+    # Setting this lets TearDown() avoid stomping on our stack trace from Run()
+    # should TearDown() also raise an exception.
+    failed = True
+    logging.exception('Caught exception while trying to run test: ' +
+                      test.qualified_name)
+    exc_info = sys.exc_info()
+    result = TestResults.FromPythonException(test.qualified_name, start_date_ms,
+                                             exc_info)
+
+  try:
+    test.TearDown()
+  except Exception:
+    logging.exception(
+        'Caught exception while trying run TearDown() for test: ' +
+        test.qualified_name)
+    if not failed:
+      # Don't stomp the error during the test if TearDown blows up. This is a
+      # trade-off: if the test fails, this will mask any problem with TearDown
+      # until the test is fixed.
+      exc_info = sys.exc_info()
+      result = TestResults.FromPythonException(test.qualified_name,
+                                               start_date_ms, exc_info)
+
+  return result