[Android] Split DeviceUtils tests and run them in presubmit.

build/android/PRESUBMIT.py

Index: build/android/PRESUBMIT.py
diff --git a/build/android/PRESUBMIT.py b/build/android/PRESUBMIT.py
index 4e25896f27ab95a424636bfc0e15289ab09820bf..4e77b5b037335daf5505bb5cdc144e74773655c9 100644
--- a/build/android/PRESUBMIT.py
+++ b/build/android/PRESUBMIT.py
@@ -50,6 +50,18 @@ def CommonChecks(input_api, output_api):
 
   output.extend(input_api.canned_checks.RunUnitTestsInDirectory(
       input_api, output_api, J('buildbot', 'tests')))
+
+  pylib_test_env = dict(input_api.environ)
+  pylib_test_env.update({
+      'PYTHONPATH': input_api.PresubmitLocalPath(),
+      'PYTHONDONTWRITEBYTECODE': '1',
+  })
+  output.extend(input_api.canned_checks.RunUnitTests(

[frankf, 2014/07/10 17:45:09]

Why not run all pylib unit tests on the bots? These tests are likely going to
get larger in the future, not sure it makes sense to run them during presubmit.
I think tools like telemetry run their unittests on the bots, right?

[jbudorick, 2014/07/10 18:08:49]

I think that should be our goal. Even with that, though, I don't particularly
see a problem in running tests that are "fast enough" -- an admittedly slippery
distinction -- in presubmit.

(fwiw, the DeviceUtils tests currently run in ~1/3s, and I don't anticipate them
taking longer than 1s when finished.)

+      input_api,
+      output_api,
+      unit_tests=[
+          J('pylib', 'device', 'device_utils_test.py'),],
+      env=pylib_test_env))
   output.extend(_CheckDeletionsOnlyFiles(input_api, output_api))
   return output