[tools/perf] Add unittests coverage for system health benchmarks

tools/perf/benchmarks/system_health_unittest.py

+# Copyright 2016 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 sys
+import unittest
+
+from benchmarks import system_health as system_health_benchmark
+from core import path_util
+from page_sets.system_health import system_health_stories
+
+from telemetry import benchmark as benchmark_module
+from telemetry.core import discover
+
+
+def _GetAllSystemHealthBenchmarks():
+  all_perf_benchmarks = discover.DiscoverClasses(
+      path_util.GetPerfBenchmarksDir(), path_util.GetPerfDir(),
+      benchmark_module.Benchmark,
+      index_by_class_name=True).values()
+  return [b for b in all_perf_benchmarks if
+          sys.modules[b.__module__] == system_health_benchmark]
+
+
+class TestSystemHealthBenchmarks(unittest.TestCase):
+
+  def testNamePrefix(self):
+    for b in _GetAllSystemHealthBenchmarks():
+      self.assertTrue(
+          b.Name().startswith('system_health.'),
+          '%r must have name starting with "system_health." prefix' % b)
+
+  def testShouldTearDownStateAfterEachStoryRunIsTrue(self):
+    for b in _GetAllSystemHealthBenchmarks():
+      self.assertTrue(
+          b.ShouldTearDownStateAfterEachStoryRun(),
+          '%r has ShouldTearDownStateAfterEachStoryRun set to False' % b)
+
+  def testSystemHealthStorySetIsUsed(self):
+    for b in _GetAllSystemHealthBenchmarks():
+      if b is system_health_benchmark.WebviewStartupSystemHealthBenchmark:
+        continue
+      self.assertIsInstance(
+          b().CreateStorySet(None),
+          system_health_stories.SystemHealthStorySet,
+          '%r does not use SystemHealthStorySet' % b)