Add a module for tracking categories that metrics depend on.

tools/perf/benchmarks/metric_dependencies_unittest.py

+# Copyright 2016 The Chromium Authors. All rights reserved.

[benjhayden, 2017/03/02 21:33:35]

Drive-by nit: 2017

+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+import unittest
+
+from benchmarks import metric_dependencies
+from telemetry.timeline import chrome_trace_category_filter
+from telemetry.web_perf import timeline_based_measurement
+
+class TestMetricDependencies(unittest.TestCase):
+
+  def testIncludedCategory(self):
+    metric_dependencies.SetMetricDependenciesForTesting({
+      'metric1': [
+        'category1',
+        'disabled-by-default-category2',
+      ]
+    })
+    options = timeline_based_measurement.Options(
+        chrome_trace_category_filter.ChromeTraceCategoryFilter())
+    metric_dependencies.AugmentOptionsForMetrics(options, ['metric1'])
+    cat_filter = options.config.chrome_trace_config.category_filter
+    result = cat_filter.GetDictForChromeTracing()
+    self.assertEqual(result['included_categories'],
+        ['category1', 'disabled-by-default-category2'])
+
+  def testExcludedCategory(self):
+    metric_dependencies.SetMetricDependenciesForTesting({
+      'metric1': ['-category1']
+    })
+    options = timeline_based_measurement.Options(
+        chrome_trace_category_filter.ChromeTraceCategoryFilter())
+    metric_dependencies.AugmentOptionsForMetrics(options, ['metric1'])
+    cat_filter = options.config.chrome_trace_config.category_filter
+    result = cat_filter.GetDictForChromeTracing()
+    self.assertEqual(result['excluded_categories'], ['-category1'])
+
+  def testUnknownMetric(self):
+    metric_dependencies.SetMetricDependenciesForTesting({
+      'metric1': ['-category1']
+    })
+    options = timeline_based_measurement.Options(
+        chrome_trace_category_filter.ChromeTraceCategoryFilter())
+    self.assertRaises(AssertionError,
+        metric_dependencies.AugmentOptionsForMetrics, options, ['metric2'])