[benchmarking] Adds unit tests for results merger

Adding unit tests which is missing for results_merger.py.

Bug: chromium:1140389
Change-Id: Id12e952db5e90adb0343effee0d427ae6481a825
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2561640Reviewed-by: John Chen <johnchen@chromium.org>
Commit-Queue: Wenbin Zhang <wenbinzhang@google.com>
Cr-Commit-Position: refs/heads/master@{#831211}

tools/perf/core/results_merger_unittest.py

+# Copyright 2020 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 json
+import unittest
+
+from core import results_merger
+
+
+class ResultMergerTest(unittest.TestCase):
+  def setUp(self):
+    self.sample_json_string = '''
+    {
+      "interrupted": false,
+      "num_failures_by_type": {},
+      "seconds_since_epoch": 10.0,
+      "tests": {},
+      "version": 3
+    }
+    '''
+
+  def test_json_version_check_exception(self):
+    json_string = '{"seconds_since_epoch": 1.0, "version": 2}'
+    result = json.loads(json_string)
+    with self.assertRaises(results_merger.MergeException) as c:
+      results_merger.merge_test_results([result])
+    self.assertTrue(
+        'Unsupported version' in str(c.exception),
+        'Version check failure message is not in exception. Exception: %s' %
+        c.exception)
+
+  def test_json_required_field_check_exception(self):
+    json_string = '{"seconds_since_epoch": 1.0, "version": 3}'
+    result = json.loads(json_string)
+    with self.assertRaises(results_merger.MergeException) as c:
+      results_merger.merge_test_results([result])
+    self.assertTrue(
+        'Invalid json test results' in str(c.exception),
+        'Required key check failure message is not in exception. Exception: %s'
+        % c.exception)
+
+  def test_json_merge_tests(self):
+    result_1 = json.loads(self.sample_json_string)
+    result_2 = json.loads(self.sample_json_string)
+    result_3 = json.loads(self.sample_json_string)
+    result_1['tests'] = json.loads('''
+    {
+      "Benchmark-1": {
+        "Story-1": {
+          "actual": "PASS"
+        },
+        "Story-2": {
+          "actual": "SKIP"
+        }
+      }
+    }
+    ''')
+    result_2['tests'] = json.loads('''
+    {
+      "Benchmark-1": {
+        "Story-3": {
+          "actual": "FAIL"
+        }
+      },
+      "Benchmark-2": {
+        "Story-1": {
+          "actual": "SKIP"
+        }
+      }
+    }
+    ''')
+    result_3['tests'] = json.loads('''
+    {
+      "Benchmark-2": {
+        "Story-2": {
+          "actual": "PASS"
+        }
+      },
+      "Benchmark-3": {
+        "Story-1": {
+          "actual": "PASS"
+        }
+      }
+    }
+    ''')
+    merged_results = results_merger.merge_test_results(
+        [result_1, result_2, result_3])
+    self.assertEqual(len(merged_results['tests']), 3)
+    self.assertEqual(len(merged_results['tests']['Benchmark-1']), 3)
+    self.assertEqual(len(merged_results['tests']['Benchmark-2']), 2)
+    self.assertEqual(len(merged_results['tests']['Benchmark-3']), 1)
+
+  def test_json_merge_tests_non_dict_exception(self):
+    result_1 = json.loads(self.sample_json_string)
+    result_2 = json.loads(self.sample_json_string)
+    result_1['tests'] = json.loads('''
+      {
+        "Benchmark-1": {
+          "Story-1": {
+            "actual": "PASS"
+          }
+        }
+      }
+      ''')
+    result_2['tests'] = json.loads('''
+      {
+        "Benchmark-1": {
+          "Story-1": {
+            "actual": "FAIL"
+          }
+        }
+      }
+      ''')
+    with self.assertRaises(results_merger.MergeException) as c:
+      results_merger.merge_test_results([result_1, result_2])
+    self.assertTrue(
+        'not mergable' in str(c.exception),
+        'Merge failure message is not in exception. Exception: %s' %
+        c.exception)
+
+  def test_json_merge_interrupted(self):
+    result_1 = json.loads(self.sample_json_string)
+    result_2 = json.loads(self.sample_json_string)
+    result_2['interrupted'] = True
+    merged_results = results_merger.merge_test_results([result_1, result_2])
+    self.assertEqual(merged_results['interrupted'], True)
+
+  def test_json_merge_seconds_since_epoch(self):
+    result_1 = json.loads(self.sample_json_string)
+    result_2 = json.loads(self.sample_json_string)
+    result_2['seconds_since_epoch'] = 5.0
+    merged_results = results_merger.merge_test_results([result_1, result_2])
+    self.assertEqual(merged_results['seconds_since_epoch'], 5.0)
+
+  def test_json_merge_nums(self):
+    result_1 = json.loads(self.sample_json_string)
+    result_2 = json.loads(self.sample_json_string)
+    result_1['num_failures_by_type'] = json.loads('''
+    {
+      "PASS": 1,
+      "SKIP": 5
+    }
+    ''')
+    result_2['num_failures_by_type'] = json.loads('''
+    {
+      "PASS": 3,
+      "FAIL": 2
+    }
+    ''')
+    merged_results = results_merger.merge_test_results([result_1, result_2])
+    self.assertEqual(merged_results['num_failures_by_type']['PASS'], 4)
+    self.assertEqual(merged_results['num_failures_by_type']['SKIP'], 5)
+    self.assertEqual(merged_results['num_failures_by_type']['FAIL'], 2)