Add a function to report perf results in JSON format.

Add support to report perf results in the JSON format specified in [1].

[1] https://github.com/catapult-project/catapult/blob/master/dashboard/docs/data-format.md


Bug: webrtc:8566
Change-Id: I25f829a4b012b3e2a3d56d61582a674f780148d0
Reviewed-on: https://webrtc-review.googlesource.com/26031
Reviewed-by: Patrik Höglund <phoglund@webrtc.org>
Reviewed-by: Karl Wiberg <kwiberg@webrtc.org>
Commit-Queue: Edward Lemur <ehmaldonado@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#20950}

test/testsupport/perf_test_unittest.cc

@@ -14,30 +14,97 @@
 
 #include "test/gtest.h"
 
+namespace {
+
+const char* kJsonExpected = R"({
+  "format_version":"1.0",
+  "charts":{
+    "foobar":{
+      "baz_v":{
+        "type":"scalar",
+        "value":7,
+        "units":"widgets"
+      },
+      "baz_me":{
+        "type":"list_of_scalars",
+        "values":[1],
+        "std":2,
+        "units":"lemurs"
+      },
+      "baz_vl":{
+        "type":"list_of_scalars",
+        "values":[1,2,3],
+        "units":"units"
+      }
+    },
+    "measurementmodifier":{
+      "trace":{
+        "type":"scalar",
+        "value":42,
+        "units":"units"
+      }
+    }
+  }
+})";
+
+std::string RemoveSpaces(std::string s) {
+  s.erase(std::remove(s.begin(), s.end(), ' '), s.end());
+  s.erase(std::remove(s.begin(), s.end(), '\n'), s.end());
+  return s;
+}
+
+}  // namespace
+
 namespace webrtc {
 namespace test {
 
+class PerfTest : public ::testing::Test {
+ protected:
+  void TearDown() override {
+    ClearPerfResults();
+  }
+};
+
+
 #if defined(WEBRTC_IOS)
-#define MAYBE_AppendResult DISABLED_AppendResult
+#define MAYBE_TestPrintResult DISABLED_TestPrintResult
 #else
-#define MAYBE_AppendResult AppendResult
+#define MAYBE_TestPrintResult TestPrintResult
 #endif
-TEST(PerfTest, MAYBE_AppendResult) {
+TEST_F(PerfTest, MAYBE_TestPrintResult) {
   testing::internal::CaptureStdout();
-  std::string expected = "RESULT measurementmodifier: trace= 42 units\n";
+  std::string expected;
+
+  expected += "RESULT measurementmodifier: trace= 42 units\n";
   PrintResult("measurement", "modifier", "trace", 42, "units", false);
 
-  expected += "*RESULT foobar: baz= 7 widgets\n";
-  PrintResult("foo", "bar", "baz", 7, "widgets", true);
+  expected += "*RESULT foobar: baz_v= 7 widgets\n";
+  PrintResult("foo", "bar", "baz_v", 7, "widgets", true);
 
-  expected += "RESULT foobar: baz= {1,2} lemurs\n";
-  PrintResultMeanAndError("foo", "bar", "baz", 1, 2, "lemurs", false);
+  expected += "RESULT foobar: baz_me= {1,2} lemurs\n";
+  PrintResultMeanAndError("foo", "bar", "baz_me", 1, 2, "lemurs", false);
 
-  expected += "RESULT foobar: baz= [1,2,3] units\n";
-  PrintResultList("foo", "bar", "baz", {1, 2, 3}, "units", false);
+  const double kListOfScalars[] = {1, 2, 3};
+  expected += "RESULT foobar: baz_vl= [1,2,3] units\n";
+  PrintResultList("foo", "bar", "baz_vl", kListOfScalars, "units", false);
 
-  std::string output = testing::internal::GetCapturedStdout();
-  EXPECT_EQ(expected, output);
+  EXPECT_EQ(expected, testing::internal::GetCapturedStdout());
+}
+
+TEST_F(PerfTest, TestGetPerfResultsJSON) {
+  PrintResult("measurement", "modifier", "trace", 42, "units", false);
+  PrintResult("foo", "bar", "baz_v", 7, "widgets", true);
+  PrintResultMeanAndError("foo", "bar", "baz_me", 1, 2, "lemurs", false);
+  const double kListOfScalars[] = {1, 2, 3};
+  PrintResultList("foo", "bar", "baz_vl", kListOfScalars, "units", false);
+
+  EXPECT_EQ(RemoveSpaces(kJsonExpected), GetPerfResultsJSON());
+}
+
+TEST_F(PerfTest, TestClearPerfResults) {
+  PrintResult("measurement", "modifier", "trace", 42, "units", false);
+  ClearPerfResults();
+  EXPECT_EQ(R"({"format_version":"1.0","charts":{}})", GetPerfResultsJSON());
 }
 
 }  // namespace test