Adding tracing and gtest pretty printing support to TestPendingTask.

These functions where invaluable when trying to debug and fix the
cc::OrderedTestRunner as they let me easily inspect the tasks without having to
fire up GDB. They should also be useful in development / testing of other task
runners.

Added a very simple test for ShouldRunBefore which shows this stuff working. If
that test fails, the output looks like the following;
-------------------------------------------------------------------------------
../../base/test/test_pending_task_unittest.cc:49: Failure
Value of: task_after.ShouldRunBefore(task_first)
  Actual: false
Expected: true
TestPendingTask(
  {"delay":2000,"nestability":"NESTABLE","post_time":0,
   "posting_function":"Unknown@Unknown:-1","run_at":2000}
).ShouldRunBefore(TestPendingTask(
  {"delay":1000,"nestability":"NESTABLE","post_time":0,
   "posting_function":"Unknown@Unknown:-1","run_at":1000})
)
-------------------------------------------------------------------------------

BUG=380889

Review URL: https://codereview.chromium.org/491743002

Cr-Commit-Position: refs/heads/master@{#292370}

1 files changed, 55 insertions, 0 deletions

diff --git a/base/test/test_pending_task_unittest.cc b/base/test/test_pending_task_unittest.cc
new file mode 100644
index 0000000..4a6bd242
--- /dev/null
+++ b/base/test/test_pending_task_unittest.cc
@@ -0,0 +1,55 @@
+// Copyright (c) 2012 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.
+
+#include "base/test/test_pending_task.h"
+
+#include "base/bind.h"
+#include "base/debug/trace_event.h"
+#include "testing/gmock/include/gmock/gmock.h"
+#include "testing/gtest/include/gtest/gtest-spi.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace {
+
+TEST(TestPendingTaskTest, TraceSupport) {
+  base::TestPendingTask task;
+
+  // Check that TestPendingTask can be sent to the trace subsystem.
+  TRACE_EVENT1("test", "TestPendingTask::TraceSupport", "task", task.AsValue());
+
+  // Just a basic check that the trace output has *something* in it.
+  EXPECT_THAT(task.AsValue()->ToString(), ::testing::HasSubstr("post_time"));
+}
+
+TEST(TestPendingTaskTest, ToString) {
+  base::TestPendingTask task;
+
+  // Just a basic check that ToString has *something* in it.
+  EXPECT_THAT(task.ToString(), ::testing::StartsWith("TestPendingTask("));
+}
+
+TEST(TestPendingTaskTest, GTestPrettyPrint) {
+  base::TestPendingTask task;
+
+  // Check that gtest is calling the TestPendingTask's PrintTo method.
+  EXPECT_THAT(::testing::PrintToString(task),
+              ::testing::StartsWith("TestPendingTask("));
+
+  // Check that pretty printing works with the gtest iostreams operator.
+  EXPECT_NONFATAL_FAILURE(EXPECT_TRUE(false) << task, "TestPendingTask(");
+}
+
+TEST(TestPendingTaskTest, ShouldRunBefore) {
+  base::TestPendingTask task_first;
+  task_first.delay = base::TimeDelta::FromMilliseconds(1);
+  base::TestPendingTask task_after;
+  task_after.delay = base::TimeDelta::FromMilliseconds(2);
+
+  EXPECT_FALSE(task_after.ShouldRunBefore(task_first))
+      << task_after << ".ShouldRunBefore(" << task_first << ")\n";
+  EXPECT_TRUE(task_first.ShouldRunBefore(task_after))
+      << task_first << ".ShouldRunBefore(" << task_after << ")\n";
+}
+
+}  // namespace