// Copyright 2014 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.
#ifndef NET_QUIC_TEST_TOOLS_SCOPED_MOCK_LOG_H_
#define NET_QUIC_TEST_TOOLS_SCOPED_MOCK_LOG_H_
#include "base/logging.h"
#include "testing/gmock/include/gmock/gmock.h"
#include "testing/gtest/include/gtest/gtest.h"
namespace net {
namespace test {
// A ScopedMockLog object intercepts LOG() messages issued during its
// lifespan. Using this together with gMock, it's very easy to test
// how a piece of code calls LOG(). The typical usage:
//
// TEST(FooTest, LogsCorrectly) {
// ScopedMockLog log;
//
// // We expect the WARNING "Something bad!" exactly twice.
// EXPECT_CALL(log, Log(WARNING, _, "Something bad!"))
// .Times(2);
//
// // We allow foo.cc to call LOG(INFO) any number of times.
// EXPECT_CALL(log, Log(INFO, HasSubstr("/foo.cc"), _))
// .Times(AnyNumber());
//
// log.StartCapturingLogs(); // Call this after done setting expectations.
// Foo(); // Exercises the code under test.
// }
//
// CAVEAT: base/logging does not allow a thread to call LOG() again
// when it's already inside a LOG() call. Doing so will cause a
// deadlock. Therefore, it's the user's responsibility to not call
// LOG() in an action triggered by ScopedMockLog::Log(). You may call
// RAW_LOG() instead.
class ScopedMockLog {
public:
// Creates a ScopedMockLog object that is not capturing logs.
// If it were to start to capture logs, it could be a problem if
// some other threads already exist and are logging, as the user
// hasn't had a chance to set up expectation on this object yet
// (calling a mock method before setting the expectation is
// UNDEFINED behavior).
ScopedMockLog();
// When the object is destructed, it stops intercepting logs.
~ScopedMockLog();
// Starts log capturing if the object isn't already doing so.
// Otherwise crashes. Usually this method is called in the same
// thread that created this object. It is the user's responsibility
// to not call this method if another thread may be calling it or
// StopCapturingLogs() at the same time.
void StartCapturingLogs();
// Stops log capturing if the object is capturing logs. Otherwise
// crashes. Usually this method is called in the same thread that
// created this object. It is the user's responsibility to not call
// this method if another thread may be calling it or
// StartCapturingLogs() at the same time.
void StopCapturingLogs();
// Sets the Log Message Handler that gets passed every log message before
// it's sent to other log destinations (if any).
// Returns true to signal that it handled the message and the message
// should not be sent to other log destinations.
MOCK_METHOD5(Log, bool(int severity,
const char* file,
int line,
size_t message_start,
const std::string& str));
private:
// The currently active scoped mock log.
static ScopedMockLog* g_instance_;
// Static function which is set as the logging message handler.
// Called once for each message.
static bool LogMessageHandler(int severity,
const char* file,
int line,
size_t message_start,
const std::string& str);
// True if this object is currently capturing logs.
bool is_capturing_logs_;
// The previous handler to restore when the ScopedMockLog is destroyed.
logging::LogMessageHandlerFunction previous_handler_;
};
} // namespace test
} // namespace net
#endif // NET_QUIC_TEST_TOOLS_SCOPED_MOCK_LOG_H_