michael@0: // Copyright 2009 Google Inc. All Rights Reserved.
michael@0: //
michael@0: // Redistribution and use in source and binary forms, with or without
michael@0: // modification, are permitted provided that the following conditions are
michael@0: // met:
michael@0: //
michael@0: //     * Redistributions of source code must retain the above copyright
michael@0: // notice, this list of conditions and the following disclaimer.
michael@0: //     * Redistributions in binary form must reproduce the above
michael@0: // copyright notice, this list of conditions and the following disclaimer
michael@0: // in the documentation and/or other materials provided with the
michael@0: // distribution.
michael@0: //     * Neither the name of Google Inc. nor the names of its
michael@0: // contributors may be used to endorse or promote products derived from
michael@0: // this software without specific prior written permission.
michael@0: //
michael@0: // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
michael@0: // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
michael@0: // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
michael@0: // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
michael@0: // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
michael@0: // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
michael@0: // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
michael@0: // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
michael@0: // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
michael@0: // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
michael@0: // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
michael@0: //
michael@0: // Author: vladl@google.com (Vlad Losev)
michael@0: 
michael@0: // This sample shows how to use Google Test listener API to implement
michael@0: // a primitive leak checker.
michael@0: 
michael@0: #include <stdio.h>
michael@0: #include <stdlib.h>
michael@0: 
michael@0: #include "gtest/gtest.h"
michael@0: 
michael@0: using ::testing::EmptyTestEventListener;
michael@0: using ::testing::InitGoogleTest;
michael@0: using ::testing::Test;
michael@0: using ::testing::TestCase;
michael@0: using ::testing::TestEventListeners;
michael@0: using ::testing::TestInfo;
michael@0: using ::testing::TestPartResult;
michael@0: using ::testing::UnitTest;
michael@0: 
michael@0: namespace {
michael@0: 
michael@0: // We will track memory used by this class.
michael@0: class Water {
michael@0:  public:
michael@0:   // Normal Water declarations go here.
michael@0: 
michael@0:   // operator new and operator delete help us control water allocation.
michael@0:   void* operator new(size_t allocation_size) {
michael@0:     allocated_++;
michael@0:     return malloc(allocation_size);
michael@0:   }
michael@0: 
michael@0:   void operator delete(void* block, size_t /* allocation_size */) {
michael@0:     allocated_--;
michael@0:     free(block);
michael@0:   }
michael@0: 
michael@0:   static int allocated() { return allocated_; }
michael@0: 
michael@0:  private:
michael@0:   static int allocated_;
michael@0: };
michael@0: 
michael@0: int Water::allocated_ = 0;
michael@0: 
michael@0: // This event listener monitors how many Water objects are created and
michael@0: // destroyed by each test, and reports a failure if a test leaks some Water
michael@0: // objects. It does this by comparing the number of live Water objects at
michael@0: // the beginning of a test and at the end of a test.
michael@0: class LeakChecker : public EmptyTestEventListener {
michael@0:  private:
michael@0:   // Called before a test starts.
michael@0:   virtual void OnTestStart(const TestInfo& /* test_info */) {
michael@0:     initially_allocated_ = Water::allocated();
michael@0:   }
michael@0: 
michael@0:   // Called after a test ends.
michael@0:   virtual void OnTestEnd(const TestInfo& /* test_info */) {
michael@0:     int difference = Water::allocated() - initially_allocated_;
michael@0: 
michael@0:     // You can generate a failure in any event handler except
michael@0:     // OnTestPartResult. Just use an appropriate Google Test assertion to do
michael@0:     // it.
michael@0:     EXPECT_LE(difference, 0) << "Leaked " << difference << " unit(s) of Water!";
michael@0:   }
michael@0: 
michael@0:   int initially_allocated_;
michael@0: };
michael@0: 
michael@0: TEST(ListenersTest, DoesNotLeak) {
michael@0:   Water* water = new Water;
michael@0:   delete water;
michael@0: }
michael@0: 
michael@0: // This should fail when the --check_for_leaks command line flag is
michael@0: // specified.
michael@0: TEST(ListenersTest, LeaksWater) {
michael@0:   Water* water = new Water;
michael@0:   EXPECT_TRUE(water != NULL);
michael@0: }
michael@0: 
michael@0: }  // namespace
michael@0: 
michael@0: int main(int argc, char **argv) {
michael@0:   InitGoogleTest(&argc, argv);
michael@0: 
michael@0:   bool check_for_leaks = false;
michael@0:   if (argc > 1 && strcmp(argv[1], "--check_for_leaks") == 0 )
michael@0:     check_for_leaks = true;
michael@0:   else
michael@0:     printf("%s\n", "Run this program with --check_for_leaks to enable "
michael@0:            "custom leak checking in the tests.");
michael@0: 
michael@0:   // If we are given the --check_for_leaks command line flag, installs the
michael@0:   // leak checker.
michael@0:   if (check_for_leaks) {
michael@0:     TestEventListeners& listeners = UnitTest::GetInstance()->listeners();
michael@0: 
michael@0:     // Adds the leak checker to the end of the test event listener list,
michael@0:     // after the default text output printer and the default XML report
michael@0:     // generator.
michael@0:     //
michael@0:     // The order is important - it ensures that failures generated in the
michael@0:     // leak checker's OnTestEnd() method are processed by the text and XML
michael@0:     // printers *before* their OnTestEnd() methods are called, such that
michael@0:     // they are attributed to the right test. Remember that a listener
michael@0:     // receives an OnXyzStart event *after* listeners preceding it in the
michael@0:     // list received that event, and receives an OnXyzEnd event *before*
michael@0:     // listeners preceding it.
michael@0:     //
michael@0:     // We don't need to worry about deleting the new listener later, as
michael@0:     // Google Test will do it.
michael@0:     listeners.Append(new LeakChecker);
michael@0:   }
michael@0:   return RUN_ALL_TESTS();
michael@0: }