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1 // Copyright 2009 Google Inc. All Rights Reserved.
2 //
3 // Redistribution and use in source and binary forms, with or without
4 // modification, are permitted provided that the following conditions are
5 // met:
6 //
7 //     * Redistributions of source code must retain the above copyright
8 // notice, this list of conditions and the following disclaimer.
9 //     * Redistributions in binary form must reproduce the above
10 // copyright notice, this list of conditions and the following disclaimer
11 // in the documentation and/or other materials provided with the
12 // distribution.
13 //     * Neither the name of Google Inc. nor the names of its
14 // contributors may be used to endorse or promote products derived from
15 // this software without specific prior written permission.
16 //
17 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
18 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
19 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
20 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
21 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
22 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
23 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
24 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
25 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
26 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
27 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28 //
29 // Author: vladl@google.com (Vlad Losev)
30 
31 // This sample shows how to use Google Test listener API to implement
32 // a primitive leak checker.
33 
34 #include <stdio.h>
35 #include <stdlib.h>
36 
37 #include "gtest/gtest.h"
38 
39 using ::testing::EmptyTestEventListener;
40 using ::testing::InitGoogleTest;
41 using ::testing::Test;
42 using ::testing::TestCase;
43 using ::testing::TestEventListeners;
44 using ::testing::TestInfo;
45 using ::testing::TestPartResult;
46 using ::testing::UnitTest;
47 
48 namespace {
49 
50 // We will track memory used by this class.
51 class Water {
52  public:
53   // Normal Water declarations go here.
54 
55   // operator new and operator delete help us control water allocation.
operator new(size_t allocation_size)56   void* operator new(size_t allocation_size) {
57     allocated_++;
58     return malloc(allocation_size);
59   }
60 
operator delete(void * block,size_t)61   void operator delete(void* block, size_t /* allocation_size */) {
62     allocated_--;
63     free(block);
64   }
65 
allocated()66   static int allocated() { return allocated_; }
67 
68  private:
69   static int allocated_;
70 };
71 
72 int Water::allocated_ = 0;
73 
74 // This event listener monitors how many Water objects are created and
75 // destroyed by each test, and reports a failure if a test leaks some Water
76 // objects. It does this by comparing the number of live Water objects at
77 // the beginning of a test and at the end of a test.
78 class LeakChecker : public EmptyTestEventListener {
79  private:
80   // Called before a test starts.
OnTestStart(const TestInfo &)81   virtual void OnTestStart(const TestInfo& /* test_info */) {
82     initially_allocated_ = Water::allocated();
83   }
84 
85   // Called after a test ends.
OnTestEnd(const TestInfo &)86   virtual void OnTestEnd(const TestInfo& /* test_info */) {
87     int difference = Water::allocated() - initially_allocated_;
88 
89     // You can generate a failure in any event handler except
90     // OnTestPartResult. Just use an appropriate Google Test assertion to do
91     // it.
92     EXPECT_LE(difference, 0) << "Leaked " << difference << " unit(s) of Water!";
93   }
94 
95   int initially_allocated_;
96 };
97 
TEST(ListenersTest,DoesNotLeak)98 TEST(ListenersTest, DoesNotLeak) {
99   Water* water = new Water;
100   delete water;
101 }
102 
103 // This should fail when the --check_for_leaks command line flag is
104 // specified.
TEST(ListenersTest,LeaksWater)105 TEST(ListenersTest, LeaksWater) {
106   Water* water = new Water;
107   EXPECT_TRUE(water != NULL);
108 }
109 
110 }  // namespace
111 
main(int argc,char ** argv)112 int main(int argc, char **argv) {
113   InitGoogleTest(&argc, argv);
114 
115   bool check_for_leaks = false;
116   if (argc > 1 && strcmp(argv[1], "--check_for_leaks") == 0 )
117     check_for_leaks = true;
118   else
119     printf("%s\n", "Run this program with --check_for_leaks to enable "
120            "custom leak checking in the tests.");
121 
122   // If we are given the --check_for_leaks command line flag, installs the
123   // leak checker.
124   if (check_for_leaks) {
125     TestEventListeners& listeners = UnitTest::GetInstance()->listeners();
126 
127     // Adds the leak checker to the end of the test event listener list,
128     // after the default text output printer and the default XML report
129     // generator.
130     //
131     // The order is important - it ensures that failures generated in the
132     // leak checker's OnTestEnd() method are processed by the text and XML
133     // printers *before* their OnTestEnd() methods are called, such that
134     // they are attributed to the right test. Remember that a listener
135     // receives an OnXyzStart event *after* listeners preceding it in the
136     // list received that event, and receives an OnXyzEnd event *before*
137     // listeners preceding it.
138     //
139     // We don't need to worry about deleting the new listener later, as
140     // Google Test will do it.
141     listeners.Append(new LeakChecker);
142   }
143   return RUN_ALL_TESTS();
144 }
145