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 // This sample shows how to use Google Test listener API to implement
30 // a primitive leak checker.
31
32 #include <stdio.h>
33 #include <stdlib.h>
34
35 #include "gtest/gtest.h"
36 using ::testing::EmptyTestEventListener;
37 using ::testing::InitGoogleTest;
38 using ::testing::Test;
39 using ::testing::TestEventListeners;
40 using ::testing::TestInfo;
41 using ::testing::UnitTest;
42
43 namespace {
44 // We will track memory used by this class.
45 class Water {
46 public:
47 // Normal Water declarations go here.
48
49 // operator new and operator delete help us control water allocation.
operator new(size_t allocation_size)50 void* operator new(size_t allocation_size) {
51 allocated_++;
52 return malloc(allocation_size);
53 }
54
operator delete(void * block,size_t)55 void operator delete(void* block, size_t /* allocation_size */) {
56 allocated_--;
57 free(block);
58 }
59
allocated()60 static int allocated() { return allocated_; }
61
62 private:
63 static int allocated_;
64 };
65
66 int Water::allocated_ = 0;
67
68 // This event listener monitors how many Water objects are created and
69 // destroyed by each test, and reports a failure if a test leaks some Water
70 // objects. It does this by comparing the number of live Water objects at
71 // the beginning of a test and at the end of a test.
72 class LeakChecker : public EmptyTestEventListener {
73 private:
74 // Called before a test starts.
OnTestStart(const TestInfo &)75 void OnTestStart(const TestInfo& /* test_info */) override {
76 initially_allocated_ = Water::allocated();
77 }
78
79 // Called after a test ends.
OnTestEnd(const TestInfo &)80 void OnTestEnd(const TestInfo& /* test_info */) override {
81 int difference = Water::allocated() - initially_allocated_;
82
83 // You can generate a failure in any event handler except
84 // OnTestPartResult. Just use an appropriate Google Test assertion to do
85 // it.
86 EXPECT_LE(difference, 0) << "Leaked " << difference << " unit(s) of Water!";
87 }
88
89 int initially_allocated_;
90 };
91
TEST(ListenersTest,DoesNotLeak)92 TEST(ListenersTest, DoesNotLeak) {
93 Water* water = new Water;
94 delete water;
95 }
96
97 // This should fail when the --check_for_leaks command line flag is
98 // specified.
TEST(ListenersTest,LeaksWater)99 TEST(ListenersTest, LeaksWater) {
100 Water* water = new Water;
101 EXPECT_TRUE(water != nullptr);
102 }
103 } // namespace
104
main(int argc,char ** argv)105 int main(int argc, char** argv) {
106 InitGoogleTest(&argc, argv);
107
108 bool check_for_leaks = false;
109 if (argc > 1 && strcmp(argv[1], "--check_for_leaks") == 0)
110 check_for_leaks = true;
111 else
112 printf("%s\n",
113 "Run this program with --check_for_leaks to enable "
114 "custom leak checking in the tests.");
115
116 // If we are given the --check_for_leaks command line flag, installs the
117 // leak checker.
118 if (check_for_leaks) {
119 TestEventListeners& listeners = UnitTest::GetInstance()->listeners();
120
121 // Adds the leak checker to the end of the test event listener list,
122 // after the default text output printer and the default XML report
123 // generator.
124 //
125 // The order is important - it ensures that failures generated in the
126 // leak checker's OnTestEnd() method are processed by the text and XML
127 // printers *before* their OnTestEnd() methods are called, such that
128 // they are attributed to the right test. Remember that a listener
129 // receives an OnXyzStart event *after* listeners preceding it in the
130 // list received that event, and receives an OnXyzEnd event *before*
131 // listeners preceding it.
132 //
133 // We don't need to worry about deleting the new listener later, as
134 // Google Test will do it.
135 listeners.Append(new LeakChecker);
136 }
137 return RUN_ALL_TESTS();
138 }
139