Google test的使用
Google test是一种比较方便的C++测试框架，它能够帮助我们比较方便的进行测试代码的编写，以及输出尽可能详细的失败信息。能够大大缩短我们测试代码的编写效率，而且该框架的使用方法也比较简单，能够降低我们学习新框架的负担。
1. googletest的编译安装
1） 安装cmake
# yum install cmake # cmake --version cmake version 2.8.12.2
2) 编译并安装gtest
执行如下命令下载、编译并安装googletest:
# git clone https://github.com/google/googletest.git # ls appveyor.yml BUILD.bazel ci CMakeLists.txt CONTRIBUTING.md googlemock googletest library.json LICENSE platformio.ini README.md WORKSPACE # mkdir mybuild && cd mybuild # cmake .. -- The C compiler identification is GNU 4.8.5 -- The CXX compiler identification is GNU 4.8.5 -- Check for working C compiler: /usr/bin/cc -- Check for working C compiler: /usr/bin/cc -- works -- Detecting C compiler ABI info -- Detecting C compiler ABI info - done -- Check for working CXX compiler: /usr/bin/c++ -- Check for working CXX compiler: /usr/bin/c++ -- works -- Detecting CXX compiler ABI info -- Detecting CXX compiler ABI info - done -- Found PythonInterp: /usr/bin/python (found version "2.7.5") -- Looking for include file pthread.h -- Looking for include file pthread.h - found -- Looking for pthread_create -- Looking for pthread_create - not found -- Looking for pthread_create in pthreads -- Looking for pthread_create in pthreads - not found -- Looking for pthread_create in pthread -- Looking for pthread_create in pthread - found -- Found Threads: TRUE -- Configuring done -- Generating done -- Build files have been written to: /root/googletest/inst/googletest/mybuild # ls bin CMakeCache.txt CMakeFiles cmake_install.cmake CTestTestfile.cmake googlemock googletest lib Makefile
执行完上面的命令后，可以看到生成了相应的编译脚本，接着再执行如下命令完成编译与安装：
# make # make install [ 25%] Built target gtest [ 50%] Built target gmock [ 75%] Built target gmock_main [100%] Built target gtest_main Install the project... -- Install configuration: "" -- Installing: /usr/local/include -- Installing: /usr/local/include/gmock -- Installing: /usr/local/include/gmock/gmock-actions.h -- Installing: /usr/local/include/gmock/gmock-cardinalities.h -- Installing: /usr/local/include/gmock/gmock-function-mocker.h -- Installing: /usr/local/include/gmock/gmock-generated-actions.h -- Installing: /usr/local/include/gmock/gmock-generated-actions.h.pump -- Installing: /usr/local/include/gmock/gmock-generated-function-mockers.h -- Installing: /usr/local/include/gmock/gmock-generated-function-mockers.h.pump -- Installing: /usr/local/include/gmock/gmock-generated-matchers.h -- Installing: /usr/local/include/gmock/gmock-generated-matchers.h.pump -- Installing: /usr/local/include/gmock/gmock-matchers.h -- Installing: /usr/local/include/gmock/gmock-more-actions.h -- Installing: /usr/local/include/gmock/gmock-more-matchers.h -- Installing: /usr/local/include/gmock/gmock-nice-strict.h -- Installing: /usr/local/include/gmock/gmock-spec-builders.h -- Installing: /usr/local/include/gmock/gmock.h -- Installing: /usr/local/include/gmock/internal -- Installing: /usr/local/include/gmock/internal/custom -- Installing: /usr/local/include/gmock/internal/custom/README.md -- Installing: /usr/local/include/gmock/internal/custom/gmock-generated-actions.h -- Installing: /usr/local/include/gmock/internal/custom/gmock-generated-actions.h.pump -- Installing: /usr/local/include/gmock/internal/custom/gmock-matchers.h -- Installing: /usr/local/include/gmock/internal/custom/gmock-port.h -- Installing: /usr/local/include/gmock/internal/gmock-internal-utils.h -- Installing: /usr/local/include/gmock/internal/gmock-port.h -- Installing: /usr/local/include/gmock/internal/gmock-pp.h -- Installing: /usr/local/lib64/libgmock.a -- Installing: /usr/local/lib64/libgmock_main.a -- Installing: /usr/local/lib64/pkgconfig/gmock.pc -- Installing: /usr/local/lib64/pkgconfig/gmock_main.pc -- Installing: /usr/local/lib64/cmake/GTest/GTestTargets.cmake -- Installing: /usr/local/lib64/cmake/GTest/GTestTargets-noconfig.cmake -- Installing: /usr/local/lib64/cmake/GTest/GTestConfigVersion.cmake -- Installing: /usr/local/lib64/cmake/GTest/GTestConfig.cmake -- Installing: /usr/local/include -- Installing: /usr/local/include/gtest -- Installing: /usr/local/include/gtest/gtest-death-test.h -- Installing: /usr/local/include/gtest/gtest-matchers.h -- Installing: /usr/local/include/gtest/gtest-message.h -- Installing: /usr/local/include/gtest/gtest-param-test.h -- Installing: /usr/local/include/gtest/gtest-printers.h -- Installing: /usr/local/include/gtest/gtest-spi.h -- Installing: /usr/local/include/gtest/gtest-test-part.h -- Installing: /usr/local/include/gtest/gtest-typed-test.h -- Installing: /usr/local/include/gtest/gtest.h -- Installing: /usr/local/include/gtest/gtest_pred_impl.h -- Installing: /usr/local/include/gtest/gtest_prod.h -- Installing: /usr/local/include/gtest/internal -- Installing: /usr/local/include/gtest/internal/custom -- Installing: /usr/local/include/gtest/internal/custom/README.md -- Installing: /usr/local/include/gtest/internal/custom/gtest-port.h -- Installing: /usr/local/include/gtest/internal/custom/gtest-printers.h -- Installing: /usr/local/include/gtest/internal/custom/gtest.h -- Installing: /usr/local/include/gtest/internal/gtest-death-test-internal.h -- Installing: /usr/local/include/gtest/internal/gtest-filepath.h -- Installing: /usr/local/include/gtest/internal/gtest-internal.h -- Installing: /usr/local/include/gtest/internal/gtest-param-util.h -- Installing: /usr/local/include/gtest/internal/gtest-port-arch.h -- Installing: /usr/local/include/gtest/internal/gtest-port.h -- Installing: /usr/local/include/gtest/internal/gtest-string.h -- Installing: /usr/local/include/gtest/internal/gtest-type-util.h -- Installing: /usr/local/include/gtest/internal/gtest-type-util.h.pump -- Installing: /usr/local/lib64/libgtest.a -- Installing: /usr/local/lib64/libgtest_main.a -- Installing: /usr/local/lib64/pkgconfig/gtest.pc -- Installing: /usr/local/lib64/pkgconfig/gtest_main.pc
之后将/usr/local/lib64/pkgconfig添加到PKG_CONFIG_PATH中：
# vi /etc/profile export PKG_CONFIG_PATH=$PKG_CONFIG_PATH:/usr/local/lib/pkgconfig/:/usr/local/lib64/pkgconfig/ # source /etc/profile # echo $PKG_CONFIG_PATH :/usr/local/lib/pkgconfig/:/usr/local/lib64/pkgconfig/
2. 测试google test
下面我们编写一个Hello Google Test来进行测试（hello_test.cpp)：
#include <gtest/gtest.h>
#include <iostream>
//待测函数
int func(int a){
return a + 1;
}
//单元测试
TEST(FunTest, HandlesZeroInput){
EXPECT_EQ(1, func(0));
}
int main(int argc, char *argv[])
{
::testing::InitGoogleTest(&argc, argv);
return RUN_ALL_TESTS();
}执行如下命令进行编译：
# gcc -o hello_test hello_test.cpp -lstdc++ -std=c++11 `pkg-config --cflags --libs gtest` # ./hello_test [==========] Running 1 test from 1 test suite. [----------] Global test environment set-up. [----------] 1 test from FunTest [ RUN ] FunTest.HandlesZeroInput [ OK ] FunTest.HandlesZeroInput (0 ms) [----------] 1 test from FunTest (0 ms total) [----------] Global test environment tear-down [==========] 1 test from 1 test suite ran. (0 ms total) [ PASSED ] 1 test.
上面可以看到程序运行成功。
3. gtest运行原理
关于gtest的运行原理，我们先来googletest源码中TEST宏定义的实现：
// Defines a test.
//
// The first parameter is the name of the test suite, and the second
// parameter is the name of the test within the test suite.
//
// The convention is to end the test suite name with "Test". For
// example, a test suite for the Foo class can be named FooTest.
//
// Test code should appear between braces after an invocation of
// this macro. Example:
//
// TEST(FooTest, InitializesCorrectly) {
// Foo foo;
// EXPECT_TRUE(foo.StatusIsOK());
// }
// Note that we call GetTestTypeId() instead of GetTypeId<
// ::testing::Test>() here to get the type ID of testing::Test. This
// is to work around a suspected linker bug when using Google Test as
// a framework on Mac OS X. The bug causes GetTypeId<
// ::testing::Test>() to return different values depending on whether
// the call is from the Google Test framework itself or from user test
// code. GetTestTypeId() is guaranteed to always return the same
// value, as it always calls GetTypeId<>() from the Google Test
// framework.
#define GTEST_TEST(test_suite_name, test_name) \
GTEST_TEST_(test_suite_name, test_name, ::testing::Test, \
::testing::internal::GetTestTypeId())
// Define this macro to 1 to omit the definition of TEST(), which
// is a generic name and clashes with some other libraries.
#if !GTEST_DONT_DEFINE_TEST
#define TEST(test_suite_name, test_name) GTEST_TEST(test_suite_name, test_name)
#endif
// Defines a test that uses a test fixture.
//
// The first parameter is the name of the test fixture class, which
// also doubles as the test suite name. The second parameter is the
// name of the test within the test suite.
//
// A test fixture class must be declared earlier. The user should put
// the test code between braces after using this macro. Example:
//
// class FooTest : public testing::Test {
// protected:
// void SetUp() override { b_.AddElement(3); }
//
// Foo a_;
// Foo b_;
// };
//
// TEST_F(FooTest, InitializesCorrectly) {
// EXPECT_TRUE(a_.StatusIsOK());
// }
//
// TEST_F(FooTest, ReturnsElementCountCorrectly) {
// EXPECT_EQ(a_.size(), 0);
// EXPECT_EQ(b_.size(), 1);
// }
//
// GOOGLETEST_CM0011 DO NOT DELETE
#define TEST_F(test_fixture, test_name)\
GTEST_TEST_(test_fixture, test_name, test_fixture, \
::testing::internal::GetTypeId<test_fixture>())TEST是一个宏定义，而GTEST_TEST_也是一个宏，其会根据test_fixture以及test_name字符串拼接出一个class name，然后会采用该class生成相应的对象登记到google测试框架中。从而在调用RUN_ALL_TESTS()时就会一个个的执行相应的测试用例。例如:
TEST_F(FooTest, InitializesCorrectly) {
EXPECT_TRUE(a_.StatusIsOK());
}
//展开后会变成：
class FooTest_InitializesCorrectly_Test : public FooTest{
public:
FooTest_InitializesCorrectly_Test(FooTest, InitializesCorrectly){}
private: \
void TestBody() override;
static ::testing::TestInfo* const test_info_ GTEST_ATTRIBUTE_UNUSED_;
GTEST_DISALLOW_COPY_AND_ASSIGN_(GTEST_TEST_CLASS_NAME_(test_suite_name,test_name));
};
//然后再构造FooTest_InitializesCorrectly_Test对象，然后调用TestBody()方法。其中TestBody()方法其实就是通过宏拼凑出一个类似
//如下的函数
void FooTest_InitializesCorrectly_Test::TestBody(){
EXPECT_TRUE(a_.StatusIsOK());
}因为上面每个拼接生成的类都会继承自testing::Test，因此这里提供了另外一个宏定义TEST_F允许我们对testing::Testing做一些相应的修改，即我们可以通过继承testing::Test来对相应的成员函数进行重载，从而满足一些特定的需求。
4. 断言/宏测试
Google Test采用一系列的断言(assert)来进行代码测试，这些宏有点类似于函数调用。当断言失败时，Google Test将会打印出assertion时的源文件和出错行的位置，以及附加的失败信息，用户可以直接通过<<在这些断言宏后面跟上自己希望在断言命中时的输出信息。
测试宏可以分为两大类： ASSERT_*和EXPECT_*，这些成对的断言功能相同，但效果不同。其中ASSERT_*将会在失败时产生致命错误并中止当前调用它的函数的执行。EXPECT_*版本的会生成非致命错误，不会终止当前函数，而是继续执行当前函数。通常情况，应该首选使用EXPECT_*，因为ASSERT_*在报告完错误后不会进行清理工作，可能导致内存泄露问题。
- 基本断言
Fatal assertion Nonfatal assertion verifies
------------------------------------------------------------------------------------------------------
ASSERT_TRUE(condition) EXPECT_TRUE(condition) condition is true
ASSERT_FALSE(condition) EXPECT_FALSE(condition) condition is false- 二值比较
Fatal assertion Nonfatal assertion verifies
------------------------------------------------------------------------------------------------------
ASSERT_EQ(val1, val2) EXPECT_EQ(val1,val2) val1 == val2
ASSERT_NE(val1, val2) EXPECT_NE(val1,val2) val1 != val2
ASSERT_LT(val1, val2) EXPECT_LT(val1, val2) val1 < val2
ASSERT_LE(val1, val2) EXPECT_LE(val1, val2) val1 <= val2
ASSERT_GT(val1, val2) EXPECT_GT(val1, val2) val1 > val2
ASSERT_GE(val1, val2) EXPECT_GE(val1, val2) val1 >= val2- 字符串比较
Fatal assertion Nonfatal assertion verifies
-------------------------------------------------------------------------------------------------------------------------
ASSERT_STREQ(str1, str2) EXPECT_STREQ(str1, str2) the two C strings have the same content
ASSERT_STRNE(str1, str2) EXPECT_STRNE(str1, str2) the two C strings have different content
ASSERT_STRCASEEQ(str1, str2) EXPECT_STRCASEEQ(str1, str2) the two C strings have the same content, ignoring case
ASSERT_STRCASENE(str1, str2) EXPECT_STRCASENE(str1, str2) the two C strings have different content, ignoring case5. 事件机制
1) 全局事件
要实现全局事件，必须写一个类，继承testing::Environment类，实现里面的SetUp()和TearDown()方法。
-
Setup()方法在所有案例执行前执行
-
TearDown()方法在所有案例执行后执行
还需要告诉gtest添加这个全局事件，我们需要在main函数中通过testing::AddGlobalTestEnvironment()方法将事件挂进来，也就是说，我们可以写很多个这样的类，然后把它们的事件都挂上去。
2） TestSuit事件
我们需要写一个类，继承testing::Test，然后实现两个静态方法：
-
SetupTestCase()该方法在第一个TestCase之前执行
-
TearDownTestCase()该方法在最后一个TestCase之后执行
在编写测试案例时，我们需要使用TEST_F这个宏，第一个参数必须是我们上面类的名字，代表一个TestSuit。
3） TestCase事件
TestCase事件是挂在每个案例执行前后的，实现方式和上面的几乎一样，不过需要实现的是Setup()方法和TearDown()方法：
-
Setup()方法在每个TestCase之前执行
-
TearDown()方法在每个TestCase之后执行
以下案例说明上述三个事件的使用：
#include<gtest/gtest.h>
#include<map>
#include<iostream>
using namespace std;
class Student{
public:
Student(){
age=0;
}
Student(int a){
age=a;
}
void print(){
cout<<"*********** "<<age<<" **********"<<endl;;
}
private:
int age;
};
class FooEnvironment : public testing::Environment{
public:
virtual void SetUp()
{
std::cout << "Foo FooEnvironment SetUP" << std::endl;
}
virtual void TearDown()
{
std::cout << "Foo FooEnvironment TearDown" << std::endl;
}
};
static Student *s = NULL;
//在第一个test之前，最后一个test之后调用SetUpTestCase()和TearDownTestCase()
class TestMap:public testing::Test
{
public:
static void SetUpTestCase()
{
cout<<"SetUpTestCase()"<<endl;
s=new Student(23);
}
static void TearDownTestCase()
{
delete s;
cout<<"TearDownTestCase()"<<endl;
}
void SetUp()
{
cout<<"SetUp() is running"<<endl;
}
void TearDown()
{
cout<<"TearDown()"<<endl;
}
};
TEST_F(TestMap, test1){
cout<<"this is test1"<<endl;
s->print();
cout<<"end test1"<<endl;
}
TEST_F(TestMap, test2){
cout<<"this is test2"<<endl;
s->print();
cout<<"end test2"<<endl;
}
int main(int argc, char *argv[]){
testing::AddGlobalTestEnvironment(new FooEnvironment);
testing::InitGoogleTest(&argc, argv);
return RUN_ALL_TESTS();
}编译运行：
# gcc -o test test.cpp -lstdc++ -std=c++11 `pkg-config --cflags --libs gtest` # ./test [==========] Running 2 tests from 1 test suite. [----------] Global test environment set-up. Foo FooEnvironment SetUP [----------] 2 tests from TestMap SetUpTestCase() [ RUN ] TestMap.test1 SetUp() is running this is test1 *********** 23 ********** end test1 TearDown() [ OK ] TestMap.test1 (0 ms) [ RUN ] TestMap.test2 SetUp() is running this is test2 *********** 23 ********** end test2 TearDown() [ OK ] TestMap.test2 (1 ms) TearDownTestCase() [----------] 2 tests from TestMap (1 ms total) [----------] Global test environment tear-down Foo FooEnvironment TearDown [==========] 2 tests from 1 test suite ran. (1 ms total) [ PASSED ] 2 tests.
6. 参数化
当考虑多次要为被测函数传入不同的值的情况时，可以按下面的方法去测试。必须添加一个类，继承自testing::TestWithParam
#include<gtest/gtest.h>
// Returns true iff n is a prime number.
bool IsPrime(int n)
{
// Trivial case 1: small numbers
if (n <= 1) return false;
// Trivial case 2: even numbers
if (n % 2 == 0) return n == 2;
// Now, we have that n is odd and n >= 3.
// Try to divide n by every odd number i, starting from 3
for (int i = 3; ; i += 2) {
// We only have to try i up to the squre root of n
if (i > n/i) break;
// Now, we have i <= n/i < n.
// If n is divisible by i, n is not prime.
if (n % i == 0) return false;
}
// n has no integer factor in the range (1, n), and thus is prime.
return true;
}
bool isEven(int n)
{
return n % 2 == 0 ? true : false;
}
class MyParamTest : public::testing::TestWithParam<int>{};
TEST_P(MyParamTest, CheckPrimer)
{
int n = GetParam();
EXPECT_TRUE(IsPrime(n));
}
TEST_P(MyParamTest, CheckEven)
{
int n = GetParam();
EXPECT_TRUE(isEven(n));
}
//被测函数须传入多个相关的值
INSTANTIATE_TEST_CASE_P(NumberTest, MyParamTest, testing::Values(3, 5, 11, 23, 17));
int main(int argc, char **argv)
{
testing::InitGoogleTest(&argc, argv);
return RUN_ALL_TESTS();
}编译运行：
# gcc -o test test.cpp -lstdc++ -std=c++11 `pkg-config --cflags --libs gtest` # ./test [==========] Running 5 tests from 1 test suite. [----------] Global test environment set-up. [----------] 5 tests from TrueReturn/IsPrimeParamTest [ RUN ] TrueReturn/IsPrimeParamTest.HandleTrueReturn/0 [ OK ] TrueReturn/IsPrimeParamTest.HandleTrueReturn/0 (0 ms) [ RUN ] TrueReturn/IsPrimeParamTest.HandleTrueReturn/1 [ OK ] TrueReturn/IsPrimeParamTest.HandleTrueReturn/1 (0 ms) [ RUN ] TrueReturn/IsPrimeParamTest.HandleTrueReturn/2 [ OK ] TrueReturn/IsPrimeParamTest.HandleTrueReturn/2 (0 ms) [ RUN ] TrueReturn/IsPrimeParamTest.HandleTrueReturn/3 [ OK ] TrueReturn/IsPrimeParamTest.HandleTrueReturn/3 (0 ms) [ RUN ] TrueReturn/IsPrimeParamTest.HandleTrueReturn/4 [ OK ] TrueReturn/IsPrimeParamTest.HandleTrueReturn/4 (0 ms) [----------] 5 tests from TrueReturn/IsPrimeParamTest (0 ms total) [----------] Global test environment tear-down [==========] 5 tests from 1 test suite ran. (1 ms total) [ PASSED ] 5 tests.
[参看]
