Gtest源码剖析:1.实现一个超级简单的测试框架xtest

下面的代码模仿gtest实现，主要说明了以下两点:

1. ASSERT_* 和 EXPECT_*系列断言的原理和作用.
2. gtest是怎样通过宏自动注册测试代码让其自动运行的.

#include <iostream>
#include <string>
#include <memory>
#include <vector>


#define ASSERT_EQ(a,b) if((a) != (b)) 
    { 
        std::cout<<"[     FAIL ] "<<#a<<" not equal "<<#b<<std::endl; 
        return; 
    } else { 
        std::cout<<"[       OK ] "<<std::endl; 
    }

#define ASSERT_NE(a,b) if((a) == (b)) 
    { 
        std::cout<<"[     FAIL ] "<<#a<<" not equal "<<#b<<std::endl; 
        return; 
    } else { 
        std::cout<<"[       OK ] "<<std::endl; 
    }

#define EXPECT_EQ(a,b) if((a) != (b)) 
    { 
        std::cout<<"[     FAIL ] "<<#a<<" not equal "<<#b<<std::endl; 
    } else { 
        std::cout<<"[       OK ] "<<std::endl; 
    }

#define EXPECT_NE(a,b) if((a) == (b)) 
    { 
        std::cout<<"[     FAIL ] "<<#a<<" not equal "<<#b<<std::endl; 
    } else { 
        std::cout<<"[       OK ] "<<std::endl; 
    }

#define MAKE_CLASS_NAME(test_case_name, test_name)  MAKI_CLASS_NAME_I(test_case_name, test_name)
#define MAKI_CLASS_NAME_I(test_case_name, test_name) XTest_##test_case_name##_##test_name##_Test
#define XTEST_TEST(test_case_name,test_name) class MAKE_CLASS_NAME(test_case_name, test_name): 
    public ::xtest::Test { 
    public: 
        MAKE_CLASS_NAME(test_case_name, test_name)(): ::xtest::Test(#test_case_name, #test_name) 
        { 
            ::xtest::UnitTest::regist(std::shared_ptr<::xtest::Test>(this)); 
        } 
        virtual void testBody(); 
        static MAKE_CLASS_NAME(test_case_name, test_name) * instance; 
}; 
MAKE_CLASS_NAME(test_case_name, test_name) * MAKE_CLASS_NAME(test_case_name, test_name) ::instance 
    = new MAKE_CLASS_NAME(test_case_name, test_name) ();
void MAKE_CLASS_NAME(test_case_name, test_name)::testBody()

#define TEST(test_case_name, test_name) XTEST_TEST(test_case_name, test_name)


namespace xtest {

    class Test{
        friend class UnitTest;
    public:
        Test(const std::string &n1, const std::string& n2):test_case_name(n1), test_name(n2){
        }
        virtual void testBody() = 0;
        std::string test_case_name;
        std::string test_name;
    private:
        Test(const Test&) = delete;
        Test& operator=(const Test&) = delete;
    };

    class UnitTest {
    public:
        static UnitTest* getInstance();
        void Run();
        static void regist(std::shared_ptr<Test> const& a);
    private:
        static UnitTest* instance;
        std::vector<std::shared_ptr<Test>> all_tests12;
    };
}

inline void RUN_ALL_TESTS(){
    xtest::UnitTest::getInstance()->Run();
}

#include "xtest.h"
namespace xtest{

    UnitTest* UnitTest::instance = NULL;
    UnitTest* UnitTest::getInstance(){
        if(instance == NULL){
            instance = new UnitTest();
        }
        return instance;
    }
    void UnitTest::Run(){
        std::cout<<"[==========] Start XTest..."<<std::endl;
        for(auto i = begin(all_tests12); i!= end(all_tests12); ++i){
            std::cout<<"[ RUN      ] "<<(*i)->test_case_name<<"."<<(*i)->test_name<<std::endl;
            (*i)->testBody();
            std::cout<<std::endl;
        }
    }
    void UnitTest::regist(std::shared_ptr<Test>const& a){
        getInstance()->all_tests12.push_back(a);
    }
}

现在看看怎么用吧

#include "xtest.h"

TEST(t1,t2){
    ASSERT_EQ(1,1);
    ASSERT_EQ(1,2);
    ASSERT_EQ(2,3);
}
TEST(t3,t4){
    EXPECT_EQ(1,1);
    EXPECT_EQ(1,2);
    EXPECT_EQ(2,3);
}
int main(int argc, char* argv[]) {

    RUN_ALL_TESTS();
    return 0;
}

输出结果：

[==========] Start XTest...
[ RUN      ] t1.t2
[       OK ]
[     FAIL ] 1 not equal 2

[ RUN      ] t3.t4
[       OK ]
[     FAIL ] 1 not equal 2
[     FAIL ] 2 not equal 3