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() = ;
         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(,);
     ASSERT_EQ(,);
     ASSERT_EQ(,);
 }
 TEST(t3,t4){
     EXPECT_EQ(,);
     EXPECT_EQ(,);
     EXPECT_EQ(,);
 }
 int main(int argc, char* argv[]) {

     RUN_ALL_TESTS();
     return ;
 }

输出结果：

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

 [ RUN      ] t3.t4
 [       OK ]
 [     FAIL ]  not equal
 [     FAIL ]  not equal