单元测试之CppTest测试框架

1 背景

前面文章CppTest实战演示中讲述如何使用CppTest库。其主函数如下：

int main(int argc, char *argv[])
{
    Test::Suite mainSuite;
    Test::TextOutput output(Test::TextOutput::Verbose);

    mainSuite.add(std::unique_ptr<Test::Suite>(new SeesionSuite));
    mainSuite.run(output, true);

    return 0;
}

以上代码有一点不好，就是每增加一个测试Suite就需要在main函数中调用mainSuite.add增加用例。有没有办法测试Suite自动添加，不需要修改main函数。下面讲述的测试框架可以解决这个问题。

2 设计

首先设计类TestApp，该类是单例模式，可以添加测试Suite,其次AutoAddSuite是一模板类在其构造函数中自动添加测试Suite.
其类图如下：

类定义如下：

class TestApp
{
    Test::Suite mainSuite_;
    TestApp();
public:
    static TestApp& Instance();

    void  addSuite(Test::Suite * suite);
    int run(int argc, char *argv[]);
};
#define theTestApp TestApp::Instance()

template<typename Suite>
class AutoAddSuite
{
    Suite* suite;
public:
    AutoAddSuite()
    : suite(new Suite())
    { 
        theTestApp.addSuite(suite);
    }
};
#define ADD_SUITE(Type) AutoAddSuite<Type>  add##Type

说明:

TestApp类型是单例类，提高增加Suite接口和run接口
AutoAddSuite是一个自动添加Suite的模板类型
宏ADD_SUITE定义了AutoAddSuite对象，用于自动添加。

3 实现

#include "testapp.h"

#include <iostream>
#include <cstring>
#include <cstdio>

namespace
{
void usage()
{
    std::cout << "usage: test [MODE]\n"
         << "where MODE may be one of:\n"
         << "  --compiler\n"
         << "  --html\n"
         << "  --text-terse (default)\n"
         << "  --text-verbose\n";
    exit(0);
}

std::unique_ptr<Test::Output> cmdline(int argc, char* argv[])
{
    if (argc > 2)
        usage(); // will not return

    Test::Output* output = 0;

    if (argc == 1)
        output = new Test::TextOutput(Test::TextOutput::Verbose);
    else
    {
        const char* arg = argv[1];
        if (strcmp(arg, "--compiler") == 0)
            output = new Test::CompilerOutput;
        else if (strcmp(arg, "--html") == 0)
            output =  new Test::HtmlOutput;
        else if (strcmp(arg, "--text-terse") == 0)
            output = new Test::TextOutput(Test::TextOutput::Terse);
        else if (strcmp(arg, "--text-verbose") == 0)
            output = new Test::TextOutput(Test::TextOutput::Verbose);
        else
        {
            std::cout << "invalid commandline argument: " << arg << std::endl;
            usage(); // will not return
        }
    }

    return std::unique_ptr<Test::Output>(output);
}
}

TestApp & TestApp::Instance()
{
    static TestApp theApp;
    return theApp;
}

TestApp::TestApp()
{}

void TestApp::addSuite(Test::Suite * suite)
{
    mainSuite_.add(std::unique_ptr<Test::Suite>(suite));
}

int TestApp::run(int argc, char *argv[])
{
    try
    {
        std::unique_ptr<Test::Output> output(cmdline(argc, argv));
        mainSuite_.run(*output, true);

        Test::HtmlOutput* const html = dynamic_cast<Test::HtmlOutput*>(output.get());
        if (html)
            html->generate(std::cout, true, argv[0]);
    }
    catch (...)
    {
        std::cout << "unexpected exception encountered\n";
        return EXIT_FAILURE;
    }
    return EXIT_SUCCESS;
}

说明:

Instance 返回一个单例引用
addSuite 增加Suite到mainSuite_
run
- 首先根据命令行返回Test::Output
- 然后调用mainSuite_运行测试用例
- 最后如果类型是Output是Test::HtmlOutput类型，则将结果输出到标准输出std::cout.

4 使用

4.1 主函数

#include "testapp.h"

int main(int argc, char *argv[])
{
    try
    {
        theTestApp.run(argc, argv);
    }
    catch(const std::exception& e)
    {
        std::cerr << e.what() << '\n';
    }
    return 0;
}

主函数很简单，不再详述。

4.2 测试用例

这里使用C++标准库中std::mutex作为测试示例.

4.2.1 定义

#ifndef MUTEX_TEST_H
#define MUTEX_TEST_H
#include <cpptest/cpptest.h>

class MutexSuite : public Test::Suite
{
public:
    MutexSuite()
    {
        TEST_ADD(MutexSuite::construct)
        TEST_ADD(MutexSuite::lock)
        TEST_ADD(MutexSuite::try_lock)
        TEST_ADD(MutexSuite::unlock)
    }

    void construct();
    void lock();
    void try_lock();
    void unlock();
};
#endif

说明：

cpptest库标准使用，不再详述。

4.2.2 实现

#include "mutex_test.h"
#include "testapp.h"

#include <thread>
#include <mutex>

ADD_SUITE(MutexSuite);

void addCount(std::mutex & mutex, int & count)
{
    mutex.lock();
    count++;
    mutex.unlock();
}

void MutexSuite::construct()
{
    std::mutex muxtex;
    int count = 0;
    std::thread threads[10];
    for(int i = 0; i < 10; i++)
        threads[i] = std::thread(addCount, std::ref(muxtex), std::ref(count));
    for(auto &thread : threads)
        thread.join();
    TEST_ASSERT_EQUALS(10, count)   
}

void MutexSuite::lock()
{
    std::mutex muxtex;
    int count = 10;
    std::thread threads[10];
    for(int i = 0; i < 10; i++)
        threads[i] = std::thread(addCount, std::ref(muxtex), std::ref(count));
    for(auto &thread : threads)
        thread.join();
    TEST_ASSERT_EQUALS(20, count)   
}

struct Function
{
    volatile int counter = 0;
    void add_10k_count(std::mutex & muxtex)
    {
        for(int i = 0; i < 10000; i++)
        {
            if(muxtex.try_lock())
            {
                ++counter;
                muxtex.unlock();
            }
        }
    }
};

void MutexSuite::try_lock()
{
    std::mutex muxtex;
    Function function;
    std::thread threads[10];
    for(int i = 0; i < 10; i++)
        threads[i] = std::thread(&Function::add_10k_count, std::ref(function), std::ref(muxtex));
    for(auto &thread : threads)
        thread.join();
    TEST_ASSERT_EQUALS(true, function.counter < (10 * 10000))
    std::cerr << "function.counter: " << function.counter << std::endl;
}

void MutexSuite::unlock()
{
    std::mutex muxtex;
    int count = 20;
    std::thread threads[10];
    for(int i = 0; i < 10; i++)
        threads[i] = std::thread(addCount, std::ref(muxtex), std::ref(count));
    for(auto &thread : threads)
        thread.join();
    TEST_ASSERT_EQUALS(30, count)   
}