CPPUTest 单元测试框架(针对 C 单元测试的使用说明)

CPPUTest 虽然名称上看起来是 C++ 的单元测试框架, 其实它也是支持测试 C 代码的.

本文主要介绍用CPPUTest来测试 C 代码. (C++没用过, 平时主要用的是C) C++相关的内容都省略了.

本文基于 debian v7.6 x86_64.

1. CPPUTest 安装

现在各个Linux的发行版的源都有丰富的软件资源, 而且安装方便.

但是如果想要在第一时间使用最新版本的开源软件, 还是得从源码安装.

debian系统为了追求稳定性, apt源中的软件一般都比较旧. 所以本文中的例子是基于最新源码的CPPUTest.

1.1 apt-get 安装

$ sudo apt-get install cpputest

1.2 源码安装

1. 下载源码, 官网: http://cpputest.github.io/

2. 编译源码

$ tar zxvf cpputest-3.6.tar.gz
$ cd cpputest-3.6/
$ ./configure
$ make

最后我没有实际安装， 而是直接使用编译出的二进制。

2. CPPUTest 介绍

2.1 构造待测试代码 (C语言)

/* file: sample.h */

#include <stdio.h>
#include <string.h>
#include <stdlib.h>

struct Student 
{
    char* name;
    int score;
};

void ret_void(void);
int ret_int(int, int);
double ret_double(double, double);
char* ret_pchar(char*, char*);

struct Student* init_student(struct Student* s, char* name, int score);

/* file: sample.c */

#include "sample.h"

#ifndef CPPUTEST
int main(int argc, char *argv[])
{
    char* pa;
    char* pb;
    pa = (char*) malloc(sizeof(char) * 80);
    pb = (char*) malloc(sizeof(char) * 20);

    strcpy(pa, "abcdefg");
    strcpy(pb, "hijklmn");
        
    printf ("Sample Start......
");
    
    ret_void();
    printf ("ret_int: %d
", ret_int(100, 10));
    printf ("ret_double: %.2f
", ret_double(100.0, 10.0));
    printf ("ret_pchar: %s
", ret_pchar(pa, pb));

    struct Student* s = (struct Student*) malloc(sizeof(struct Student));
    s->name = (char*) malloc(sizeof(char) * 80);
    
    init_student(s, "test cpputest", 100);
    printf ("init_Student: name=%s, score=%d
", s->name, s->score);
    printf ("Sample End  ......
");
    free(pa);
    free(pb);
    free(s->name);
    free(s);
    
    return 0;
}
#endif

void ret_void()
{
    printf ("Hello CPPUTest!
");
}

/* ia + ib */
int ret_int(int ia, int ib)
{
    return ia + ib;
}

/* da / db */
double ret_double(double da, double db)
{
    return da / db;
}

/* pa = pa + pb */
char* ret_pchar(char* pa, char* pb)
{
    return strcat(pa, pb);
}

/* s->name = name, s->score = score */
void init_student(struct Student* s, char* name, int score)
{
    strcpy(s->name, name);
    s->score = score;
}

2.2 测试用例的组成, 写法

CPPUTest 的测试用例非常简单, 首先定义一个 TEST_GROUP, 然后定义属于这个 TEST_GROUP 的 TEST.

需要注意的地方是:

1. 引用 CPPUTest 中的2个头文件

#include <CppUTest/CommandLineTestRunner.h>
#include <CppUTest/TestHarness.h>

2. 引用 C 头文件时, 需要使用 extern "C" {}

extern "C"
{
#include "sample.h"
}

下面的例子是测试 sample.c 中 ret_int 的代码.

构造了一个测试成功, 一个测试失败的例子

/* file: test.c */

#include <CppUTest/CommandLineTestRunner.h>
#include <CppUTest/TestHarness.h>

extern "C"
{
#include "sample.h"
}


/* 定义个 TEST_GROUP, 名称为 sample */
TEST_GROUP(sample)
{};

/* 定义一个属于 TEST_GROUP 的 TEST, 名称为 ret_int_success */
TEST(sample, ret_int_success)
{
    int sum = ret_int(1, 2);
    CHECK_EQUAL(sum, 3);
}

/* 定义一个属于 TEST_GROUP 的 TEST, 名称为 ret_int_failed */
TEST(sample, ret_int_failed)
{
    int sum = ret_int(1, 2);
    CHECK_EQUAL(sum, 4);
}

int main(int argc, char *argv[])
{
    CommandLineTestRunner::RunAllTests(argc, argv);
    return 0;
}

2.3 测试用例结果判断 ( fail, 各种assert等等)

测试完成后, 可以用 CPPUTest 提供的宏来判断测试结果是否和预期一致.

CPPUTest 提供的用于判断的宏如下: (上面的测试代码就使用了 CHECK_EQUAL)

Assertion 宏	含义
CHECK(boolean condition)	condition==True则成功; 反之失败
CHECK_TEXT(boolean condition, text)	condition==True则成功; 反之失败, 并且失败时输出 text信息
CHECK_EQUAL(expected, actual)	expected==actual则成功; 反之失败
CHECK_THROWS(expected_exception, expression)	抛出的异常 expected_exception==exception则成功; 反之失败
STRCMP_EQUAL(expected, actual)	字符串 expected==actual则成功; 反之失败
LONGS_EQUAL(expected, actual)	数字 expected==actual则成功; 反之失败
BYTES_EQUAL(expected, actual)	数字 expected==actual则成功; 反之失败 (数字是 8bit 宽)
POINTERS_EQUAL(expected, actual)	指针 expected==actual则成功; 反之失败
DOUBLES_EQUAL(expected, actual, tolerance)	double型 expected和actual在误差范围内(tolerance)相等则成功; 反之失败
FAIL(text)	总是失败, 并输出 text 信息

2.4 运行测试用例时的编译选项配置 (主要是C语言相关的)

这一步是最关键的, 也就是编译出单元测试文件. 下面是 makefile 的写法, 关键位置加了注释.

# makefile for sample cpputest

CPPUTEST_HOME = /home/wangyubin/Downloads/cpputest-3.6

CC      := gcc
CFLAGS    := -g -Wall
CFLAGS  += -std=c99
CFLAGS  += -D CPPUTEST            # 编译测试文件时, 忽略sample.c的main函数, sample.c的代码中用了宏CPPUTEST

# CPPUTest 是C++写的, 所以用 g++ 来编译 测试文件
CPP     := g++
CPPFLAGS  := -g -Wall
CPPFLAGS  += -I$(CPPUTEST_HOME)/include

LDFLAGS := -L$(CPPUTEST_HOME)/lib -lCppUTest


sample: sample.o

sample.o: sample.h sample.c
    $(CC) -c -o sample.o sample.c $(CFLAGS)

# 追加的测试程序编译
test: test.o sample.o
    $(CPP) -o $@ test.o sample.o $(LDFLAGS)

test.o: sample.h test.c
    $(CPP) -c -o test.o test.c $(CPPFLAGS)


.PHONY: clean
clean:
    @echo "clean..."
    rm -f test sample
    rm -f sample.o test.o

编译测试文件

make test  <-- 会生成一个文件名为 test 可执行文件

编译sample程序时, 需要把 "CFLAGS  += -D CPPUTEST" 这句注释掉, 否则没有main函数.

2.5 运行测试用例, 查看结果的方法

运行可执行文件 test 就可以实施测试.

$ ./test    <-- 默认执行, 没有参数

test.c:34: error: Failure in TEST(sample, ret_int_failed)
    expected <3>
    but was  <4>
    difference starts at position 0 at: <          4         >
                                                   ^

..
Errors (1 failures, 2 tests, 2 ran, 2 checks, 0 ignored, 0 filtered out, 1 ms)

=================================================================================
$ ./test -c   <-- -c 执行结果加上颜色 (成功绿色, 失败红色)

test.c:34: error: Failure in TEST(sample, ret_int_failed)
    expected <3>
    but was  <4>
    difference starts at position 0 at: <          4         >
                                                   ^

..
Errors (1 failures, 2 tests, 2 ran, 2 checks, 0 ignored, 0 filtered out, 1 ms) <-- bash中显示红色

=================================================================================
$ ./test -v  <-- -v 显示更为详细的信息
TEST(sample, ret_int_failed)
test.c:34: error: Failure in TEST(sample, ret_int_failed)
    expected <3>
    but was  <4>
    difference starts at position 0 at: <          4         >
                                                   ^

 - 1 ms
TEST(sample, ret_int_success) - 0 ms

Errors (1 failures, 2 tests, 2 ran, 2 checks, 0 ignored, 0 filtered out, 1 ms)

=================================================================================
$ ./test -r 2   <-- -r 指定测试执行的次数, 这里把测试重复执行2遍
Test run 1 of 2

test.c:34: error: Failure in TEST(sample, ret_int_failed)
    expected <3>
    but was  <4>
    difference starts at position 0 at: <          4         >
                                                   ^

..
Errors (1 failures, 2 tests, 2 ran, 2 checks, 0 ignored, 0 filtered out, 0 ms)

Test run 2 of 2

test.c:34: error: Failure in TEST(sample, ret_int_failed)
    expected <3>
    but was  <4>
    difference starts at position 0 at: <          4         >
                                                   ^

..
Errors (1 failures, 2 tests, 2 ran, 2 checks, 0 ignored, 0 filtered out, 1 ms)

=================================================================================
$ ./test -g sample    <-- -g 指定 TEST_GROUP, 本例其实只有一个 TEST_GROUP sample

test.c:34: error: Failure in TEST(sample, ret_int_failed)
    expected <3>
    but was  <4>
    difference starts at position 0 at: <          4         >
                                                   ^

..
Errors (1 failures, 2 tests, 2 ran, 2 checks, 0 ignored, 0 filtered out, 1 ms)

=================================================================================
$ ./test -n ret_int_success    <-- -s 指定执行其中一个 TEST, 名称为 ret_int_success
.
OK (2 tests, 1 ran, 1 checks, 0 ignored, 1 filtered out, 0 ms)

=================================================================================
$ ./test -v -n ret_int_success  <-- 参数也可以搭配使用
TEST(sample, ret_int_success) - 0 ms

OK (2 tests, 1 ran, 1 checks, 0 ignored, 1 filtered out, 0 ms)

2.6 补充: setup and teardown

上面 test.c 文件中 TEST_GROUP(sample) 中的代码是空的, 其实 CPPUTest 中内置了 2 个调用 setup 和 teardown.

在 TEST_GROUP 中实现这2个函数之后, 每个属于这个 TEST_GROUP 的 TEST 在执行之前都会调用 setup, 执行之后会调用 teardown.

修改 test.c 中的 TEST_GROUP 如下:

/* 定义个 TEST_GROUP, 名称为 sample */
TEST_GROUP(sample)
{
    void setup()
    {
        printf ("测试开始......
");
    }

    void teardown()
    {
        printf ("测试结束......
");
    }
};

重新执行测试: (每个测试之前, 之后都多了上面的打印信息)

$ make clean
clean...
rm -f test sample
rm -f sample.o test.o
$ make test
g++ -c -o test.o test.c -g -Wall -I/home/wangyubin/Downloads/cpputest-3.6/include
gcc -c -o sample.o sample.c -g -Wall -std=c99 -D CPPUTEST            
g++ -o test test.o sample.o -L/home/wangyubin/Downloads/cpputest-3.6/lib -lCppUTest
$ ./test -v
TEST(sample, ret_int_failed)测试开始......

test.c:44: error: Failure in TEST(sample, ret_int_failed)
    expected <3>
    but was  <4>
    difference starts at position 0 at: <          4         >
                                                   ^

测试结束......
 - 0 ms
TEST(sample, ret_int_success)测试开始......
测试结束......
 - 0 ms

Errors (1 failures, 2 tests, 2 ran, 2 checks, 0 ignored, 0 filtered out, 0 ms)

2.7 内存泄漏检测插件

内存泄漏一直是C/C++代码中令人头疼的问题, 还好, CPPUTest 中提供了检测内存泄漏的插件, 使用这个插件, 可使我们的代码更加健壮.

使用内存检测插件时, 测试代码 和 待测代码 在编译时都要引用.

-include $(CPPUTEST_HOME)/include/CppUTest/MemoryLeakDetectorMallocMacros.h

makefile 修改如下:

# makefile for sample cpputest

CPPUTEST_HOME = /home/wangyubin/Downloads/cpputest-3.6

CC      := gcc
CFLAGS    := -g -Wall
CFLAGS  += -std=c99
CFLAGS  += -D CPPUTEST            # 编译测试文件时, 忽略sample.c的main函数, sample.c的代码中用了宏CPPUTEST

# CPPUTest 是C++写的, 所以用 g++ 来编译 测试文件
CPP     := g++
CPPFLAGS  := -g -Wall
CPPFLAGS  += -I$(CPPUTEST_HOME)/include

LDFLAGS := -L$(CPPUTEST_HOME)/lib -lCppUTest

# 内存泄露检测
MEMFLAGS = -include $(CPPUTEST_HOME)/include/CppUTest/MemoryLeakDetectorMallocMacros.h

sample: sample.o

sample.o: sample.h sample.c
    $(CC) -c -o sample.o sample.c $(CFLAGS) $(MEMFLAGS)

# 追加的测试程序编译
test: test.o sample.o
    $(CPP) -o $@ test.o sample.o $(LDFLAGS)

test.o: sample.h test.c
    $(CPP) -c -o test.o test.c $(CPPFLAGS)  $(MEMFLAGS)


.PHONY: clean
clean:
    @echo "clean..."
    rm -f test sample
    rm -f sample.o test.o

修改 sample.c 中的 init_student 函数, 构造一个内存泄漏的例子.

/* s->name = name, s->score = score */
void init_student(struct Student* s, char* name, int score)
{
    char* name2 = NULL;
    name2 = (char*) malloc(sizeof(char) * 80); /* 这里申请的内存, 最后没有释放 */
    strcpy(s->name, name2);

    strcpy(s->name, name);
    s->score = score;
}

修改 test.c 追加一个测试 init_student 函数的测试用例

TEST(sample, init_student)
{
    struct Student *stu = NULL;
    stu = (struct Student*) malloc(sizeof(struct Student));
    char name[80] = {'t', 'e', 's', 't', ''};
    
    init_student(stu, name, 100);
    free(stu);
}

执行测试, 可以发现测试结果中提示 sample.c 72 行有内存泄漏风险,

这一行正是 init_student 函数中用 malloc 申请内存的那一行.

$ make clean
clean...
rm -f test sample
rm -f sample.o test.o
$ make test
g++ -c -o test.o test.c -g -Wall -I/home/wangyubin/Downloads/cpputest-3.6/include  -include /home/wangyubin/Downloads/cpputest-3.6/include/CppUTest/MemoryLeakDetectorMallocMacros.h
gcc -c -o sample.o sample.c -g -Wall -std=c99 -D CPPUTEST             -include /home/wangyubin/Downloads/cpputest-3.6/include/CppUTest/MemoryLeakDetectorMallocMacros.h
g++ -o test test.o sample.o -L/home/wangyubin/Downloads/cpputest-3.6/lib -lCppUTest
$ ./test -v -n init_student
TEST(sample, init_student)测试开始......
测试结束......

test.c:47: error: Failure in TEST(sample, init_student)
    Memory leak(s) found.
Alloc num (4) Leak size: 80 Allocated at: sample.c and line: 72. Type: "malloc"
     Memory: <0x120c5f0> Content: ""
Total number of leaks:  1
NOTE:
    Memory leak reports about malloc and free can be caused by allocating using the cpputest version of malloc,
    but deallocate using the standard free.
    If this is the case, check whether your malloc/free replacements are working (#define malloc cpputest_malloc etc).


 - 0 ms

Errors (1 failures, 3 tests, 1 ran, 0 checks, 0 ignored, 2 filtered out, 0 ms)