CPPUTest 單元測試框架(針對 C 單元測試的使用說明)

CPPUTest 雖然名稱上看起來是 C++ 的單元測試框架, 其實它也是支持測試 C 代碼的.

本文主要介紹用CPPUTest來測試 C 代碼. (C++沒用過, 平時主要用的是C) C++相關的內容都省略了.

本文基於 debian v7.6 x86_64.

 

1. CPPUTest 安裝

現在各個Linux的發行版的源都有豐富的軟件資源, 而且安裝方便.

但是如果想要在第一時間使用最新版本的開源軟件, 還是得從源碼安裝.

 

debian系統為了追求穩定性, apt源中的軟件一般都比較舊. 所以本文中的例子是基於最新源碼的CPPUTest.

 

1.1 apt-get 安裝

$ sudo apt-get install cpputest

 

1.2 源碼安裝

1. 下載源碼, 官網: http://cpputest.github.io/

2. 編譯源碼

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

 

最后我沒有實際安裝， 而是直接使用編譯出的二進制。

 

2. CPPUTest 介紹

2.1 構造待測試代碼 (C語言)

/* 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\0");
    strcpy(pb, "hijklmn\0");
        
    printf ("Sample Start......\n");
    
    ret_void();
    printf ("ret_int: %d\n", ret_int(100, 10));
    printf ("ret_double: %.2f\n", ret_double(100.0, 10.0));
    printf ("ret_pchar: %s\n", 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\n", s->name, s->score);
    printf ("Sample End  ......\n");
    free(pa);
    free(pb);
    free(s->name);
    free(s);
    
    return 0;
}
#endif

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

/* 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 測試用例的組成, 寫法

CPPUTest 的測試用例非常簡單, 首先定義一個 TEST_GROUP, 然后定義屬於這個 TEST_GROUP 的 TEST.

需要注意的地方是:

1. 引用 CPPUTest 中的2個頭文件

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

 

2. 引用 C 頭文件時, 需要使用 extern "C" {}

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

 

下面的例子是測試 sample.c 中 ret_int 的代碼.

構造了一個測試成功, 一個測試失敗的例子

/* file: test.c */

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

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


/* 定義個 TEST_GROUP, 名稱為 sample */
TEST_GROUP(sample)
{};

/* 定義一個屬於 TEST_GROUP 的 TEST, 名稱為 ret_int_success */
TEST(sample, ret_int_success)
{
    int sum = ret_int(1, 2);
    CHECK_EQUAL(sum, 3);
}

/* 定義一個屬於 TEST_GROUP 的 TEST, 名稱為 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 測試用例結果判斷 ( fail, 各種assert等等)

測試完成后, 可以用 CPPUTest 提供的宏來判斷測試結果是否和預期一致.

CPPUTest 提供的用於判斷的宏如下: (上面的測試代碼就使用了 CHECK_EQUAL)

Assertion 宏	含義
CHECK(boolean condition)	condition==True則成功; 反之失敗
CHECK_TEXT(boolean condition, text)	condition==True則成功; 反之失敗, 並且失敗時輸出 text信息
CHECK_EQUAL(expected, actual)	expected==actual則成功; 反之失敗
CHECK_THROWS(expected_exception, expression)	拋出的異常 expected_exception==exception則成功; 反之失敗
STRCMP_EQUAL(expected, actual)	字符串 expected==actual則成功; 反之失敗
LONGS_EQUAL(expected, actual)	數字 expected==actual則成功; 反之失敗
BYTES_EQUAL(expected, actual)	數字 expected==actual則成功; 反之失敗 (數字是 8bit 寬)
POINTERS_EQUAL(expected, actual)	指針 expected==actual則成功; 反之失敗
DOUBLES_EQUAL(expected, actual, tolerance)	double型 expected和actual在誤差范圍內(tolerance)相等則成功; 反之失敗
FAIL(text)	總是失敗, 並輸出 text 信息

 

2.4 運行測試用例時的編譯選項配置 (主要是C語言相關的)

這一步是最關鍵的, 也就是編譯出單元測試文件. 下面是 makefile 的寫法, 關鍵位置加了注釋.

# makefile for sample cpputest

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

CC      := gcc
CFLAGS    := -g -Wall
CFLAGS  += -std=c99
CFLAGS  += -D CPPUTEST            # 編譯測試文件時, 忽略sample.c的main函數, sample.c的代碼中用了宏CPPUTEST

# CPPUTest 是C++寫的, 所以用 g++ 來編譯 測試文件
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)

# 追加的測試程序編譯
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

 

編譯測試文件

make test  <-- 會生成一個文件名為 test 可執行文件

編譯sample程序時, 需要把 "CFLAGS  += -D CPPUTEST" 這句注釋掉, 否則沒有main函數.

 

2.5 運行測試用例, 查看結果的方法

運行可執行文件 test 就可以實施測試.

$ ./test    <-- 默認執行, 沒有參數

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 執行結果加上顏色 (成功綠色, 失敗紅色)

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中顯示紅色

=================================================================================
$ ./test -v  <-- -v 顯示更為詳細的信息
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 指定測試執行的次數, 這里把測試重復執行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, 本例其實只有一個 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 指定執行其中一個 TEST, 名稱為 ret_int_success
.
OK (2 tests, 1 ran, 1 checks, 0 ignored, 1 filtered out, 0 ms)

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

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

 

2.6 補充: setup and teardown

上面 test.c 文件中 TEST_GROUP(sample) 中的代碼是空的, 其實 CPPUTest 中內置了 2 個調用 setup 和 teardown.

在 TEST_GROUP 中實現這2個函數之后, 每個屬於這個 TEST_GROUP 的 TEST 在執行之前都會調用 setup, 執行之后會調用 teardown.

修改 test.c 中的 TEST_GROUP 如下:

/* 定義個 TEST_GROUP, 名稱為 sample */
TEST_GROUP(sample)
{
    void setup()
    {
        printf ("測試開始......\n");
    }

    void teardown()
    {
        printf ("測試結束......\n");
    }
};

 

重新執行測試: (每個測試之前, 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)測試開始......

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

測試結束......
 - 0 ms
TEST(sample, ret_int_success)測試開始......
測試結束......
 - 0 ms

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

 

2.7 內存泄漏檢測插件

內存泄漏一直是C/C++代碼中令人頭疼的問題, 還好, CPPUTest 中提供了檢測內存泄漏的插件, 使用這個插件, 可使我們的代碼更加健壯.

 

使用內存檢測插件時, 測試代碼 和 待測代碼 在編譯時都要引用.

-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            # 編譯測試文件時, 忽略sample.c的main函數, sample.c的代碼中用了宏CPPUTEST

# CPPUTest 是C++寫的, 所以用 g++ 來編譯 測試文件
CPP     := g++
CPPFLAGS  := -g -Wall
CPPFLAGS  += -I$(CPPUTEST_HOME)/include

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

# 內存泄露檢測
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)

# 追加的測試程序編譯
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 函數, 構造一個內存泄漏的例子.

/* 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); /* 這里申請的內存, 最后沒有釋放 */
    strcpy(s->name, name2);

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

 

修改 test.c 追加一個測試 init_student 函數的測試用例

TEST(sample, init_student)
{
    struct Student *stu = NULL;
    stu = (struct Student*) malloc(sizeof(struct Student));
    char name[80] = {'t', 'e', 's', 't', '\0'};
    
    init_student(stu, name, 100);
    free(stu);
}

 

執行測試, 可以發現測試結果中提示 sample.c 72 行有內存泄漏風險,

這一行正是 init_student 函數中用 malloc 申請內存的那一行.

$ 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)測試開始......
測試結束......

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)