编写测试用例
一旦我们知道我们要测什么之后，我们就可以写测试用例了。我们能够执行所有的我们需要的操作：使用普通库函数，第三方库，win32api库函数，或简单使用c++内部操作
有时候，我们需要调用外部辅助文件或者数据库，比较外部文件和内部数据是否一致。
检测一个条件就使用
CPPUNIT_ASSERT(condition):如果为false就抛出异常
CPPUNIT_ASSERT_MESSAGE(message, condition): 如果为false就抛出制定的信息。
CPPUNIT_ASSERT_EQUAL(expected,current): 检测期望值
CPPUNIT_ASSERT_EQUAL_MESSAGE(message,expected,current): 当比较值不相等时候抛出的制定的信息。
CPPUNIT_ASSERT_DOUBLES_EQUAL(expected,current,delta): 带精度的比较
下面是测试loadTest的例子， //
// These are correct values stored in auxiliar file
//
#define AUX_FILENAME "ok_data.dat"
#define FILE_NUMBER 19
#define FILE_STRING "this is correct text stored in auxiliar file"
void DiskDataTestCase::loadTest()
{
// convert from relative to absolute path
TCHAR absoluteFilename[MAX_PATH];
DWORD size = MAX_PATH;
strcpy(absoluteFilename, AUX_FILENAME);
CPPUNIT_ASSERT( RelativeToAbsolutePath(absoluteFilename, &size) );
// executes action
CPPUNIT_ASSERT( fixture-＞load(absoluteFilename) );
// ...and check results with assertions
LPDATA loadedData = fixture-＞getData();
CPPUNIT_ASSERT(loadedData != NULL);
CPPUNIT_ASSERT_EQUAL(FILE_NUMBER, loadedData-＞number);
CPPUNIT_ASSERT( 0 == strcmp(FILE_STRING,
fixture-＞getData()-＞string) );
}
在这个case我们得到四个可能的错误： load method's return value
getData method's return value
number structure member's value
string structure member's value
第二个用例也是相似的。但是困难点，我们需要使用已知的数据来填充fixture，把它存在磁盘临时文件里，然后打开两个文件（新的和辅助文件），读并比较内容，两者如一致就正确 void DiskDataTestCase::storeTest()
{
DATA d;
DWORD tmpSize, auxSize;
BYTE *tmpBuff, *auxBuff;
TCHAR absoluteFilename[MAX_PATH];
DWORD size = MAX_PATH;
// configures structure with known data
d.number = FILE_NUMBER;
strcpy(d.string, FILE_STRING);
// convert from relative to absolute path
strcpy(absoluteFilename, AUX_FILENAME);
CPPUNIT_ASSERT( RelativeToAbsolutePath(absoluteFilename, &size) );
// executes action
fixture-＞setData(&d);
CPPUNIT_ASSERT( fixture-＞store("data.tmp") );
// Read both files contents and check results
// ReadAllFileInMemory is an auxiliar function which allocates a buffer
// and save all file content inside it. Caller should release the buffer.
tmpSize = ReadAllFileInMemory("data.tmp", tmpBuff);
auxSize = ReadAllFileInMemory(absoluteFilename, auxBuff);
// files must exist
CPPUNIT_ASSERT_MESSAGE("New file doesn't exists?", tmpSize ＞ 0);
CPPUNIT_ASSERT_MESSAGE("Aux file doesn't exists?", auxSize ＞ 0);
// sizes must be valid
CPPUNIT_ASSERT(tmpSize != 0xFFFFFFFF);
CPPUNIT_ASSERT(auxSize != 0xFFFFFFFF);
// buffers must be valid
CPPUNIT_ASSERT(tmpBuff != NULL);
CPPUNIT_ASSERT(auxBuff != NULL);
// both file's sizes must be the same as DATA's size
CPPUNIT_ASSERT_EQUAL((DWORD) sizeof(DATA), tmpSize);
CPPUNIT_ASSERT_EQUAL(auxSize, tmpSize);
// both files content must be the same
CPPUNIT_ASSERT( 0 == memcmp(tmpBuff, auxBuff, sizeof(DATA)) );
delete [] tmpBuff;
delete [] auxBuff;
::DeleteFile("data.tmp");
}
调用用户接口
最后，我们看看用一个mfc 对话框（TestRunner.dll）用来说明。
我们需要在我们的初始化函数中做如下初始化 #include ＜cppunit/ui/mfc/TestRunner.h＞
#include ＜cppunit/extensions/TestFactoryRegistry.h＞
BOOL CMy_TestsApp::InitInstance()
{
....
// declare a test runner, fill it with our registered tests and run them
CppUnit::MfcUi::TestRunner runner;
runner.addTest( CppUnit::TestFactoryRegistry::getRegistry().makeTest() );
runner.run();
return TRUE;
}
只要定义一个test的实例，然后注册所有用例，在跑case。
每发现一个错误时9比如发现内部数据和外部数据不同我们就创建一个异常，使用 CPPUNIT_FAIL(message) 来显示异常信息。
