使用 GoogleMock 指定输出字符串参数

Question

我正在评估 Google Test/Mock 作为我的 C 代码单元测试的框架。

如何为要模拟的函数指定输出字符串参数？

这里我有 int get_int_param(const char *) 是要测试的函数，它使用了我要模拟的 int _get_text_file_content(const char *fn, char *content) 函数。

如何指定这个char *content，它将成为模拟函数的执行结果？

我正在为这段代码苦苦挣扎：

TEST(GetParameterTest,Positiv){
   const static int strLen=29;
   char *text=(char *)calloc(strLen,1);
   strcpy(text, "param1=1\nparam2=42\nparam3=3");

   MokedFunctions mokedFunctions;
   EXPECT_CALL(mokedFunctions, _get_text_file_content("process.conf",_)).Times(AtLeast(1)).WillOnce(SetArgReferee<1>(text));

   EXPECT_EQ(1, get_int_param("param1"));
}

并得到这个编译错误：

/usr/include/gmock/gmock-more-actions.h: In instantiation of ‘typename 
testing::internal::Function<F>::Result testing::SetArgRefereeActionP<k, 
value_type>::gmock_Impl<F>::gmock_PerformImpl(const args_type&, 
arg0_type, arg1_type, arg2_type, arg3_type, arg4_type, arg5_type, 
arg6_type, arg7_type, arg8_type, arg9_type) const [with arg0_type = 
const char*; arg1_type = char*; arg2_type = 
testing::internal::ExcessiveArg; arg3_type = 
testing::internal::ExcessiveArg; arg4_type = 
testing::internal::ExcessiveArg; arg5_type = 
testing::internal::ExcessiveArg; arg6_type = 
testing::internal::ExcessiveArg; arg7_type = 
testing::internal::ExcessiveArg; arg8_type = 
testing::internal::ExcessiveArg; arg9_type = 
testing::internal::ExcessiveArg; F = int(const char*, char*); int k = 1; 
value_type = char*; typename testing::internal::Function<F>::Result = 
int; testing::SetArgRefereeActionP<k, 
value_type>::gmock_Impl<F>::args_type = std::tuple<const char*, char*>]’:

 /usr/include/gmock/gmock-generated-actions.h:664:23:   required from 
 ‘static Result testing::internal::ActionHelper<Result, 
 Impl>::Perform(Impl*, const std::tuple<_U1, _U2>&) [with A0 = const 
 char*; A1 = char*; Result = int; Impl = 
 testing::SetArgRefereeActionP<1, char*>::gmock_Impl<int(const char*, 
 char*)>]’

 /usr/include/gmock/gmock-more-actions.h:168:1:   required from 
 ‘testing::SetArgRefereeActionP<k, 
 value_type>::gmock_Impl<F>::return_type 
 testing::SetArgRefereeActionP<k, 
 value_type>::gmock_Impl<F>::Perform(const args_type&) [with F = 
 int(const char*, char*); int k = 1; value_type = char*; 
 testing::SetArgRefereeActionP<k, 
 value_type>::gmock_Impl<F>::return_type = int; 
 testing::SetArgRefereeActionP<k, value_type>::gmock_Impl<F>::args_type 
 = std::tuple<const char*, char*>]’

 test_param.cpp:68:1:   required from here
 /usr/include/gmock/gmock-more-actions.h:175:3: error: size of array is negative
 GTEST_COMPILE_ASSERT_(internal::is_reference<argk_type>::value,
 ^
 In file included from /usr/include/gmock/gmock.h:65:0,
             from test_param.cpp:2:
  /usr/include/gmock/gmock-more-actions.h:177:28: error: assignment of read-only location ‘std::get<1u, {const char*, char*}>((* & args))’
    ::std::tr1::get<k>(args) = value;
                        ^
  make[1]: *** [test_param.o] Error 1

我做错了什么？

Answer 1

SetArgReferee 期望参数是 C++ 引用，这不是你的情况。

一般来说，为了更好地理解这些操作，将它们视为对参数 arg 的操作会有所帮助：

• SetArgPointee(value) 本质上是*arg = value（arg 必须是指针）
• SetArgReferee(value) 是 arg = value（arg 必须是引用）
• SetArrayArgument(first, last) 是 memcpy(arg, first, last - first)（arg 必须是指针）
• SaveArg(ptr) 是 *ptr = arg
• SaveArgPointee(ptr) 是 *ptr = *arg（arg 必须是指针）

鉴于此，很明显您需要的操作是SetArrayArgument<1>(text, text + strlen(text) + 1)。

Answer 2

您正在为 C 代码使用 C++ 测试框架。除非你愿意用 g++（而不是 gcc）编译你的代码，否则它是行不通的。 Gcc 无法编译 C++ 代码。