GoogleMock：如何精确预期具有特定参数的一次调用，并查看失败诊断？

也许是一个技巧问题，我的问题是，如果我写：

EXPECT_CALL(mock, handleMessage(_)).Times(0);                           // expectation #1
EXPECT_CALL(mock, handleMessage(Pointee(IsLike(aSpecificMessage))));    // expectation #2

...和方法handleMessage被调用一次，但有不同的参数（不是aSpecificMessage），那么失败看起来像：

Mock function called more times than expected - returning default value.
    Function call: handleMessage(0x8b5378)
          Returns: false
         Expected: to be never called
           Actual: called once - over-saturated and active

Google Mock 不会打印有关为什么参数与期望 #2 中的谓词不匹配的诊断信息。 这大概是因为期望 #1 是第一个失败的（？）。

如果我省略期望#1，那么失败就会很冗长，大致如下：

Google Mock tried the following 1 expectation, but it didn't match:

../../test/Test.cpp:143: EXPECT_CALL(mock, handleMessage(Pointee(IsLike(aSpecificMessage))))...
  Expected arg #0: points to a value that <....>
           Actual: 0xfeaf18, which points to <.....>

我正在使用自定义匹配器IsLike我经历了生成非常明确的不匹配原因的麻烦，我希望将它们打印出来。我也不想放弃期望#1，因为它位于“默认”部分，并且默认情况下我不希望在其余测试中调用该模拟。

看起来你应该使用the StrictMock模板修饰符 https://github.com/google/googletest/blob/master/googlemock/docs/CookBook.md#the-nice-the-strict-and-the-naggy。让我们使用这个简单的类和模拟：

struct Foo
{
    virtual void function(int) {
    }
};

struct MockFoo: public Foo
{
    MOCK_METHOD1(function, void(int x));
};

让我们从练习该方法的基本测试开始：

TEST(MockTest, basic_one_expectation)
{
    MockFoo foo;
    EXPECT_CALL(foo, function(4));
    Foo& foo1(foo);
    foo1.function(3);
}

Output:

[ RUN      ] MockTest.basic_one_expectation
unknown file: Failure

Unexpected mock function call - returning directly.
    Function call: function(3)
Google Mock tried the following 1 expectation, but it didn't match:

mock-test.cpp:298: EXPECT_CALL(foo, function(4))...
  Expected arg #0: is equal to 4
           Actual: 3
         Expected: to be called once
           Actual: never called - unsatisfied and active
mock-test.cpp:298: Failure
Actual function call count doesn't match EXPECT_CALL(foo, function(4))...
         Expected: to be called once
           Actual: never called - unsatisfied and active
[  FAILED  ] MockTest.basic_one_expectation (1 ms)
  

这是您已经考虑过的替代方案之一，但您不想要它，因为您还有其他测试，这些测试对函数是否被调用没有任何特定期望，并且您希望这些测试在函数被调用时失败反正。提醒一下，让我们看看尝试这样的测试时发生了什么：

TEST(MockTest, basic_no_expectation)
{
    MockFoo foo;
    Foo& foo1(foo);
    foo1.function(3);
}

Output:

[ RUN      ] MockTest.basic_no_expectation

GMOCK WARNING:
Uninteresting mock function call - returning directly.
    Function call: function(3)
Stack trace:
[       OK ] MockTest.basic_no_expectation (1 ms)
  

我们收到警告，但测试仍然通过。这对你没有好处。我们来看看有什么效果StrictMock has:

TEST(MockTest, strict_no_expectation)
{
    ::testing::StrictMock<MockFoo> foo;
    Foo& foo1(foo);
    foo1.function(3);
}

Output:

[ RUN      ] MockTest.strict_no_expectation
unknown file: Failure
Uninteresting mock function call - returning directly.
    Function call: function(3)
[  FAILED  ] MockTest.strict_no_expectation (0 ms)
  

我们不必明确表示我们不希望调用该函数，但是当无论如何调用该函数时，测试都会失败。正是您想要的。

最后，让我们看看会发生什么StrictMock在有的情况下are对函数参数的明确期望：

TEST(MockTest, strict_one_expectation)
{
    ::testing::StrictMock<MockFoo> foo;
    EXPECT_CALL(foo, function(4));
    Foo& foo1(foo);
    foo1.function(3);
}

Output:

[ RUN      ] MockTest.strict_one_expectation
unknown file: Failure

Unexpected mock function call - returning directly.
    Function call: function(3)
Google Mock tried the following 1 expectation, but it didn't match:

mock-test.cpp:307: EXPECT_CALL(foo, function(4))...
  Expected arg #0: is equal to 4
           Actual: 3
         Expected: to be called once
           Actual: never called - unsatisfied and active
mock-test.cpp:307: Failure
Actual function call count doesn't match EXPECT_CALL(foo, function(4))...
         Expected: to be called once
           Actual: never called - unsatisfied and active
[  FAILED  ] MockTest.strict_one_expectation (0 ms)
  

诊断显示参数不匹配的原因，就像原来的一样basic_one_expectation测试如上所示。