GMock - 使用ON_CALL为重载方法返回默认值

Question

我正在尝试为包含三个重载方法的类编写mock,即:

#include <gtest/gtest.h>
#include <gmock/gmock.h>

using ::testing::_;
using ::testing::Return;
using ::testing::A;
using ::testing::ByRef;
using ::testing::Ref;
using ::testing::TypedEq;

struct Foo {
  int fooMethod(const int& intParam) { return 0; }
  int fooMethod(const float& floatParam) { return 0; }
  int fooMethod(const std::string& stringParam) { return 0; }
};

struct FooMock {
  FooMock() {
    ON_CALL(*this, fooMethod(_)).WillByDefault(Return(-1));
  }

  MOCK_METHOD1(fooMethod, int(const int& intParam));
  MOCK_METHOD1(fooMethod, int(const float& floatParam));
  MOCK_METHOD1(fooMethod, int(const std::string& stringParam));
};

但这会给出一个错误:

 error: call of overloaded ‘gmock_fooMethod(const testing::internal::AnythingMatcher&)’ is ambiguous

我也尝试过TypedEq()而不是"_",但它会给出更多模糊的错误.我检查了GMock常见问题解答,Wiki并没有找到解决方案 - 如何为重载方法返回ON_CALL的默认值？

BR,卢卡斯

Answer 1

@ tx34有答案的关键,但代码中还有一些问题.

首先,关于在重载函数之间选择的文档是最合适的.您有三个fooMethod具有相同数量的参数但参数类型不同的重载.您将不得不使用指定类型的匹配器.

接下来,你需要定义所有的Foo功能,这将被嘲笑为virtual,否则调用它们通过一个Foo对象就不会调用派生模拟功能.由于您要定义Foo为基类,因此它还应该有一个虚拟析构函数来避免切片.

最后,你需要FooMock继承Foo.

所以把它们放在一起,你得到的结果如下:

#include <memory>
#include <string>
#include "gtest/gtest.h"
#include "gmock/gmock.h"

using ::testing::_;
using ::testing::An;
using ::testing::Matcher;
using ::testing::TypedEq;
using ::testing::Return;

struct Foo {
  virtual ~Foo() {}
  virtual int fooMethod(const int&) { return 0; }
  virtual int fooMethod(const float&) { return 0; }
  virtual int fooMethod(const std::string&) { return 0; }
};

struct FooMock : Foo {
  FooMock() : Foo() {
    ON_CALL(*this, fooMethod(An<const int&>())).
        WillByDefault(Return(-1));
    ON_CALL(*this, fooMethod(Matcher<const float&>(_))).
        WillByDefault(Return(-2));
    ON_CALL(*this, fooMethod(TypedEq<const std::string&>("1"))).
        WillByDefault(Return(-3));
  }

  MOCK_METHOD1(fooMethod, int(const int& intParam));
  MOCK_METHOD1(fooMethod, int(const float& floatParam));
  MOCK_METHOD1(fooMethod, int(const std::string& stringParam));
};

TEST(Foo, foo) {
  std::shared_ptr<Foo> foo(new FooMock);
  auto foo_mock(std::dynamic_pointer_cast<FooMock>(foo));

  EXPECT_CALL(*foo_mock, fooMethod(Matcher<const int&>(_))).Times(1);
  EXPECT_CALL(*foo_mock, fooMethod(Matcher<const float&>(_))).Times(1);
  EXPECT_CALL(*foo_mock, fooMethod(Matcher<const std::string&>(_))).Times(1);

  EXPECT_EQ(-1, foo->fooMethod(1));
  EXPECT_EQ(-2, foo->fooMethod(1.0f));
  EXPECT_EQ(-3, foo->fooMethod("1"));
}


int main(int argc, char **argv) {
  testing::InitGoogleTest(&argc, argv);
  return RUN_ALL_TESTS();
}