c++ - 在 gmock 中使用指向带有 EXPECT_CALL 的模拟对象的指针会导致段错误或默认处理程序启动

Question

我正在使用 gmock 来模拟一个底层库，同时我正在测试我的包装器。我注意到 gmock 需要预先定义模拟对象。我想要的是传递一个指向模拟对象的指针。如果测试错误处理所需的对象是动态创建的，则它不起作用。

引用:gmock/google-mock issues warning and fails the test with mocking exceptions
代码:

测试/mock_turtle_test.cc

#include "mock_turtle.h"
#include "../painter.h"
#include <gtest/gtest.h>

using  ::testing::_;
using  ::testing::AtLeast;
using  ::testing::Return;
ACTION(MyException)
{
        throw(error_k());
}
TEST(PainterTest, CanDrawSomething) {
  Painter painter;
  EXPECT_CALL(*(painter.getTurtle()), PenDown())
      .Times(AtLeast(1))
      .WillOnce(MyException())
      .WillRepeatedly(Return(5));
  EXPECT_TRUE(painter.DrawCircle(0, 0, 10));
}

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

inc/mock_turtle.h

#pragma once
#include <cstdlib>
#include "turtle.h"
#include <gmock/gmock.h>

class Turtle : public FakeTurtle{
 public:
  using FakeTurtle::FakeTurtle;
  MOCK_METHOD((void), PenUp, ());
  MOCK_METHOD((int), PenDown, ());
  MOCK_METHOD((void), Forward, (int distance));
  MOCK_METHOD((void), Turn, (int degrees));
  MOCK_METHOD((void), GoTo, (int x, int y));
  MOCK_METHOD((int), GetX, ());
  MOCK_METHOD((int), GetY, ());
};

公司/乌龟.h

#pragma once

class FakeTurtle {

public:
  virtual ~FakeTurtle() {}
  virtual void PenUp() {};
  virtual int PenDown() {};
  virtual void Forward(int distance) {};
  virtual void Turn(int degrees) {};
  virtual void GoTo(int x, int y) {};
  virtual int GetX() const {};
  virtual int GetY() const {};

};

画家.h

#pragma once
#include "turtle.h"
#include <cerrno>

class error_k
{
public:
    error_k() : errnum(EAGAIN){}
    int num() const
    {
        return errnum;
    }
private:
    int errnum;
};

class Painter
{
        Turtle* turtle;
public:
        Painter() : turtle(new Turtle){}
        //Painter(){}
    Turtle** getTurtle(){
        return &turtle;
    }
        bool DrawCircle(int, int, int){
        int rep = 10;
        int ret = 0;
        delete turtle;
        turtle = new Turtle;
        do{
            try{
                std::cout << "calling PenDown() : rep = " <<
                    rep << " , ret = " << ret << std::endl;
                        ret = turtle->PenDown();
                if(ret > 0)
                    return true;
            }catch(error_k err )
            {
                std::cout << "Caught Exception (" <<
                    err.num() << "): rep = " <<
                    rep << " , ret = " << ret << std::endl;

                delete turtle;
                turtle = new Turtle();
            }
        }while(rep-- > 0 && ret == 0); 
                return false;
        }
    ~Painter(){
        delete turtle;
    }
};

CmakeLists.txt

cmake_minimum_required(VERSION 2.6)

# Locate GTest
find_package(GTest REQUIRED)
find_package(PkgConfig)
message(STATUS "gtest found: " ${GTEST_FOUND})
pkg_check_modules(GMOCK "gmock" REQUIRED)
message(STATUS "gmock found: " ${GMOCK_FOUND})

include_directories(${GTEST_INCLUDE_DIRS})

# Link runTests with what we want to test and the GTest and pthread library
add_executable(runTests test/mock_turtle_test.cc)
target_link_libraries(runTests ${GTEST_LIBRARIES} ${GMOCK_LIBRARIES} gmock gmock_main gtest gtest_main)
target_include_directories(runTests SYSTEM PRIVATE inc)
add_test(NAME runTests COMMAND runTests)
enable_testing()

输出:

$ make ; ./runTests 
Scanning dependencies of target runTests
[ 50%] Building CXX object CMakeFiles/runTests.dir/test/mock_turtle_test.cc.o
[100%] Linking CXX executable runTests
[100%] Built target runTests
[==========] Running 1 test from 1 test suite.
[----------] Global test environment set-up.
[----------] 1 test from PainterTest
[ RUN      ] PainterTest.CanDrawSomething
/home/preetam/Desktop/gmock/cpp_mock_ptr/test/mock_turtle_test.cc:16: Failure
Actual function call count doesn't match EXPECT_CALL(**tt, PenDown())...
         Expected: to be called at least once
           Actual: never called - unsatisfied and active
calling PenDown() : rep = 10 , ret = 0

GMOCK WARNING:
Uninteresting mock function call - returning default value.
    Function call: PenDown()
          Returns: 0
NOTE: You can safely ignore the above warning unless this call should not happen.  Do not suppress it by blindly adding an EXPECT_CALL() if you don't mean to enforce the call.  See https://github.com/google/googletest/blob/master/googlemock/docs/cook_book.md#knowing-when-to-expect for details.
calling PenDown() : rep = 9 , ret = 0

GMOCK WARNING:
Uninteresting mock function call - returning default value.
    Function call: PenDown()
          Returns: 0
NOTE: You can safely ignore the above warning unless this call should not happen.  Do not suppress it by blindly adding an EXPECT_CALL() if you don't mean to enforce the call.  See https://github.com/google/googletest/blob/master/googlemock/docs/cook_book.md#knowing-when-to-expect for details.
calling PenDown() : rep = 8 , ret = 0

GMOCK WARNING:
Uninteresting mock function call - returning default value.
    Function call: PenDown()
          Returns: 0
NOTE: You can safely ignore the above warning unless this call should not happen.  Do not suppress it by blindly adding an EXPECT_CALL() if you don't mean to enforce the call.  See https://github.com/google/googletest/blob/master/googlemock/docs/cook_book.md#knowing-when-to-expect for details.
calling PenDown() : rep = 7 , ret = 0

GMOCK WARNING:
Uninteresting mock function call - returning default value.
    Function call: PenDown()
          Returns: 0
NOTE: You can safely ignore the above warning unless this call should not happen.  Do not suppress it by blindly adding an EXPECT_CALL() if you don't mean to enforce the call.  See https://github.com/google/googletest/blob/master/googlemock/docs/cook_book.md#knowing-when-to-expect for details.
calling PenDown() : rep = 6 , ret = 0

GMOCK WARNING:
Uninteresting mock function call - returning default value.
    Function call: PenDown()
          Returns: 0
NOTE: You can safely ignore the above warning unless this call should not happen.  Do not suppress it by blindly adding an EXPECT_CALL() if you don't mean to enforce the call.  See https://github.com/google/googletest/blob/master/googlemock/docs/cook_book.md#knowing-when-to-expect for details.
calling PenDown() : rep = 5 , ret = 0

GMOCK WARNING:
Uninteresting mock function call - returning default value.
    Function call: PenDown()
          Returns: 0
NOTE: You can safely ignore the above warning unless this call should not happen.  Do not suppress it by blindly adding an EXPECT_CALL() if you don't mean to enforce the call.  See https://github.com/google/googletest/blob/master/googlemock/docs/cook_book.md#knowing-when-to-expect for details.
calling PenDown() : rep = 4 , ret = 0

GMOCK WARNING:
Uninteresting mock function call - returning default value.
    Function call: PenDown()
          Returns: 0
NOTE: You can safely ignore the above warning unless this call should not happen.  Do not suppress it by blindly adding an EXPECT_CALL() if you don't mean to enforce the call.  See https://github.com/google/googletest/blob/master/googlemock/docs/cook_book.md#knowing-when-to-expect for details.
calling PenDown() : rep = 3 , ret = 0

GMOCK WARNING:
Uninteresting mock function call - returning default value.
    Function call: PenDown()
          Returns: 0
NOTE: You can safely ignore the above warning unless this call should not happen.  Do not suppress it by blindly adding an EXPECT_CALL() if you don't mean to enforce the call.  See https://github.com/google/googletest/blob/master/googlemock/docs/cook_book.md#knowing-when-to-expect for details.
calling PenDown() : rep = 2 , ret = 0

GMOCK WARNING:
Uninteresting mock function call - returning default value.
    Function call: PenDown()
          Returns: 0
NOTE: You can safely ignore the above warning unless this call should not happen.  Do not suppress it by blindly adding an EXPECT_CALL() if you don't mean to enforce the call.  See https://github.com/google/googletest/blob/master/googlemock/docs/cook_book.md#knowing-when-to-expect for details.
calling PenDown() : rep = 1 , ret = 0

GMOCK WARNING:
Uninteresting mock function call - returning default value.
    Function call: PenDown()
          Returns: 0
NOTE: You can safely ignore the above warning unless this call should not happen.  Do not suppress it by blindly adding an EXPECT_CALL() if you don't mean to enforce the call.  See https://github.com/google/googletest/blob/master/googlemock/docs/cook_book.md#knowing-when-to-expect for details.
calling PenDown() : rep = 0 , ret = 0

GMOCK WARNING:
Uninteresting mock function call - returning default value.
    Function call: PenDown()
          Returns: 0
NOTE: You can safely ignore the above warning unless this call should not happen.  Do not suppress it by blindly adding an EXPECT_CALL() if you don't mean to enforce the call.  See https://github.com/google/googletest/blob/master/googlemock/docs/cook_book.md#knowing-when-to-expect for details.
/home/preetam/Desktop/gmock/cpp_mock_ptr/test/mock_turtle_test.cc:20: Failure
Value of: painter.DrawCircle(0, 0, 10)
  Actual: false
Expected: true
[  FAILED  ] PainterTest.CanDrawSomething (0 ms)
[----------] 1 test from PainterTest (0 ms total)

[----------] Global test environment tear-down
[==========] 1 test from 1 test suite ran. (1 ms total)
[  PASSED  ] 0 tests.
[  FAILED  ] 1 test, listed below:
[  FAILED  ] PainterTest.CanDrawSomething

 1 FAILED TEST

Answer 1

你能创建一个 FakeTurtle 类型的模拟对象吗？并使用依赖注入(inject)技术(如果 Painter 需要成为注入(inject)对象的所有者，请参阅 Dependency injection with unique_ptr to mock；但首先尝试以 Painter 接受对 Turtle 的引用的方式重构您的代码，即在其构造函数中使用 Turtle& - 这更容易)。

GoogleMock 框架要求创建一个模拟对象，并且所有期望都设置在这个对象上(而不是其他一些对象)。

旁注:我会制作 Turtle纯虚拟界面。