Googlemock EXPECT_CALL 失败并出现错误：“operator==”不匹配（操作数类型为“const XX”

Question

我第一次使用 googlemock/test。编译错误是由于以下行：

EXPECT_CALL(orderWriter, writeOrders(aNonZeroSizeOrder))
    .Times(1);

错误：

error: 不匹配 'operator==' 操作数类型是 'const Order' 和 'const Order' 'const Order' 不是从 'const std::istream_iterator<_Tp, _CharT, _Traits, _Dist>'

派生的

注：候选：template bool std::operator==(const std::set<_Key, _Compare, _Alloc>&, const std::set<_Key, _Compare, _Alloc>&)

/usr/lib/gcc/x86_64-pc-cygwin/7.4.0/include/c++/bits/stl_algobase.h:800:22：注意：“const Order”不是从“const std::pair<_T1, _T2>”派生的 如果 (!(*__first1 == *__first2)) ~~~~~~~~~~~^~~~~~~~~~~~~

如果我评论它，编译成功。 我在使用 const ref 参数定义 Mock 方法时做错了什么吗？

class Order
{
    //represents an order
};

class OrderWriter
{
public:
    virtual void writeOrders(const std::vector<Order>& allOrders)
    {
        // ... writes the orders somewhere ...
    }
};

class OrderStore
{
public:
    virtual std::vector<Order> getOrders() const
    {
        // ... returns an array of orders ...
    }
};

class SimpleOrderManager
{
public:
    void writeAllOrders(OrderStore& orderStore, OrderWriter& orderWriter)
    {
        std::vector<Order> allOrders = orderStore.getOrders();

        if(allOrders.size() == 0)
            throw "No orders in store";
        orderWriter.writeOrders(allOrders);
    }
};

/////////////////////////////////////////////////////////////////////////////////////
//Need to mock class OrderStore as we need to return vector
//without changing original class OrderStore which is not implemented (thus not returning vector)
class MockOrderStore : public OrderStore
{
public:
    MOCK_CONST_METHOD0(getOrders, std::vector<Order> () );
};

//To check if OrderWriter::writeOrders() is called
class MockOrderWriter : public OrderWriter
{
public:
    MOCK_METHOD1(writeOrders, void (const std::vector<Order>& ) );
};

TEST(SimpleOrderManager_TestCase,  expect_call_writeOrders )
{
    std::vector<Order> aNonZeroSizeOrder{Order()};
    MockOrderStore  aMockOrderStore;
    MockOrderWriter aMockOrderWriter;
    SimpleOrderManager aSMO;
    //Call MockOrderStore::getOrders() not OrderStore::getOrders()
    //as we need to return empty vector without changing original class OrderStore
    EXPECT_CALL(aMockOrderStore, getOrders)
    .Times(1)
    .WillOnce(Return(aNonZeroSizeOrder));

/*i**************ERROR in this line **************************/
    EXPECT_CALL(aMockOrderWriter, writeOrders(aNonZeroSizeOrder)).Times(1);

    aSMO.writeAllOrders(aMockOrderStore, aMockOrderWriter);
}```

EDIT: Problems solved when I pass "_" instead of parameter as suggested by @PiotrNycz
It works when I change like this:
EXPECT_CALL(aMockOrderWriter, writeOrders(_)).Times(1);

Answer 1

当你写这篇文章时：

EXPECT_CALL(orderWriter, writeOrders(aNonZeroSizeOrder))
    .Times(1);

Googlemock 理解这一点：

EXPECT_CALL(orderWriter, writeOrders(::testing::Eq(aNonZeroSizeOrder)))
//                                   ^^^^^^^^^^^^^^
    .Times(1);

这是因为

EXPECT_CALL()

的参数中的 googlemock 期望匹配器 - 而不是值。当您提供简单的值时 - 它们会“静静地”转换为

::testing::Eq(value)

.

返回的匹配器

这样的

Eq

匹配器是用

operator==

实现的 - 所以你有错误。

你有两种解决方法：

1. 将

   operator ==

   添加到您的价值等级
2. 使用其他匹配器 - 比如

   ::testing::Field

   - 或者只是

   ::testing::_

   看看我是对的。

可用匹配器的完整列表在这里：CheatSheet.md#matchers