gtest mock error no matching function for call

Question

I am mocking a class and would like to redirect calls ,but an error occured mean no matching function for call，code like this：

class MockCCHandler : public CCHandler {
public:
    MockCCHandler() {}
    ~MockCCHandler() override = default;
    MOCK_METHOD0(GetIdcName, string());
    MOCK_METHOD0(GetCurrentCityRT, City());
    MOCK_METHOD2(GetSetAttInfo, void(const string& business_direction, vector<SetAttrCfg>& set_attributes));
    MOCK_METHOD1(GetCkvConf, CkvCfgL5(const string&));

    CCHandlerPtr GetMockPtr();

 private:
    vector<SetAttrCfg> MakeSetAttrCfg();

    CkvCfgL5 MakeCkvCfgL5();
    CkvCfgL5 MakeCrossCityCkvCfgL5();
};

CCHandlerPtr MockCCHandler::GetMockPtr() {
    std::shared_ptr<MockCCHandler> cc_handler = std::make_shared<MockCCHandler>();

    EXPECT_CALL(*cc_handler, GetIdcName())
    .Times(1)
    .WillOnce(::testing::Return("BX"));

    EXPECT_CALL(*cc_handler, GetCurrentCityRT())
    .Times(1)
    .WillOnce(::testing::Return(City("Shenzhen")));

    EXPECT_CALL(*cc_handler, GetSetAttInfo(::testing::_, ::testing::_))
    .Times(1)
    .WillOnce([&](const string& business_direction, vector<SetAttrCfg>& set_attributes) {
        set_attributes = MakeSetAttrCfg();
    });


    EXPECT_CALL(*cc_handler, GetCkvConf(::testing::_))
    .Times(2)
    .WillOnce(::testing::Return(MakeCkvCfgL5()))
    .WillOnce(::testing::Return(MakeCrossCityCkvCfgL5()));

    return cc_handler;
}

when Compile this code, compiler show the error,no matching function for call to 'testing::internal::TypedExpectation<void(const std::basic_string&, std::vector&)>::WillOnce(MockCCHandler::GetMockPtr()::__lambda0)' });

mock/cc_handler_mock.cc:18:6:error: no matching function for call to 'testing::internal::TypedExpectation<void(const std::basic_string<char>&, std::vector<SetAttrCfg>&)>::WillOnce(MockCCHandler::GetMockPtr()::__lambda0)'
     });
      ^
mock/cc_handler_mock.cc:18:6: note: candidate is:
In file included from gtest/include/gmock/gmock-generated-function-mockers.h:43:0,
                 from gtest/include/gmock/gmock.h:61,
                 from mock/cc_handler_mock.h:3,
                 from mock/cc_handler_mock.cc:1:
gtest/include/gmock/gmock-spec-builders.h:994:21: note: testing::internal::TypedExpectation<F>& testing::internal::TypedExpectation<F>::WillOnce(const testing::Action<F>&) [with F = void(const std::basic_string<char>&, std::vector<SetAttrCfg>&)]
   TypedExpectation& WillOnce(const Action<F>& action) {
                     ^
gtest/include/gmock/gmock-spec-builders.h:994:21: note:   no known conversion for argument 1 from 'MockCCHandler::GetMockPtr()::__lambda0' to 'const testing::Action<void(const std::basic_string<char>&, std::vector<SetAttrCfg>&)>&'

Answer 1

You didn't mention GoogleTest version used, but passing a callable directly as action seems to be supported only since 1.10. Before that, you should use Invoke function to create an action:

EXPECT_CALL(*cc_handler, GetSetAttInfo(::testing::_, ::testing::_))
    .Times(1)
    .WillOnce(::testing::Invoke(
        [&](const string& business_direction, vector<SetAttrCfg>& set_attributes) {
            set_attributes = MakeSetAttrCfg();
        }
    ));

---

Side note: .Times(1) adds nothing when paired with WillOnce. When cardinality (.Times() call) is omitted, GoogleMock will deduce number of calls from the .WillOnce()/.WillRepeatedly() calls.