EXPECT_CALL on template mock - c++

Question

I have mock defined as follows:
template<typename T>
class ParseTreeMock : public ParseTreeInterface<T> {
public:
MOCK_METHOD1(fillConfigTree, void(std::string const&));
MOCK_METHOD1_T(getProperty, T(std::string const&));
ParseTreeMock(): parseTree(std::make_unique<pt::ptree>()) {
}
static std::unique_ptr<ParseTreeInterface<T>> getDefaultTree() {
return std::make_unique<ParseTreeMock<T>>();
}
private:
std::unique_ptr<pt::ptree> parseTree;
};
which is created later in test case:
class ConfigTest : public ::testing::Test {
protected:
std::unique_ptr<ParseTreeInterface<std::string>> treeMock;
virtual void SetUp() {
treeMock = ParseTreeMock<std::string>::getDefaultTree();
}
};
And I want to set return specific value on getProperty method:
EXPECT_CALL(*treeMock, getProperty("miniReaderConfig.cacheConfig.cacheOnOff")).willOnce(Return(false));
I get error:
In file included from ./lib/googletest/googlemock/include/gmock/gmock-generated-function-mockers.h:43:0,
from ./lib/googletest/googlemock/include/gmock/gmock.h:61,
from ./test/UT/Mocks/ParseTreeMock.hpp:2,
from test/UT/Configuration/ConfigTest.cpp:1:
test/UT/Configuration/ConfigTest.cpp: In member function ‘virtual void ConfigTest_CreateConfigurationWithoutErrors_Test::TestBody()’:
./lib/googletest/googlemock/include/gmock/gmock-spec-builders.h:1844:12: error: ‘class miniReader::Configuration::ParseTreeInterface<std::__cxx11::basic_string<char> >’ has no member named ‘gmock_getProperty’; did you mean ‘getProperty’?
((obj).gmock_##call).InternalExpectedAt(__FILE__, __LINE__, #obj, #call)
Any solution with explanation of error appreciated.

Answer 1

The treeMock variable needs to be of type std::unique_ptr<ParseTreeMock<std::string>>, and then static method needs to look like this
static std::unique_ptr<ParseTreeMock<T>> getDefaultTree()
{
return std::make_unique<ParseTreeMock<T>>();
}
Typically you instantiate a class that implements an interface in your test and then pass the instance to the class that you are testing, and with EXPECT_CALLs you make sure that the class you are testing calls the callbacks on your mock object.
Not related to the error you got, but WillOnce needs to be spelled with the first letter capitalized. Also, since you set the template variable to std::string, the EXPECT_CALL can't expect that a boolean is returned.
This compiles for me:
namespace pt { struct ptree {};}
template<typename T>
class ParseTreeInterface
{
public:
virtual void fillConfigTree(std::string const&) = 0;
virtual T getProperty(std::string const&) = 0;
};
template<typename T>
class ParseTreeMock : public ParseTreeInterface<T> {
public:
MOCK_METHOD1(fillConfigTree, void(std::string const&));
MOCK_METHOD1_T(getProperty, T(std::string const&));
ParseTreeMock(): parseTree(std::make_unique<pt::ptree>()) {
}
static std::unique_ptr<ParseTreeMock<T>> getDefaultTree()
{
return std::make_unique<ParseTreeMock<T>>();
}
private:
std::unique_ptr<pt::ptree> parseTree;
};
class ConfigTest : public ::testing::Test {
protected:
std::unique_ptr<ParseTreeMock<std::string>> treeMock;
virtual void SetUp() {
treeMock = ParseTreeMock<std::string>::getDefaultTree();
}
};
TEST_F(ConfigTest, test)
{
EXPECT_CALL(*treeMock, getProperty("miniReaderConfig.cacheConfig.cacheOnOff")).WillOnce(::testing::Return(""));
}