C++ unit test testing, using template test class - c++

Question

I’m doing some C++ test driven development. I have a set of classes the do the same thing e.g.
same input gives same output (or should, that’s what I’m try to test). I’m using Visual Studio 2012’s
CppUnitTestFramework. I wanted to create a templated test class, so I write the tests once, and can template in classes as needed however I cannot find a way to do this. My aim:
/* two classes that do the same thing */
class Class1
{
int method()
{
return 1;
}
};
class Class2
{
int method()
{
return 1;
}
};
/* one set of tests for all classes */
template< class T>
TEST_CLASS(BaseTestClass)
{
TEST_METHOD(testMethod)
{
T obj;
Assert::AreEqual( 1, obj.method());
}
};
/* only have to write small amout to test new class */
class TestClass1 : BaseTestClass<Class1>
{
};
class TestClass2 : BaseTestClass<Class1>
{
};
Is there a way I can do this using CppUnitTestFramework?
Is there another unit testing framework that would allow me to do this?

Answer 1

I do not know if there is a way to do this with CppUnitTestFramework,
with which I am unfamiliar, but something you can certainly
do in googletest
is specify an arbitrary list of classes and have the framework
generate (template-wise) the same test(s) for all of them. I think that
would fit your bill.
You can download googletest as source here.
The idiom you will want is:
typedef ::testing::Types</* List of types to test */> MyTypes;
...
TYPED_TEST_CASE(FooTest, MyTypes);
...
TYPED_TEST(FooTest, DoesBlah) {
/* Here TypeParam is instantiated for each of the types
in MyTypes. If there are N types you get N tests.
*/
// ...test code
}
TYPED_TEST(FooTest, DoesSomethingElse) {
// ...test code
}
Study the primer and
the samples. Then go to
the AdvancedGuide
for Typed Tests
Also check out More Assertions

Answer 2

I had a similar problem: I have an interface and several implementations of it. Of course I do only want to write tests against the interface. Also, I do not want to copy my tests for each implementation.
Well, my solution is not very pretty but it is straightforward and the only one I came up with until now.
You could do the same for Class1 and Class2 and then add more specialized tests for each implementation.
setup.cpp
#include "stdafx.h"
class VehicleInterface
{
public:
VehicleInterface();
virtual ~VehicleInterface();
virtual bool SetSpeed(int x) = 0;
};
class Car : public VehicleInterface {
public:
virtual bool SetSpeed(int x) {
return(true);
}
};
class Bike : public VehicleInterface {
public:
virtual bool SetSpeed(int x) {
return(true);
}
};
#define CLASS_UNDER_TEST Car
#include "unittest.cpp"
#undef CLASS_UNDER_TEST
#define CLASS_UNDER_TEST Bike
#include "unittest.cpp"
#undef CLASS_UNDER_TEST
unittest.cpp
#include "stdafx.h"
#include "CppUnitTest.h"
#define CONCAT2(a, b) a ## b
#define CONCAT(a, b) CONCAT2(a, b)
using namespace Microsoft::VisualStudio::CppUnitTestFramework;
TEST_CLASS(CONCAT(CLASS_UNDER_TEST, Test))
{
public:
CLASS_UNDER_TEST vehicle;
TEST_METHOD(CONCAT(CLASS_UNDER_TEST, _SpeedTest))
{
Assert::IsTrue(vehicle.SetSpeed(42));
}
};
You will need to exclude „unittest.cpp“ from build.