C++ unit test testing, using template test class

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?

Griner

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

Versed

Cheers for the answer. For anyone looking at this googletest is a little bit of a pain to get going. I used a combination of these to guides blog.knatten.org/2012/09/26/… and #532441. It does not compile in Visual Studio 2012 unless you set compiler to be 2010 version in the project properties. – Griner

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.

Radiotelegram