CODEWITHSUNDEEP
c#typesmstest
Patrik Schweigl
Patrik Schweigl

Reputation: 93

reverse typeof(T) to use type in tests

I have a factory method Create<T>() which returns an instance of a given interface type T. The Factory pattern works, but now I have to write test in MSTest for our Factory. The tests should check if the instance of our create method is the right one. Basically, I want to do something like this:

[DataTestMethod]
[DataRow(typeof(Member), typeof(MemberImpl))]
public void Test1(Type interfaceType, Type implType)
{
    implType instance = PlanungContribution.Create<interfaceType>();
}

The problem is, that the DataRow can only have a typeof(T) and not T as a parameter. So I have to revert the typeof(T) operator.

How can I achieve this? Is there a better way to do something like this?

[EDIT]

[DataTestMethod]
[DataRow(typeof(Mitarbeiter), typeof(MitarbeiterImpl))]
public void Test1(Type interfaceType, Type baseType)
{
    var t = typeof(ModelContributionPlanungEF6).GetMethod("Create").MakeGenericMethod(interfaceType).Invoke(PlanungContribution, new object[0]);
    Assert.AreEqual(baseType, t);
}

Assert.AreEqual failed, because they are not the same. Look closely:

Message: Assert.AreEqual failed.

Expected: DP.PMS.EF6.Planung.MitarbeiterImpl (System.RuntimeType).

Actual:DP.PMS.EF6.Planung.MitarbeiterImpl (DP.PMS.EF6.Planung.MitarbeiterImpl).

Upvotes: 0

Views: 1167

Answers (2)

MakePeaceGreatAgain
MakePeaceGreatAgain

Reputation: 37070

You have to invoke the generic method via reflection first and invoke it. Afterwards check the returned type:

[DataTestMethod]
[DataRow(typeof(Member), typeof(MemberImpl))]
public void Test1(Type interfaceType, Type implType)
{
    var method = typeof(PlanungContribution).GetMethod("Create").MakeGenericMethod(interfaceType);
    var instance = method.Invoke(null, new object[0]);
    var type = instance.GetType();
    Assert.AreEqual(type, implType);
}

Upvotes: 0

Titian Cernicova-Dragomir
Titian Cernicova-Dragomir

Reputation: 250136

You need to use reflection to achieve this :

typeof(PlanungContribution).GetMethod("Create").MakeGenericMethod(interfaceType)
    .Invoke(null /*Instance to call on , if static pass null */, new object[0]);

Upvotes: 1

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