Give object as parameter for test

Question

I trying to write a test that checks that a method isn't overwritten incorrectly in derived classes. So I tried the following. But no matter what I try it doesn't seem to allow me to "inject" my object.

[Theory]
[xxxData(new BaseClass())]
[xxxData(new DerivedClass())]
public void Test_Stuff(BaseClass obj)
{
    // ...
}

Answer 1

Assuming I understand your goal, I see two ways:

1. Using InlineDataAttribute and passing Types

2. Using MemberDataAttribute (PropertyData in xunit.net v1)

   [Theory]
   [InlineData(typeof(BaseClass))]
   [InlineData(typeof(DerivedClass))]
   public void Test_Stuff(Type type/*BaseClass obj*/)
   {
       var obj = Activator.CreateInstance(type) as BaseClass;
       CheckConstrain(obj);
   }
   
   
   [Theory]
   [MemberData("GetObjects")]
   public void Test_Stuff2(BaseClass obj)
   {
       CheckConstrain(obj);
   }
   
   public static IEnumerable<object[]> GetObjects
   {
       get
       {
          return new[] 
          {
           new object[] { new BaseClass() },
           new object[] { new DerivedClass() }
          };
       }
   }
   
   private static void CheckConstrain(BaseClass baseClass)
   {
       Assert.True(baseClass.Foo() <= 1);
   }
   

See also this related answer Pass complex parameters to [Theory]