Testing general DynamoDBMarshalling for enums

I have a DynamoDBMarsheller that is very similar to this. It looks like:

public class EnumMarshaller implements DynamoDBMarshaller<Enum> {
    @Override
    public String marshall(Enum getterReturnResult) {
        return getterReturnResult.name();
    }

    @Override
    public Enum unmarshall(Class<Enum> clazz, String obj) {
        return Enum.valueOf(clazz, obj);
    }
}

Now I am stuck on trying to test it. I have tried doing something along the lines of (where Status is a normal Enum):

    @Test
    public void shouldTurnStringToEnum() {
        final Class<? extends Enum> enumType = Status.class;

        assertThat(marshaller.unmarshall(enumType, "failed"), is(marshaller.marshall(Status.FAILED)));
    }

however I can't get the enum type variable right. Is this even possible?