class MyClass { static public int StaticMethod() { return 1; } public int InstanceMethod() { return 1;} } [Test] public void Test() { Isolate.Fake.StaticMethods<MyClass>(); Isolate.WhenCalled(() => MyClass.StaticMethod).WillReturn(2); var fakedInstance = Isolate.Fake.Instance<MyClass>(); Isolate.WhenCalled(() => fakedInstance.InstanceMethod).WillReturn(3); Assert.That(MyClass.StaticMethod(), Is.EqualTo(2)); Assert.That(fakedInstance.InstanceMethod(), Is.EqualTo(3)); }