public void TestInvalidMessageReceivment(string messageText) { var fakeMessage = new Mock <ITweet>(); fakeMessage.Setup(m => m.RetrieveMessage()) .Returns(messageText); var fakeServer = new Mock <IServer>(); fakeServer.Setup(s => s.ReceiveMessage(fakeMessage.Object)) .Returns(false); var expectedValue = false; var microwaveOven = new MicrowaveOven(fakeServer.Object); bool actualValue = microwaveOven.ReceiveMessage(fakeMessage.Object); Assert.That(actualValue, Is.EqualTo(expectedValue)); }