public void Foo_AutoMoq_WithReturnValue() { _fixture.Customize(new AutoMoqCustomization()); Mock <IEmailGateway> mockGateway = _fixture.Freeze <Mock <IEmailGateway> >(); EmailMessageBuffer sut = _fixture.Create <EmailMessageBuffer>(); EmailMessage emailMessage = _fixture.Create <EmailMessage>(); string wasSent = sut.SendOne(emailMessage); wasSent.Should().Be("The call was successful."); mockGateway.Verify(x => x.Send(emailMessage), Times.Once); }