public void ShouldThrowIfUserIsAlreadyLoggedIn([Frozen]Mock<IAccessTokenConfiguration> accessTokenConfigurationMock, LoginUserCommand loginCommand) { accessTokenConfigurationMock.Setup(x => x.GetAccessToken()).Returns("foo"); var exception = Assert.Throws<CommandException>(() => loginCommand.Execute(new string[] { })); Assert.Equal("You're already logged in. You need to log out (\"logout\") before you can log in again.", exception.Message); }