public void ShouldNotCreateUser_IfNameisInvalid(string firstName, string lastName)
        {
            // arrange
            SocialNetwork socialNetwork = new SocialNetwork();
            //string firstName = "aaaaa5ddddd", lastName = "Ice";

            // act
            bool result = socialNetwork.CreateUser(firstName, lastName);

            // assert
            Assert.False(result, "CreateUser returned true");
            Assert.Empty(socialNetwork.allUsers);
        }
        public void ShouldNotCreateUser_WhenUserAlreadyExists()
        {
            // arrange
            SocialNetwork socialNetwork = new SocialNetwork();
            string        firstName = "Gordon", lastName = "Brown";
            User          existingUser = new User(firstName, lastName);

            socialNetwork.allUsers.Add(existingUser);

            // act
            bool result = socialNetwork.CreateUser(firstName, lastName);

            // assert
            Assert.False(result, "Function returned true");
            Assert.Single(socialNetwork.allUsers);
        }
        public void ShouldCreateUser_ForCorrectParameters()
        {
            // arrange
            string        firstName = "Nils", lastName = "Holgersson";
            SocialNetwork socialNetwork = new SocialNetwork();

            // act
            bool result = socialNetwork.CreateUser(firstName, lastName);

            // assert
            Assert.True(result, "Did not return true");
            // assert that the created User actually is in the list allUsers
            bool exist = UserExist(socialNetwork.allUsers, firstName, lastName);

            Assert.True(exist, "No user with that name exist in allUsers");
        }