public void TestUserRegistrationIfUserNotPresent()
{
User user = new User("ShilpaG", "test123", "*****@*****.**");
var mock = new Mock<IRepository>();
mock.Setup(ps => ps.IsUserPresent(user.Username)).Returns(false).AtMostOnce();
Assert.IsTrue(user.Register(mock.Object));
mock.VerifyAll();
}