public void ShouldBeAbleToUpdateUsersFirstName()
{
InMemoryStorage storage = new InMemoryStorage();
int testedUserdId = 5;
string testedFirstName = "test";
UserModel testUser = new UserModel
{
Id = testedUserdId,
FirstName = testedFirstName,
LastName = "",
Birthdate = DateTime.Now
};
var result = storage.UpdateUser(testUser);
var changedUser = storage.GetUsersList().FirstOrDefault(x => x.Id == testedUserdId);
Assert.True(result);
Assert.NotNull(changedUser);
Assert.Equal(changedUser.FirstName, testedFirstName);
}