Rspec Rails - Name should be valid - some clarifications - ruby-on-rails

Question

i'm into rspec these days, trying to make my models more precise and accurate. Some things are still a bit weird to me about rspec and so i thought it would be nice if someone could clarify.
Let's say that i have a User model. This one has a :name. The name should be between 4..15 characters(that's a secondary objective, at first it must just exist). So now i'm thinking: What is the best way to test that in a manner that assures that this will happen. To test that a user must have a name, i wrote something like this :
describe User do
let(:user) { User.new(:name => 'lele') }
it "is not valid without a name" do
user.name.should == 'lele'
end
end
Now, i'm not quite sure that this accomplishes exactly what i want. It seems to me that i'm actually testing Rails with this one. Moreover, if i want to check that a name cannot be more than 15 chars and less than 4, how can this be integrated ?
EDIT:
Maybe this is better ?
describe User do
let(:user) { User.new(:name => 'lele') }
it "is not valid without a name" do
user.name.should_not be_empty
end
end

Answer 1

You're probably looking for the be_valid matcher:
describe User do
let(:user) { User.new(:name => 'lele') }
it "is valid with a name" do
user.should be_valid
end
it "is not valid without a name" do
user.name = nil
user.should_not be_valid
end
end

Answer 2

I use this way:
describe User do
it "should have name" do
lambda{User.create! :name => nil}.should raise_error
end
it "is not valid when the name is longer than 15 characters" do
lambda{User.create! :name => "im a very looooooooong name"}.should raise_error
end
it "is not valid when the name is shorter than 4 characters" do
lambda{User.create! :name => "Tom"}.should raise_error
end
end

Answer 3

I like to test the actual error messages for validations:
require 'spec_helper'
describe User do
let (:user) { User.new }
it "is invalid without a name" do
user.valid?
user.errors[:name].should include("can't be blank")
end
it "is invalid when less than 4 characters" do
user.name = "Foo"
user.valid?
user.errors[:name].should include("is too short (minimum is 4 characters)")
end
it "is invalid when greater than 15 characters" do
user.name = "A very, very, very long name"
user.valid?
user.errors[:name].should include("is too long (maximum is 15 characters)")
end
end
It's also helpful to use a factory that builds an object with valid attributes, which you can invalidate one at a time for testing.

Answer 4

I would use something similar to this
class User < ActiveRecord::Base
validates_presence_of :name
validates_length_of :name, :in => 4..15
end
describe User do
it "validates presence of name" do
user = User.new
user.valid?.should be_false
user.name = "valid name"
user.valid?.should be_true
end
it "validates length of name in 4..15" do
user = User.new
user.name = "123"
user.valid?.should be_false
user.name = "1234567890123456"
user.valid?.should be_false
user.name = "valid name"
user.valid?.should be_true
end
end
Most notable is that I'm using active record validations for both conditions. In my examples I don't rely on the error strings. In examples that test the behavior of validations there's no reason to touch the database so I don't. In each example I test the behavior of the object when it's both valid and invalid.