Question

Currently i am learning with the youtube video Efficient Rails Test Driven Development – by Wolfram Arnold
One exercise is:

A Person object has an optional middle_name.

I create a migration to add the middle name to the database

• rake g migration AddMiddleNameToPerson middle_name:string

and i write a spec

it “can have a middle name”

But i got no idea how to test this issue
how can i test an optional field

thanks for help

Bulleric

Answer 1

To say that an attribute is ‘optional’ implies that the instance is valid when the attribute is nil. So:

it "does not require a middle name" do
  @person = Person.new
  @person.valid?
  @person.errors[:middle_name].should_not include("can't be blank")
end

If you’re using shoulda then this can be made even simpler:

describe Person do
  it { should_not validate_presence_of(:middle_name) }
end