Rspec单元测试由于先前的测试而失败

Question

I'm new to Rspec and I'm putting in tests for an old project. I'm having issues with setting variables. Bascially my User object is affected by actions in previous tests. I have a simple user factory:

FactoryGirl.define do
    factory :user do
        first_name 'Bob'
        last_name 'Shabbadoo'
        office
        login 'lurker48'
        email 'test.user@test.com'
        password 'TestWhatNots#21'
        password_confirmation{|u| u.password}
    end
end

Then I have my actual rspec tests.

require "spec_helper"

describe User do

    it 'has a valid factory' do
        FactoryGirl.build(:user).should be_valid
    end

  describe '#password' do

    it "cannot contain the word 'password'" do
        valid_user = FactoryGirl.build(:user)
        valid_user.password << "password"
        valid_user.password_confirmation = valid_user.password
        valid_user.should_not be_valid
    end

    it "cannot contain the users last_name" do
        valid_user = FactoryGirl.build(:user)
        valid_user.password << valid_user.last_name
        valid_user.password_confirmation = valid_user.password
        valid_user.should_not be_valid
    end

    it "cannot contain the users first_name" do
        valid_user = FactoryGirl.build(:user)
        valid_user.password << valid_user.first_name
        valid_user.password_confirmation = valid_user.password
        valid_user.should be_valid
    end
  end

end

I purposefully made the "cannot contain the users first_name" test fail and as I expected I got this:

User
  has a valid factory
  #password
    cannot contain the word 'password'
    cannot contain the users last_name
    cannot contain the users first_name (FAILED - 1)

But when I took a closer look a the password it looked like this:

TestWhatNots#21passwordShabbadooBob

Why would actions in previous tests taint the information?

Answer 1

When you build new user object, factory girl assigns to its password given string (it is, to the instance of String class). Every time you do this, you user password is pointing to that object - if you build two users, their password are not only identical - the are the same object.

By using << method youre altering this object and hence you are altering password value for all objects which have been or will be created by this factory.

 u1 = FactoryGirl.build(:user)
 u2 = FactoryGirl.build(:user)

 u1.password.object_id == u2.password.object_id   #=> true!

Solutions:

Option 1. Do not modify the object but assign a new string object instead:

valid_user.password += valid_user.first_name

Option 2. Wrap all your values within a block. This will force FactoryGirl to run block each time you build new object and hence to create separate but identical String instances:

factory :user do
    first_name { 'Bob' }
    last_name { 'Shabbadoo' }
    ...