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POWhy does this Rails association shortcut fail? What is the correct way?
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  1. POWhy does this Rails association shortcut fail? What is the correct way?
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    copied!<p>In the given case a User may:</p> <ul> <li><strong>invite many invitees</strong> (has_many :invitations)</li> <li><strong>accept one invitation</strong> (has_one :invitation)</li> </ul> <p>According to <a href="http://guides.rubyonrails.org/association_basics.html#the-has_many-through-association" rel="nofollow">http://guides.rubyonrails.org/association_basics.html#the-has_many-through-association</a> a <strong>has_many :through</strong> association should allow me to use a shortcut like the one in the following functional test.</p> <p>However, it fails with the error noted in the comment.</p> <p><strong>snippet from functional test:</strong></p> <pre><code>assert_difference('Invitation.count') do # WORKS post :create, :user =&gt; { :email =&gt; invitee_email, :password =&gt; "1password" } end @invitee = User.find_by_email(invitee_email) @invitation = Invitation.find_by_issuer_id_and_invitee_id(@issuer.id, @invitee.id) assert @invitation.valid? # WORKS assert_present @invitation.issuer # WORKS assert_present @invitation.invitee # WORKS # TODO: repair assert_present @issuer.invitees # FAILS with "[] is blank" assert_present @invitee.issuer # FAILS with "nil is blank" </code></pre> <p><strong>snippet from the method under test:</strong></p> <pre><code>@issuer.create_invitation(:invitee =&gt; @invitee, :accepted_at =&gt; Time.now) # tested as well - also fails the test: # Invitation.create!(:issuer =&gt; @issuer, :invitee =&gt; @invitee, :accepted_at =&gt; Time.now) </code></pre> <p><strong>relevant parts of invitation.rb:</strong></p> <pre><code>belongs_to :issuer, :class_name =&gt; "User" belongs_to :invitee, :class_name =&gt; "User" validates_presence_of :issuer validates_presence_of :invitee </code></pre> <p><strong>relevant parts of user.rb:</strong></p> <pre><code>has_many :invitations, :foreign_key =&gt; 'invitee_id', :dependent =&gt; :destroy has_many :invitees, :through =&gt; :invitations has_one :invitation, :foreign_key =&gt; 'issuer_id', :dependent =&gt; :destroy has_one :issuer, :through =&gt; :invitation </code></pre> <p>Now I wonder:</p> <ul> <li><strong>What is the correct 'shortcut'?</strong></li> <li><strong>Are my models set up correctly in the first place?</strong></li> </ul>
 

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