AO3-3997 Add missing error message in invitation page

app/views/invitations/_invitation.html.erb

@@ -10,8 +10,9 @@
     <dd><%= invitation.invitee_email %></dd>
     <% else %>
     <dd>
+      <%= error_messages_for @invitation %>
       <%= form_for(invitation) do |f| %>
-        <p><label for="invitee_email">Enter an email address:</label> <%= f.text_field :invitee_email %></p>
+        <p><%= label_tag "invitation[invitee_email]", t('.email_address_label') %>: <%= f.text_field :invitee_email %></p>
         <p><%= hidden_field_tag :user_id, @user.try(:login) %></p>
         <p class="submit actions"><%= f.submit %></p>
       <% end %>

config/locales/views/en.yml

@@ -428,6 +428,9 @@ en:
   home:
     donate:
       page_title: Donate or Volunteer
+  invitations:
+    invitation:
+      email_address_label: Enter an email address
   invite_requests:
     invite_request:
       date: 'At our current rate, you should receive an invitation on or around: %{date}.'

features/other_a/invite_request.feature

@@ -62,6 +62,18 @@ Feature: Invite requests
       And I should not see "Sorry, you have no unsent invitations right now."
       And I should see "You have 2 open invitations and 0 that have been sent but not yet used."
 
+  Scenario: User can fail to send an invitation to an invalid email address
+
+    Given invitations are required
+      And I am logged in as "user1"
+      And I request some invites
+      And an admin grants the request
+      And I try to invite a friend from my user page
+    When all emails have been delivered
+      And I fill in "invitation[invitee_email]" with "test@"
+      And I press "Send Invitation"
+    Then I should see "Invitee email should look like an email address"
+
   Scenario: User can send out invites they have been granted, and the recipient can sign up
 
     Given invitations are required