Fixed the tests and apart from one, they all work

test/controllers/credentials_controller_test.rb

@@ -5,7 +5,7 @@ class CredentialsControllerTest < ActionDispatch::IntegrationTest
 
   setup do
     @credential = credentials(:one)
-    @domain = domains(:one)
+    @domain = domains(:domainone)
   end
 
   test "should not get new" do

test/controllers/domains_controller_test.rb

@@ -3,7 +3,7 @@ require "test_helper"
 class DomainsControllerTest < ActionDispatch::IntegrationTest
   include Devise::Test::IntegrationHelpers
   setup do
-    @domain = domains(:one)
+    @domain = domains(:domainone)
   end
 
   test "not should get index because user not logged in" do

test/controllers/virtuals_controller_test.rb

@@ -5,7 +5,7 @@ class VirtualsControllerTest < ActionDispatch::IntegrationTest
 
   setup do
     @virtual = virtuals(:one)
-    @domain = domains(:one)
+    @domain = domains(:domainone)
   end
 
   test "should get not get new because we are not logged in" do

test/models/credential_test.rb

@@ -19,7 +19,12 @@ class CredentialTest < ActiveSupport::TestCase
   end
 
   test "domain added to name" do
-    @c = Credential.new(email: "jez@#{domains(:one).domain}", password: "1234567&ab", domain_id: domains(:one).id)
+    @c = Credential.new(email: "jez@#{domains(:domainone).domain}", password: "1234567&ab", domain_id: domains(:domainone).id)
     assert @c.save
   end
+
+  test "domain_id not the same as domain" do
+    @c = Credential.new(email: "steve@#{domains(:domainone).domain}", password: "1234567&ab", domain_id: domains(:domainone).id)
+    assert_not @c.save
+  end
 end

test/models/virtual_test.rb

@@ -43,7 +43,7 @@ class VirtualTest < ActiveSupport::TestCase
     @v = Virtual.new
     @v.email = "abuse@example.net"
     @v.destination = "valid@email.com"
-    @v.domain_id = domains(:one).id + 1234
+    @v.domain_id = domains(:domainone).id + 1234
     assert !@v.save
   end