diff --git a/test/models/api_user_test.rb b/test/models/api_user_test.rb
index 525e6c264..ec53d2371 100644
--- a/test/models/api_user_test.rb
+++ b/test/models/api_user_test.rb
@@ -22,9 +22,26 @@ class ApiUserTest < ActiveSupport::TestCase
     assert another_user.invalid?
 
     another_user.username = 'another'
+    another_user.identity_code = ''
     assert another_user.valid?
   end
 
+  def test_invalid_when_one_registrar_and_identity_code_is_already_taken
+    user = valid_user
+    another_user = user.dup
+
+    assert another_user.invalid?
+
+    another_user.username = 'another'
+    assert another_user.invalid?
+  end
+
+  def test_valid_when_another_registrar_and_identity_code_is_already_taken
+    another_user = valid_user
+    @user.identity_code = another_user.identity_code
+    assert @user.valid?
+  end
+
   def test_invalid_without_password
     user = valid_user
     user.plain_text_password = ''