Add failing test for ActiveModel::Errors#has_key? method

From the doc, this method should return false and not nil if there is no errors for this key

1 files changed, 5 insertions, 0 deletions

diff --git a/activemodel/test/cases/errors_test.rb b/activemodel/test/cases/errors_test.rb
index bbd186d83d..481f274936 100644
--- a/activemodel/test/cases/errors_test.rb
+++ b/activemodel/test/cases/errors_test.rb
@@ -54,6 +54,11 @@ class ErrorsTest < ActiveModel::TestCase
     assert errors.has_key?(:foo), 'errors should have key :foo'
   end
 
+  def test_has_no_key
+    errors = ActiveModel::Errors.new(self)
+    assert_equal false, errors.has_key?(:name), 'errors should not have key :name'
+  end
+
   test "clear errors" do
     person = Person.new
     person.validate!