Adds/Corrects use case for adding an error message

I believe this is a use case that was supposed to be supported, and it's
a small fix.

1 files changed, 6 insertions, 0 deletions

diff --git a/activemodel/test/cases/errors_test.rb b/activemodel/test/cases/errors_test.rb
index f781a0017f..d10c20caad 100644
--- a/activemodel/test/cases/errors_test.rb
+++ b/activemodel/test/cases/errors_test.rb
@@ -149,6 +149,12 @@ class ErrorsTest < ActiveModel::TestCase
     assert_equal ["cannot be blank"], person.errors[:name]
   end
 
+  test "add an error message on a specific attribute with a defined type" do
+    person = Person.new
+    person.errors.add(:name, :blank, message: "cannot be blank")
+    assert_equal ["cannot be blank"], person.errors[:name]
+  end
+
   test "add an error with a symbol" do
     person = Person.new
     person.errors.add(:name, :blank)