1 files changed, 43 insertions, 0 deletions
diff --git a/activemodel/test/cases/errors_test.rb b/activemodel/test/cases/errors_test.rb
index 784a2b2709..8ddedb160a 100644
--- a/activemodel/test/cases/errors_test.rb
+++ b/activemodel/test/cases/errors_test.rb
@@ -80,6 +80,49 @@ class ErrorsTest < ActiveModel::TestCase
     assert_equal ["can not be blank"], person.errors[:name]
   end
 
+  test "added? should be true if that error was added" do
+    person = Person.new
+    person.errors.add(:name, "can not be blank")
+    assert person.errors.added?(:name, "can not be blank")
+  end
+
+  test "added? should handle when message is a symbol" do
+    person = Person.new
+    person.errors.add(:name, :blank)
+    assert person.errors.added?(:name, :blank)
+  end
+
+  test "added? should handle when message is a proc" do
+    person = Person.new
+    message = Proc.new { "can not be blank" }
+    person.errors.add(:name, message)
+    assert person.errors.added?(:name, message)
+  end
+
+  test "added? should default message to :invalid" do
+    person = Person.new
+    person.errors.add(:name, :invalid)
+    assert person.errors.added?(:name)
+  end
+
+  test "added? should be true when several errors are present, and we ask for one of them" do
+    person = Person.new
+    person.errors.add(:name, "can not be blank")
+    person.errors.add(:name, "is invalid")
+    assert person.errors.added?(:name, "can not be blank")
+  end
+
+  test "added? should be false if no errors are present" do
+    person = Person.new
+    assert !person.errors.added?(:name)
+  end
+
+  test "added? should be false when an error is present, but we check for another error" do
+    person = Person.new
+    person.errors.add(:name, "is invalid")
+    assert !person.errors.added?(:name, "can not be blank")
+  end
+
   test 'should respond to size' do
     person = Person.new
     person.errors.add(:name, "can not be blank")