1 files changed, 52 insertions, 12 deletions
diff --git a/activerecord/test/cases/serialized_attribute_test.rb b/activerecord/test/cases/serialized_attribute_test.rb
index f8d87a3661..6056156698 100644
--- a/activerecord/test/cases/serialized_attribute_test.rb
+++ b/activerecord/test/cases/serialized_attribute_test.rb
@@ -16,18 +16,12 @@ class SerializedAttributeTest < ActiveRecord::TestCase
   end
 
   def test_serialize_does_not_eagerly_load_columns
+    Topic.reset_column_information
     assert_no_queries do
-      Topic.reset_column_information
       Topic.serialize(:content)
     end
   end
 
-  def test_list_of_serialized_attributes
-    assert_deprecated do
-      assert_equal %w(content), Topic.serialized_attributes.keys
-    end
-  end
-
   def test_serialized_attribute
     Topic.serialize("content", MyObject)
 
@@ -140,11 +134,10 @@ class SerializedAttributeTest < ActiveRecord::TestCase
     assert_equal 1, Topic.where(:content => nil).count
   end
 
-  def test_serialized_attribute_should_raise_exception_on_save_with_wrong_type
+  def test_serialized_attribute_should_raise_exception_on_assignment_with_wrong_type
     Topic.serialize(:content, Hash)
     assert_raise(ActiveRecord::SerializationTypeMismatch) do
-      topic = Topic.new(content: 'string')
-      topic.save
+      Topic.new(content: 'string')
     end
   end
 
@@ -244,8 +237,9 @@ class SerializedAttributeTest < ActiveRecord::TestCase
     t = Topic.create(content: "first")
     assert_equal("first", t.content)
 
-    t.update_column(:content, Topic.type_for_attribute('content').type_cast_for_database("second"))
-    assert_equal("second", t.content)
+    t.update_column(:content, ["second"])
+    assert_equal(["second"], t.content)
+    assert_equal(["second"], t.reload.content)
   end
 
   def test_serialized_column_should_unserialize_after_update_attribute
@@ -254,5 +248,51 @@ class SerializedAttributeTest < ActiveRecord::TestCase
 
     t.update_attribute(:content, "second")
     assert_equal("second", t.content)
+    assert_equal("second", t.reload.content)
+  end
+
+  def test_nil_is_not_changed_when_serialized_with_a_class
+    Topic.serialize(:content, Array)
+
+    topic = Topic.new(content: nil)
+
+    assert_not topic.content_changed?
+  end
+
+  def test_classes_without_no_arg_constructors_are_not_supported
+    assert_raises(ArgumentError) do
+      Topic.serialize(:content, Regexp)
+    end
+  end
+
+  def test_newly_emptied_serialized_hash_is_changed
+    Topic.serialize(:content, Hash)
+    topic = Topic.create(content: { "things" => "stuff" })
+    topic.content.delete("things")
+    topic.save!
+    topic.reload
+
+    assert_equal({}, topic.content)
+  end
+
+  def test_values_cast_from_nil_are_persisted_as_nil
+    # This is required to fulfil the following contract, which must be universally
+    # true in Active Record:
+    #
+    # model.attribute = value
+    # assert_equal model.attribute, model.tap(&:save).reload.attribute
+    Topic.serialize(:content, Hash)
+    topic = Topic.create!(content: {})
+    topic2 = Topic.create!(content: nil)
+
+    assert_equal [topic, topic2], Topic.where(content: nil)
+  end
+
+  def test_nil_is_always_persisted_as_null
+    Topic.serialize(:content, Hash)
+
+    topic = Topic.create!(content: { foo: "bar" })
+    topic.update_attribute :content, nil
+    assert_equal [topic], Topic.where(content: nil)
   end
 end