Allow `serialize` with a custom coder on `json` and `array` columns

We already have a test case for `serialize` with a custom coder in
`PostgresqlHstoreTest`.

https://github.com/rails/rails/blob/v5.1.3/activerecord/test/cases/adapters/postgresql/hstore_test.rb#L316-L335

1 files changed, 25 insertions, 1 deletions

diff --git a/activerecord/test/cases/adapters/postgresql/array_test.rb b/activerecord/test/cases/adapters/postgresql/array_test.rb
index 08b17f37e2..0e9e86f425 100644
--- a/activerecord/test/cases/adapters/postgresql/array_test.rb
+++ b/activerecord/test/cases/adapters/postgresql/array_test.rb
@@ -47,7 +47,7 @@ class PostgresqlArrayTest < ActiveRecord::PostgreSQLTestCase
     assert ratings_column.array?
   end
 
-  def test_not_compatible_with_serialize
+  def test_not_compatible_with_serialize_array
     new_klass = Class.new(PgArray) do
       serialize :tags, Array
     end
@@ -56,6 +56,30 @@ class PostgresqlArrayTest < ActiveRecord::PostgreSQLTestCase
     end
   end
 
+  class MyTags
+    def initialize(tags); @tags = tags end
+    def to_a; @tags end
+    def self.load(tags); new(tags) end
+    def self.dump(object); object.to_a end
+  end
+
+  def test_array_with_serialized_attributes
+    new_klass = Class.new(PgArray) do
+      serialize :tags, MyTags
+    end
+
+    new_klass.create!(tags: MyTags.new(["one", "two"]))
+    record = new_klass.first
+
+    assert_instance_of MyTags, record.tags
+    assert_equal ["one", "two"], record.tags.to_a
+
+    record.tags = MyTags.new(["three", "four"])
+    record.save!
+
+    assert_equal ["three", "four"], record.reload.tags.to_a
+  end
+
   def test_default
     @connection.add_column "pg_arrays", "score", :integer, array: true, default: [4, 4, 2]
     PgArray.reset_column_information