Support configuration on ActiveRecord::Model.

The problem: We need to be able to specify configuration in a way that
can be inherited to models that include ActiveRecord::Model. So it is
no longer sufficient to put 'top level' config on ActiveRecord::Base,
but we do want configuration specified on ActiveRecord::Base and
descendants to continue to work.

So we need something like class_attribute that can be defined on a
module but that is inherited when ActiveRecord::Model is included.

The solution: added ActiveModel::Configuration module which provides a
config_attribute macro. It's a bit specific hence I am not putting this
in Active Support or making it a 'public API' at present.

1 files changed, 154 insertions, 0 deletions

diff --git a/activemodel/test/cases/configuration_test.rb b/activemodel/test/cases/configuration_test.rb
new file mode 100644
index 0000000000..a172fa26a3
--- /dev/null
+++ b/activemodel/test/cases/configuration_test.rb
@@ -0,0 +1,154 @@
+require 'cases/helper'
+
+class ConfigurationOnModuleTest < ActiveModel::TestCase
+  def setup
+    @mod = mod = Module.new do
+      extend ActiveSupport::Concern
+      extend ActiveModel::Configuration
+
+      config_attribute :omg
+      self.omg = "default"
+
+      config_attribute :wtf, global: true
+      self.wtf = "default"
+
+      config_attribute :boolean
+
+      config_attribute :lol, instance_writer: true
+    end
+
+    @klass = Class.new do
+      include mod
+    end
+
+    @subklass = Class.new(@klass)
+  end
+
+  test "default" do
+    assert_equal "default", @mod.omg
+    assert_equal "default", @klass.omg
+    assert_equal "default", @klass.new.omg
+  end
+
+  test "setting" do
+    @mod.omg = "lol"
+    assert_equal "lol", @mod.omg
+  end
+
+  test "setting on class including the module" do
+    @klass.omg = "lol"
+    assert_equal "lol", @klass.omg
+    assert_equal "lol", @klass.new.omg
+    assert_equal "default", @mod.omg
+  end
+
+  test "setting on subclass of class including the module" do
+    @subklass.omg = "lol"
+    assert_equal "lol", @subklass.omg
+    assert_equal "default", @klass.omg
+    assert_equal "default", @mod.omg
+  end
+
+  test "setting on instance" do
+    assert !@klass.new.respond_to?(:omg=)
+
+    @klass.lol = "lol"
+    obj = @klass.new
+    assert_equal "lol", obj.lol
+    obj.lol = "omg"
+    assert_equal "omg", obj.lol
+    assert_equal "lol", @klass.lol
+    assert_equal "lol", @klass.new.lol
+    obj.lol = false
+    assert !obj.lol?
+  end
+
+  test "global attribute" do
+    assert_equal "default", @mod.wtf
+    assert_equal "default", @klass.wtf
+
+    @mod.wtf = "wtf"
+
+    assert_equal "wtf", @mod.wtf
+    assert_equal "wtf", @klass.wtf
+
+    @klass.wtf = "lol"
+
+    assert_equal "lol", @mod.wtf
+    assert_equal "lol", @klass.wtf
+  end
+
+  test "boolean" do
+    assert_equal false, @mod.boolean?
+    assert_equal false, @klass.new.boolean?
+    @mod.boolean = true
+    assert_equal true, @mod.boolean?
+    assert_equal true, @klass.new.boolean?
+  end
+end
+
+class ConfigurationOnClassTest < ActiveModel::TestCase
+  def setup
+    @klass = Class.new do
+      extend ActiveModel::Configuration
+
+      config_attribute :omg
+      self.omg = "default"
+
+      config_attribute :wtf, global: true
+      self.wtf = "default"
+
+      config_attribute :omg2, instance_writer: true
+      config_attribute :wtf2, instance_writer: true, global: true
+    end
+
+    @subklass = Class.new(@klass)
+  end
+
+  test "defaults" do
+    assert_equal "default", @klass.omg
+    assert_equal "default", @klass.wtf
+    assert_equal "default", @subklass.omg
+    assert_equal "default", @subklass.wtf
+  end
+
+  test "changing" do
+    @klass.omg = "lol"
+    assert_equal "lol", @klass.omg
+    assert_equal "lol", @subklass.omg
+  end
+
+  test "changing in subclass" do
+    @subklass.omg = "lol"
+    assert_equal "lol", @subklass.omg
+    assert_equal "default", @klass.omg
+  end
+
+  test "changing global" do
+    @klass.wtf = "wtf"
+    assert_equal "wtf", @klass.wtf
+    assert_equal "wtf", @subklass.wtf
+
+    @subklass.wtf = "lol"
+    assert_equal "lol", @klass.wtf
+    assert_equal "lol", @subklass.wtf
+  end
+
+  test "instance_writer" do
+    obj = @klass.new
+
+    @klass.omg2 = "omg"
+    @klass.wtf2 = "wtf"
+
+    assert_equal "omg", obj.omg2
+    assert_equal "wtf", obj.wtf2
+
+    obj.omg2 = "lol"
+    obj.wtf2 = "lol"
+
+    assert_equal "lol", obj.omg2
+    assert_equal "lol", obj.wtf2
+    assert_equal "omg", @klass.omg2
+    assert_equal "lol", @klass.wtf2
+  end
+end