Introduce an object to aid in creation and management of `@attributes`

Mostly delegation to start, but we can start moving a lot of behavior in
bulk to this object.

1 files changed, 49 insertions, 0 deletions

diff --git a/activerecord/test/cases/attribute_set_test.rb b/activerecord/test/cases/attribute_set_test.rb
new file mode 100644
index 0000000000..091f7e396a
--- /dev/null
+++ b/activerecord/test/cases/attribute_set_test.rb
@@ -0,0 +1,49 @@
+require 'cases/helper'
+
+module ActiveRecord
+  class AttributeSetTest < ActiveRecord::TestCase
+    test "building a new set from raw attributes" do
+      builder = AttributeSet::Builder.new(foo: Type::Integer.new, bar: Type::Float.new)
+      attributes = builder.build_from_database(foo: '1.1', bar: '2.2')
+
+      assert_equal 1, attributes[:foo].value
+      assert_equal 2.2, attributes[:bar].value
+    end
+
+    test "building with custom types" do
+      builder = AttributeSet::Builder.new(foo: Type::Float.new)
+      attributes = builder.build_from_database({ foo: '3.3', bar: '4.4' }, { bar: Type::Integer.new })
+
+      assert_equal 3.3, attributes[:foo].value
+      assert_equal 4, attributes[:bar].value
+    end
+
+    test "duping creates a new hash and dups each attribute" do
+      builder = AttributeSet::Builder.new(foo: Type::Integer.new, bar: Type::String.new)
+      attributes = builder.build_from_database(foo: 1, bar: 'foo')
+
+      # Ensure the type cast value is cached
+      attributes[:foo].value
+      attributes[:bar].value
+
+      duped = attributes.dup
+      duped[:foo] = Attribute.from_database(2, Type::Integer.new)
+      duped[:bar].value << 'bar'
+
+      assert_equal 1, attributes[:foo].value
+      assert_equal 2, duped[:foo].value
+      assert_equal 'foo', attributes[:bar].value
+      assert_equal 'foobar', duped[:bar].value
+    end
+
+    test "freezing cloned set does not freeze original" do
+      attributes = AttributeSet.new({})
+      clone = attributes.clone
+
+      clone.freeze
+
+      assert clone.frozen?
+      assert_not attributes.frozen?
+    end
+  end
+end