Fix decimal_test module and add new test for object responding to to_d

activerecord/lib/active_record/type/decimal.rb

@@ -23,7 +23,6 @@ module ActiveRecord
           cast_value(value.to_s)
         end
       end
-
     end
   end
 end

activerecord/test/cases/type/decimal_test.rb

@@ -1,24 +1,33 @@
 require "cases/helper"
 
 module ActiveRecord
-  module ConnectionAdapters
+  module Type
     class DecimalTest < ActiveRecord::TestCase
       def test_type_cast_decimal
-        type = Type::Decimal.new
+        type = Decimal.new
         assert_equal BigDecimal.new("0"), type.type_cast_from_user(BigDecimal.new("0"))
         assert_equal BigDecimal.new("123"), type.type_cast_from_user(123.0)
         assert_equal BigDecimal.new("1"), type.type_cast_from_user(:"1")
       end
 
-      def test_type_cast_rational_to_decimal_with_precision
-        type = Type::Decimal.new(precision: 2)
+      def test_type_cast_decimal_from_rational_with_precision
+        type = Decimal.new(precision: 2)
         assert_equal BigDecimal("0.33"), type.type_cast_from_user(Rational(1, 3))
       end
 
-      def test_type_cast_rational_to_decimal_without_precision_defaults_to_18_36
-        type = Type::Decimal.new
+      def test_type_cast_decimal_from_rational_without_precision_defaults_to_18_36
+        type = Decimal.new
         assert_equal BigDecimal("0.333333333333333333E0"), type.type_cast_from_user(Rational(1, 3))
       end
+
+      def test_type_cast_decimal_from_object_responding_to_d
+        value = Object.new
+        def value.to_d
+          BigDecimal.new("1")
+        end
+        type = Decimal.new
+        assert_equal BigDecimal("1"), type.type_cast_from_user(value)
+      end
     end
   end
 end