1 files changed, 57 insertions, 0 deletions
diff --git a/activemodel/test/cases/type/decimal_test.rb b/activemodel/test/cases/type/decimal_test.rb
new file mode 100644
index 0000000000..353dbf84ad
--- /dev/null
+++ b/activemodel/test/cases/type/decimal_test.rb
@@ -0,0 +1,57 @@
+require "cases/helper"
+require "active_model/type"
+
+module ActiveModel
+  module Type
+    class DecimalTest < ActiveModel::TestCase
+      def test_type_cast_decimal
+        type = Decimal.new
+        assert_equal BigDecimal.new("0"), type.cast(BigDecimal.new("0"))
+        assert_equal BigDecimal.new("123"), type.cast(123.0)
+        assert_equal BigDecimal.new("1"), type.cast(:"1")
+      end
+
+      def test_type_cast_decimal_from_float_with_large_precision
+        type = Decimal.new(precision: ::Float::DIG + 2)
+        assert_equal BigDecimal.new("123.0"), type.cast(123.0)
+      end
+
+      def test_type_cast_from_float_with_unspecified_precision
+        type = Decimal.new
+        assert_equal 22.68.to_d, type.cast(22.68)
+      end
+
+      def test_type_cast_decimal_from_rational_with_precision
+        type = Decimal.new(precision: 2)
+        assert_equal BigDecimal("0.33"), type.cast(Rational(1, 3))
+      end
+
+      def test_type_cast_decimal_from_rational_with_precision_and_scale
+        type = Decimal.new(precision: 4, scale: 2)
+        assert_equal BigDecimal("0.33"), type.cast(Rational(1, 3))
+      end
+
+      def test_type_cast_decimal_from_rational_without_precision_defaults_to_18_36
+        type = Decimal.new
+        assert_equal BigDecimal("0.333333333333333333E0"), type.cast(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.cast(value)
+      end
+
+      def test_changed?
+        type = Decimal.new
+
+        assert type.changed?(5.0, 5.0, '5.0wibble')
+        assert_not type.changed?(5.0, 5.0, '5.0')
+        assert_not type.changed?(-5.0, -5.0, '-5.0')
+      end
+    end
+  end
+end