Move the appropriate type tests to the Active Model suite

Any tests for a type which is not overridden by Active Record, and does
not test the specifics of the attributes API interacting in more complex
ways have no reason to be in the Active Record suite. Doing this
revealed that the implementation of the date and time types in AM was
actually completely broken, and incapable of returning any value other
than `nil`.

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