Change Numericaly validator to use round

f72f743 introduces truncate(scale) in the Numericality validator.
This behaviour conflicts with AR decimal type conversion,
which uses round(scale) instead.

Changes the Numericality validator in order to use
round(scale) for consistency.

activemodel/lib/active_model/validations/numericality.rb

@@ -71,6 +71,8 @@ module ActiveModel
           raw_value if raw_value.is_a?(Range)
         elsif raw_value.is_a?(Float)
           parse_float(raw_value, precision, scale)
+        elsif raw_value.is_a?(BigDecimal)
+          round(raw_value, scale)
         elsif raw_value.is_a?(Numeric)
           raw_value
         elsif is_integer?(raw_value)
@@ -81,7 +83,11 @@ module ActiveModel
       end
 
       def parse_float(raw_value, precision, scale)
-        (scale ? raw_value.truncate(scale) : raw_value).to_d(precision)
+        round(raw_value, scale).to_d(precision)
+      end
+
+      def round(raw_value, scale)
+        scale ? raw_value.round(scale) : raw_value
       end
 
       def is_number?(raw_value, precision, scale)

activerecord/test/cases/validations/numericality_validation_test.rb

@@ -103,6 +103,21 @@ class NumericalityValidationTest < ActiveRecord::TestCase
     assert_not_predicate subject, :valid?
   end
 
+  def test_virtual_attribute_with_precision_and_scale
+    model_class.attribute(:virtual_decimal_number, :decimal, precision: 4, scale: 2)
+    model_class.validates_numericality_of(
+      :virtual_decimal_number, less_than_or_equal_to: 99.99
+    )
+
+    subject = model_class.new(virtual_decimal_number: 99.994)
+    assert_equal 99.99.to_d(4), subject.virtual_decimal_number
+    assert_predicate subject, :valid?
+
+    subject = model_class.new(virtual_decimal_number: 99.999)
+    assert_equal 100.00.to_d(4), subject.virtual_decimal_number
+    assert_not_predicate subject, :valid?
+  end
+
   def test_aliased_attribute
     model_class.validates_numericality_of(:new_bank_balance, greater_or_equal_than: 0)
 

activerecord/test/cases/validations_test.rb

@@ -187,9 +187,17 @@ class ValidationsTest < ActiveRecord::TestCase
       validates_numericality_of :wibble, greater_than_or_equal_to: BigDecimal("97.18")
     end
 
-    assert_not_predicate klass.new(wibble: "97.179"), :valid?
-    assert_not_predicate klass.new(wibble: 97.179), :valid?
-    assert_not_predicate klass.new(wibble: BigDecimal("97.179")), :valid?
+    ["97.179", 97.179, BigDecimal("97.179")].each do |raw_value|
+      subject = klass.new(wibble: raw_value)
+      assert_equal 97.18.to_d(4), subject.wibble
+      assert_predicate subject, :valid?
+    end
+
+    ["97.174", 97.174, BigDecimal("97.174")].each do |raw_value|
+      subject = klass.new(wibble: raw_value)
+      assert_equal 97.17.to_d(4), subject.wibble
+      assert_not_predicate subject, :valid?
+    end
   end
 
   def test_numericality_validator_wont_be_affected_by_custom_getter