3 files changed, 12 insertions, 10 deletions
diff --git a/activemodel/lib/active_model/type/decimal.rb b/activemodel/lib/active_model/type/decimal.rb
index 6c5c0451c6..541a12c8a1 100644
--- a/activemodel/lib/active_model/type/decimal.rb
+++ b/activemodel/lib/active_model/type/decimal.rb
@@ -4,6 +4,7 @@ module ActiveModel
   module Type
     class Decimal < Value # :nodoc:
       include Helpers::Numeric
+      BIGDECIMAL_PRECISION = 18
 
       def type
         :decimal
@@ -21,7 +22,7 @@ module ActiveModel
             when ::Float
               convert_float_to_big_decimal(value)
             when ::Numeric, ::String
-              BigDecimal(value, precision.to_i)
+              BigDecimal(value, precision || BIGDECIMAL_PRECISION)
             else
               if value.respond_to?(:to_d)
                 value.to_d
diff --git a/activemodel/test/cases/errors_test.rb b/activemodel/test/cases/errors_test.rb
index e6ba06301d..0872084cf5 100644
--- a/activemodel/test/cases/errors_test.rb
+++ b/activemodel/test/cases/errors_test.rb
@@ -1,4 +1,5 @@
 require "cases/helper"
+require "active_support/core_ext/string/strip"
 require "yaml"
 
 class ErrorsTest < ActiveModel::TestCase
diff --git a/activemodel/test/cases/helper.rb b/activemodel/test/cases/helper.rb
index 4e9f43ad86..40dfb8e589 100644
--- a/activemodel/test/cases/helper.rb
+++ b/activemodel/test/cases/helper.rb
@@ -9,15 +9,15 @@ I18n.enforce_available_locales = false
 require "active_support/testing/autorun"
 require "active_support/testing/method_call_assertions"
 
-# Skips the current run on Rubinius using Minitest::Assertions#skip
-def rubinius_skip(message = "")
-  skip message if RUBY_ENGINE == "rbx"
-end
-# Skips the current run on JRuby using Minitest::Assertions#skip
-def jruby_skip(message = "")
-  skip message if defined?(JRUBY_VERSION)
-end
-
 class ActiveModel::TestCase
   include ActiveSupport::Testing::MethodCallAssertions
+
+  # Skips the current run on Rubinius using Minitest::Assertions#skip
+  private def rubinius_skip(message = "")
+    skip message if RUBY_ENGINE == "rbx"
+  end
+  # Skips the current run on JRuby using Minitest::Assertions#skip
+  private def jruby_skip(message = "")
+    skip message if defined?(JRUBY_VERSION)
+  end
 end