Validation.rb

begin
  require 'bundler/inline'
rescue LoadError => e
  $stderr.puts 'Bundler version 1.10 or later is required. Please update your Bundler'
  raise e
end

gemfile(true) do
  source 'https://rubygems.org'
  gem 'rails', github: 'rails/rails'
  gem 'sqlite3'
end

require 'active_record'
require 'minitest/autorun'
require 'logger'

ActiveRecord::Base.establish_connection(adapter: 'sqlite3', database: ':memory:')
ActiveRecord::Base.logger = Logger.new(STDOUT)

ActiveRecord::Schema.define do
  create_table :comments, force: true do |t|
    t.integer :some_value
  end
end

class Comment < ActiveRecord::Base
  validates :some_value, presence: true, numericality: { integer: true, greater_than: 1, if: :times_used? }

  def times_used?
    true
  end
end

class BugTest < Minitest::Test
  def test_validation_numericality
    comment = Comment.new
    comment.some_value = 0.5

    refute comment.valid?
    assert_equal 'Some value must be greater than 1', comment.errors.full_messages_for(:some_value).first
  end
end