test_last_day_of_2019_year.rb

require 'date'
require 'test/unit'
require 'test/unit/ui/console/testrunner'

class TestDate < Test::Unit::TestCase
  def test_that_today_is_last_day_of_the_year
    assert_equal Date.today, Date.civil(2019, 12, 31)
  end
end

saiury_tests = TestDate.new('test_that_today_is_last_day_of_the_year')
Test::Unit::UI::Console::TestRunner.run(saiury_tests)

#=> 1 tests, 1 assertions, 0 failures, 0 errors, 0 pendings, 0 omissions, 0 notifications
#   100% passed