require 'test/unit' TEST_TOPLEVEL_CONST = true class TestDefined < Test::Unit::TestCase class Sample class << self def set_the_var(value) @@some_var = value end def the_var_inited? defined? @@some_var end end end def test_defined_class_var assert !Sample.the_var_inited? Sample.set_the_var('something') assert Sample.the_var_inited? end def test_toplevel_const_defined assert_equal "constant", defined?(::TEST_TOPLEVEL_CONST) end def test_inner_const_defined assert_equal "constant", defined?(TestDefined::Sample) end end