box-o-sand/koans/about_objects.rb

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require File.expand_path(File.dirname(__FILE__) + '/edgecase')
class AboutObjects < EdgeCase::Koan
def test_everything_is_an_object
assert_equal __, 1.is_a?(Object)
assert_equal __, 1.5.is_a?(Object)
assert_equal __, "string".is_a?(Object)
assert_equal __, nil.is_a?(Object)
assert_equal __, Object.is_a?(Object)
end
def test_objects_can_be_converted_to_strings
assert_equal __, 123.to_s
assert_equal __, nil.to_s
end
def test_objects_can_be_inspected
assert_equal __, 123.inspect
assert_equal __, nil.inspect
end
def test_every_object_has_an_id
obj = Object.new
assert_equal __, obj.object_id.class
end
def test_every_object_has_different_id
obj = Object.new
another_obj = Object.new
assert_equal __, obj.object_id != another_obj.object_id
end
def test_some_system_objects_always_have_the_same_id
assert_equal __, false.object_id
assert_equal __, true.object_id
assert_equal __, nil.object_id
end
def test_small_integers_have_fixed_ids
assert_equal __, 0.object_id
assert_equal __, 1.object_id
assert_equal __, 2.object_id
assert_equal __, 100.object_id
# THINK ABOUT IT:
# What pattern do the object IDs for small integers follow?
end
def test_clone_creates_a_different_object
obj = Object.new
copy = obj.clone
assert_equal __, obj != copy
assert_equal __, obj.object_id != copy.object_id
end
end