/
about_objects.rb
60 lines (51 loc) · 1.76 KB
/
about_objects.rb
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require File.expand_path(File.dirname(__FILE__) + '/neo')
class AboutObjects < Neo::Koan
def test_everything_is_an_object
assert_equal true, 1.is_a?(Object)
assert_equal true, 1.5.is_a?(Object)
assert_equal true, "string".is_a?(Object)
assert_equal true, nil.is_a?(Object)
assert_equal true, Object.is_a?(Object)
end
# to_s returns a string representation of an object
def test_objects_can_be_converted_to_strings
assert_equal "123", 123.to_s
assert_equal '', nil.to_s
end
# inspect returns a string containing a human-readable representation
# of an object that's more often used for debugging purposes
def test_objects_can_be_inspected
assert_equal "123", 123.inspect
assert_equal 'nil', nil.inspect
end
def test_every_object_has_an_id
obj = Object.new
assert_equal Fixnum, obj.object_id.class
end
# Every object responds to an object_id method that returns a unique id for
# each object. You can compare object ids to see whether two objects are
# the same or different instances
def test_every_object_has_different_id
obj = Object.new
another_obj = Object.new
assert_equal true, obj.object_id != another_obj.object_id
end
# Yep, small integers have fixed object IDs.
def test_small_integers_have_fixed_ids
assert_equal 1, 0.object_id
assert_equal 3, 1.object_id
assert_equal 5, 2.object_id
assert_equal 201, 100.object_id
# THINK ABOUT IT:
# What pattern do the object IDs for small integers follow?
#
# num.object_id = 2*num + 1
end
# Clone creates a new instance
def test_clone_creates_a_different_object
obj = Object.new
copy = obj.clone
assert_equal true, obj != copy
assert_equal true, obj.object_id != copy.object_id
end
end