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require File.expand_path(File.dirname(__FILE__) + '/edgecase')
class AboutNil < EdgeCase::Koan
def test_nil_is_an_object
assert_equal true, nil.is_a?(Object), "Unlike NULL in other languages"
end
def test_you_dont_get_null_pointer_errors_when_calling_methods_on_nil
# What happens when you call a method that doesn't exist. The
# following begin/rescue/end code block captures the exception and
# makes some assertions about it.
begin
nil.some_method_nil_doesnt_know_about
rescue Exception => ex
# What exception has been caught?
puts ex.class
assert_equal NoMethodError,ex.class
# What message was attached to the exception?
# (HINT: replace __ with part of the error message.)
assert_match(/doesnt/, ex.message)
end
end
def test_nil_has_a_few_methods_defined_on_it
assert_equal true, nil.nil?
assert_equal '', nil.to_s
assert_equal 'nil', nil.inspect
# THINK ABOUT IT:
#
# Is it better to use
# obj.nil?
# or
# obj == nil
# Why?
end
end