You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
39 lines
1.0 KiB
39 lines
1.0 KiB
14 years ago
|
require File.expand_path(File.dirname(__FILE__) + '/edgecase')
|
||
|
|
|
||
|
|
class AboutNil < EdgeCase::Koan
|
||
|
|
def test_nil_is_an_object
|
||
|
|
assert_equal __, 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
|
||
|
|
# make some assertions about it.
|
||
|
|
begin
|
||
|
|
nil.some_method_nil_doesnt_know_about
|
||
|
|
rescue Exception => ex
|
||
|
|
# What exception has been caught?
|
||
|
|
assert_equal __, ex.class
|
||
|
|
|
||
|
|
# What message was attached to the exception?
|
||
|
|
# (HINT: replace __ with part of the error message.)
|
||
|
|
assert_match(/__/, ex.message)
|
||
|
|
end
|
||
|
|
end
|
||
|
|
|
||
|
|
def test_nil_has_a_few_methods_defined_on_it
|
||
|
|
assert_equal __, nil.nil?
|
||
|
|
assert_equal __, nil.to_s
|
||
|
|
assert_equal __, nil.inspect
|
||
|
|
|
||
|
|
# THINK ABOUT IT:
|
||
|
|
#
|
||
|
|
# Is it better to use
|
||
|
|
# obj.nil?
|
||
|
|
# or
|
||
|
|
# obj == nil
|
||
|
|
# Why?
|
||
|
|
end
|
||
|
|
|
||
|
|
end
|