的使用,我对Exercise 49 of Learn Ruby the Hard Way正确Assert_Raise单元测试和异常类
工作的练习要求写出所提供的每项功能的单元测试。我正在测试的项目之一是如果提出适当的例外。建议我们使用assert_raise
来达到这个目的。
这里是我的测试代码:
class ParserError < Exception
end
Pair = Struct.new(:token, :word)
def peek(word_list)
begin
word_list.first.token
rescue
nil
end
end
def match(word_list, expecting)
word = word_list.shift
if word.token == expecting
word
else
nil
end
end
def skip_word(word_list, token)
while peek(word_list) == token
match(word_list, token)
end
end
def parse_verb(word_list)
skip_word(word_list, :stop)
if peek(word_list) == :verb
return match(word_list, :verb)
else
raise ParserError.new("Expected a verb next.")
end
end
这里是考验,对于功能parse_verb:
def test_parse_verb
list_one = [Pair.new(:verb, 'go'), Pair.new(:noun, 'king')]
assert_equal(parse_verb(list_one), Pair.new(:verb, 'go'))
list_two = [Pair.new(:noun, 'player') ,Pair.new(:verb, 'go'), Pair.new(:noun, 'king')]
assert_raise(ParserError.new("Expected a verb next.")) {parse_verb(list_two)}
end
当我运行测试,它失败,这里是消息我得到:
Larson-2:test larson$ ruby test_sentence.rb
Loaded suite test_sentence
Started
.F..
Finished in 0.001204 seconds.
1) Failure:
test_parse_verb(SentenceTests) [test_sentence.rb:36]:
[#<ParserError: Expected a noun or direction next.>] exception expected, not
Class: <ParserError>
Message: <"Expected a verb next.">
---Backtrace---
/Users/larson/Ruby/projects/ex48/lib/sentence.rb:45:in `parse_verb'
test_sentence.rb:36:in `block in test_parse_verb'
---------------
4 tests, 7 assertions, 1 failures, 0 errors, 0 skips
Test run options: --seed 40627
根据我对assert_raise
函数的理解,这个测试应该通过,我使用它的方式有什么问题吗?
如果有人想所有文件的完整的源代码,我有我的工作是提供here
感谢您的帮助!这解决了我的问题。 –