我有一个文件app.coffee：
class TaskList
class Task
constructor: (@name) ->
@status = 'incomplete'
complete: ->
if @parent? and @parent.status isnt 'completed'
throw "Dependent task '#{@parent.name}' is not completed."
@status = 'complete'
true
dependsOn: (@parent) ->
@parent.child = @
@status = 'dependent'
# Prepare scope stuff
root = exports ? window
root.TaskList = TaskList
root.Task = Task
和一个名为test / taskTest.coffee的文件：
{TaskList,Task} = require '../app'
should = require 'should'
describe 'Task Instance',->
task1 = task2 = null
it 'should have a name',->
something = 'asdf'
something.should.equal 'asdf'
task1 = new Task 'Feed the cat'
task1.name.should.equal 'Feed the cat'
it 'should be initially incomplete',->
task1.status.should.equal 'incomplete'
it 'should be able to be completed',->
task1.complete().should.be.true
task1.status.should.equal 'complete'
it 'should be able to be dependent on another task',->
task1 = new Task 'wash dishes'
task2 = new Task 'dry dishes'
task2.dependsOn task1
task2.status.should.equal 'dependent'
task2.parent.should.equal task1
task1.child.should.equal task2
it 'should refuse completion it is dependent on an uncompleted task',->
(-> task2.complete()).should.throw "Dependent task 'wash dishes' is not completed."
如果我在终端中运行此命令：mocha -r should –compilers coffee：coffee-script -R spec我有一个失败的测试(最后一个)说它期待一个异常“依赖任务’洗碗’没有完成“.但得到了“未定义”.
如果我改变( – > task2.complete()).should.throw to – > task2.complete().should.throw删除括号,测试通过,如果我不抛出异常则失败.但是,如果我将异常消息更改为随机的消息,它仍然会通过.难道我做错了什么？如果消息字面意思是“依赖任务’洗碗’没有完成,那么测试不应该通过.”？
解决方法
您正在使用字符串抛出异常而不是抛出错误对象. throw()寻找后者.因此,如果您执行以下操作,原始代
throw new Error "Dependent task '#{@parent.name}' is not completed."
如果您在CoffeeScript中编写的内容产生的结果毫无意义,请尝试将其编译为js(或将代码粘贴到try CoffeeScript中.您将看到：
-> task2.complete().should.throw "Dependent task 'wash dishes' is not completed."
编译为：
(function() {
return task2.complete().should["throw"]("Dependent task 'wash dishes' is not completed.");
});