[rspec] before :each还是let？
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yuan
2011-06-15
http://stackoverflow.com/questions/5359558/when-to-use-rspec-let
Myron 写道 I always prefer let to an instance variable for a couple of reasons:
Instance variables spring into existence when referenced. This means that if you fat finger the spelling of the instance variable, a new one will be created and initialized to nil, which can lead to subtle bugs and false positives. Since let creates a a method, you'll get a NameError when you misspell it, which I find preferable. It makes it easier to refactor specs, too. A before(:each) hook will run before each example, even if the example doesn't use any of the instance variables defined in the hook. This isn't usually a big deal, but if the setup of the instance variable takes a long time, then you're wasting cycles. For the method defined by let, the initialization code only runs if the example calls it. This is a bit subjective, but as Mike Lewis pointed out, I think it makes the spec easier to read. I like the organization of defining all my dependent objects with let and keeping my it block nice and short. |
