Super interesting, I am surprised this doesn't come up more often really. I suppose the moral of the story is to avoid executing code in your modules outside of the scope of things you are exporting.
On Mon, Dec 16, 2013 at 3:46 AM, Patrick Mueller <pmue...@gmail.com> wrote: > The big problem with exporting functions - or exporting anything by using > `module.exports =` style of exporting - is recursive require problem. I > couldn't quickly find any ref to this on the web, so did a little gist: > https://gist.github.com/pmuellr/7975152 > > > On Thu, Dec 12, 2013 at 7:37 PM, Brian LeRoux <b...@brian.io> wrote: > > > Oh interesting. I can see what you mean though I think the only thing I > > should know about the output is the return value. (In your case, just a > > test for 'done'.) The behavior of the module is super important of > course. > > In the small modules philosophy the foo, bar.method, and baz would have > > thier own tests for interface/output to satisfy the case you describe. > > > > Again, IT DEPENDS! The rimraf example is a perfect case for what you > > describe. > > > > > > On Fri, Dec 13, 2013 at 10:59 AM, Gord Tanner <gtan...@gmail.com> wrote: > > > > > It depends what you define as outputs. > > > > > > in a given module: > > > > > > var foo = require('foo'), bar = require('bar'), baz = require('baz'); > > > > > > module.exports = function(a, b) { > > > foo(3); > > > bar.method(a); > > > baz(b); > > > > > > return "done"; > > > } > > > > > > I have always counted the calls to foo, bar and baz as output that > needs > > to > > > be tested. This would produce a spec like: > > > > > > "when calling this module": > > > "it calls foo with 3" > > > "it calls bar.method with a" > > > "it calls baz with b" > > > "it returns done" > > > > > > It is just easier to mock bar.method then foo > > > > > > ie: > > > > > > var rewire = require('rewire'); > > > var example = rewire('example'); //NOTE: rewire rather then require > > > example.__set__('foo', jasmine.createSpy()); > > > > > > vrs: > > > > > > var example = require('example'); > > > var bar = require('bar'); > > > spyOn(bar, "method"); > > > > > > I came across this problem when using one of Isaac's modules (rimraf > [1]) > > > where I obviously didn't want to call that in a unit test from my > module > > > but I need to mock it out. Rewire was the only way I could. > > > > > > [1] - https://github.com/isaacs/rimraf > > > > > > > > > > > > On Thu, Dec 12, 2013 at 6:37 PM, Brian LeRoux <b...@brian.io> wrote: > > > > > > > ALSO: lets avoid using terms like 'I agree' or 'I disagree'. Its > > > > programming. The answer is ALWAYS 'it depends'. No absolutes in the > sea > > > of > > > > change. > > > > > > > > > > > > On Fri, Dec 13, 2013 at 10:34 AM, Brian LeRoux <b...@brian.io> wrote: > > > > > > > > > Maybe. Have a look at Substack's code and you'll see he has no > > trouble > > > > > testing. The reason being he tests interfaces and outputs instead > of > > > > > implementations. That will be another Node 101! > > > > > > > > > > > > > > > On Fri, Dec 13, 2013 at 10:24 AM, Gord Tanner <gtan...@gmail.com> > > > wrote: > > > > > > > > > >> I also agree with this except for returning a function from > > > > >> module.exports. > > > > >> > > > > >> It is possible but makes mocking much much harder for testing. > > > > >> > > > > >> think of: > > > > >> > > > > >> > > > > >> var foo = require('foo'); > > > > >> > > > > >> module.exports = { > > > > >> awesome: function (a) { > > > > >> foo(a+1); > > > > >> } > > > > >> }; > > > > >> > > > > >> It is kind of awkward to test this module's use of the foo module. > > It > > > > can > > > > >> be done with rewire [1] but is a little awkward. > > > > >> > > > > >> If foo was designed where it exported an object literal with > > functions > > > > it > > > > >> would be much easier to mock: > > > > >> > > > > >> var foo = require('foo'); > > > > >> > > > > >> module.exports = { > > > > >> awesome: function (a) { > > > > >> foo.bar(a+1); > > > > >> } > > > > >> }; > > > > >> > > > > >> it("calls foo.bar", function () { > > > > >> var foo = require('foo'); > > > > >> spyOn(foo, "bar"); > > > > >> }); > > > > >> > > > > >> Just my 2 cents from a testing perspective. > > > > >> > > > > >> > > > > >> [1] - https://github.com/jhnns/rewire > > > > >> > > > > >> > > > > >> On Thu, Dec 12, 2013 at 6:06 PM, Brian LeRoux <b...@brian.io> wrote: > > > > >> > > > > >> > Create modules that are the smallest possible unit of code. Less > > > code > > > > is > > > > >> > fast code. Faster to write. Faster to maintain. Faster to test. > On > > > the > > > > >> > extreme end characters in the Node community such as Substack > > > > advocate a > > > > >> > single function per module definition. > > > > >> > > > > > >> > module.exports = function() { > > > > >> > // my logic here > > > > >> > } > > > > >> > > > > > >> > This is kind of extreme and not always possible but a good > > practice > > > > >> > nonetheless. The idea is not new. Its a part of the UNIX > > philosophy: > > > > "do > > > > >> > one thing well" coined by Doug Mcilroy. [1] > > > > >> > > > > > >> > It can help you make code that looks like this [2] into this > [3]. > > > > >> > > > > > >> > > > > > >> > > > > > >> > [1] > > > > http://homepage.cs.uri.edu/~thenry/resources/unix_art/ch01s06.html > > > > >> > [2] > > > > >> > > > > > >> > > > > > >> > > > > > > > > > > https://github.com/apache/cordova-js/blob/c320378b484a172a02d3ee26634bcc584f43b939/Gruntfile.js > > > > >> > [3] > https://github.com/apache/cordova-js/blob/master/Gruntfile.js > > > > >> > > > > > >> > > > > > > > > > > > > > > > > > > > > > > > -- > Patrick Mueller > http://muellerware.org >
