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Zookeeper >> mail # dev >> Better testing for client code...

Patrick Hunt 2011-10-31, 20:20
Mahadev Konar 2011-11-01, 04:51
Fournier, Camille F. 2011-11-01, 16:01
Patrick Hunt 2011-11-01, 16:11
Ted Dunning 2011-11-01, 18:10
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Re: Better testing for client code...
i second the need for such a mocked ZooKeeper client! there are a
couple of failure cases to test in an application that uses ZooKeeper,
but we don't provide a good library to generate them.


On Tue, Nov 1, 2011 at 11:10 AM, Ted Dunning <[EMAIL PROTECTED]> wrote:
> The testing pain that I have had most is actually the pain of testing a
> client library against failure modes.  The scaffolding that would most help
> there would be a mocked Zookeeper client that I could use to trigger
> disconnections and expirations and such.  Launching a local server is
> distinctly sub-optimal for several reasons.  One is that I can't reliably
> run tests at the same time.  Another is that it is hard to trigger possible
> race conditions with an independent server.
> It isn't terribly hard to build this, but it has so far exceeded the
> quantum of time that I typically have available.
> On Tue, Nov 1, 2011 at 9:11 AM, Patrick Hunt <[EMAIL PROTECTED]> wrote:
>> I'm not suggesting it's an all or nothing proposition.  We have a lot
>> of system/functional level testing, which is great. What we lack is
>> unit testing. Take this recent ZOOKEEPER-1271 issue as an example - in
>> many cases it's very hard, at the system level, to exercise all the
>> code paths esp the failure cases. Perhaps if we had more breadth we
>> could have caught this earlier.
>> I'm open to all types of testing, these were just some ideas I had for
>> "big bang for the buck" type scenario. I encourage you all to add
>> additional testing, or new types of testing as you see fit.
>> For example, another area where we are weak is enabling ppl to test
>> their client code, Camille if you contribute that back I think it
>> would be awesome! We could layer other things on top of that, for
>> example some way to trigger different behaviors on the servers which
>> would cause client failover and such. (the problem there is validating
>> correct client behavior).
>> Patrick
>> On Tue, Nov 1, 2011 at 9:01 AM, Fournier, Camille F.
>> <[EMAIL PROTECTED]> wrote:
>> > I also like mockito. It has some limitations but generally can be very
>> useful. However, I'm also very much a fan of fixing our code base to be
>> more testable against real servers. I actually  like the fact that we use a
>> lot of "integration" testing in our automated build. You do catch things
>> that you would miss in mockito unless you were very good at thinking
>> through all possible orderings of behavior.
>> >
>> > My internal ZK java client testing goes almost entirely against mockito
>> and in retrospect I think I would've been possibly better off using mostly
>> a real server started by the unit tests. Not that I missed a lot of bugs
>> using mockito, but what I gained in speed of tests I lost in readability of
>> the test cases for people that aren't fluent in mocking.
>> >
>> > Aspects are still a deep mystery to me. I know they can be terribly
>> useful but wow are they hard to read.
>> >
>> > I can probably throw together a few quick mockito sample tests to get
>> the ball rolling on this. After I look at some of the patch backlog.
>> >
>> > C
>> >
>> > -----Original Message-----
>> > From: Mahadev Konar [mailto:[EMAIL PROTECTED]]
>> > Sent: Tuesday, November 01, 2011 12:52 AM
>> > Subject: Re: Better testing for client code...
>> >
>> > I am all for using mockito. I have found it very handy in writing good
>> > unit tests. Our codebase needs little changes to be able to unit test
>> > our codebase.
>> >
>> > Writing a "real" unit test for the java client would be a good use
>> > case to see what all changes need to happen on the client.
>> >
>> > thanks
>> > mahadev
>> >
>> > On Mon, Oct 31, 2011 at 1:20 PM, Patrick Hunt <[EMAIL PROTECTED]> wrote:
>> >> I've been thinking that we need better testing for the client code. In
>> >> particular it's currently difficult to simulate all the different
>> >> types of failures a client might see. I'm wondering how we might do