My argument is that I am actually categorically against having a requirement that the same input values be used for testing for every run.
I don't personally view "convenience in reproducing" as outweighing "finding edge cases that I didn't think of or that haven't been tried before". On Mon, Oct 16, 2017 at 9:34 AM, Pedro Larroy <pedro.larroy.li...@gmail.com> wrote: > It's always going to be deterministic one way or another unless you use > random from the entropy pool such as /dev/random. I don't think it's a good > practice not to seed properly and have values depend on execution order / > parallelism / time or whatever, but that's just my opinion. I would want to > use the same values for all test runs for reproducibility. > > I think your argument goes more towards the previously mentioned "property > based testing" approach, which is in the spirit of what you are supporting, > if I'm not mistaken. > > On Mon, Oct 16, 2017 at 6:22 PM, Chris Olivier <cjolivie...@gmail.com> > wrote: > > > My take on the suggestion of purely deterministic inputs is (including > > deterministic seeding): > > > > "I want the same values to be used for all test runs because it is > > inconvenient when a unit test fails for some edge cases. I prefer that > > unforseen edge case failures occur in the field and not during testing". > > > > Is this the motivation? Seems strange to me. > > > > > > On Mon, Oct 16, 2017 at 9:09 AM, Pedro Larroy < > > pedro.larroy.li...@gmail.com> > > wrote: > > > > > I think using a properly seeded and initialized (pseudo)random is > > actually > > > beneficial (and deterministic), handpicked examples are usually too > > > simplistic and miss corner cases. > > > > > > Better yet is to use property based testing, which will pick corner > cases > > > and do fuzzing automatically to check with high degree of confidence > > that a > > > testing condition holds. > > > > > > Probably it would be good if we use a property based testing library in > > > adition to nose to check invariants. > > > > > > A quick googling yields this one for python for example: > > > https://hypothesis.readthedocs.io/en/latest/quickstart.html does > anyone > > > have experience or can recommend a nice property based testing library > > for > > > python? > > > > > > > > > Regards > > > > > > On Mon, Oct 16, 2017 at 4:56 PM, Bhavin Thaker <bhavintha...@gmail.com > > > > > wrote: > > > > > > > I agree with Pedro. > > > > > > > > Based on various observations on unit test failures, I would like to > > > > propose a few guidelines to follow for the unit tests. Even though I > > use > > > > the word, “must” for my humble opinions below, please feel free to > > > suggest > > > > alternatives or modifications to these guidelines: > > > > > > > > 1) 1a) Each unit test must have a run time budget <= X minutes. Say, > X > > = > > > 2 > > > > minutes max. > > > > 1b) The total run time budget for all unit tests <= Y minutes. Say, > Y = > > > 60 > > > > minutes max. > > > > > > > > 2) All Unit tests must have deterministic (not Stochastic) behavior. > > That > > > > is, instead of using the random() function to test a range of input > > > values, > > > > each input test value must be carefully hand-picked to represent the > > > > commonly used input scenarios. The correct place to stochastically > test > > > > random input values is to have continuously running nightly tests and > > NOT > > > > the sanity/smoke/unit tests for each PR. > > > > > > > > 3) All Unit tests must be as much self-contained and independent of > > > > external components as possible. For example, datasets required for > the > > > > unit test must NOT be present on external website which, if > > unreachable, > > > > can cause test run failures. Instead, all datasets must be available > > > > locally. > > > > > > > > 4) It is impossible to test everything in unit tests and so only > common > > > > use-cases and code-paths must be tested in unit-tests. Less common > > > > scenarios like integration with 3rd party products must be tested in > > > > nightly/weekly tests. > > > > > > > > 5) A unit test must NOT be disabled on a failure unless proven to > > exhibit > > > > unreliable behavior. The burden-of-proof for a test failure must be > on > > > the > > > > PR submitter and the PR must NOT be merged without a opening a new > > github > > > > issue explaining the problem. If the unit test is disabled for some > > > reason, > > > > then the unit test must NOT be removed from the unit tests list; > > instead > > > > the unit test must be modified to add the following lines at the > start > > of > > > > the test: > > > > Print(“Unit Test DISABLED; see GitHub issue: NNNN”) > > > > Exit(0) > > > > > > > > Please suggest modifications to the above proposal such that we can > > make > > > > the unit tests framework to be the rock-solid foundation for the > active > > > > development of Apache MXNet (Incubating). > > > > > > > > Regards, > > > > Bhavin Thaker. > > > > > > > > > > > > On Mon, Oct 16, 2017 at 5:56 AM Pedro Larroy < > > > pedro.larroy.li...@gmail.com > > > > > > > > > wrote: > > > > > > > > > Hi > > > > > > > > > > Some of the unit tests are extremely costly in terms of memory and > > > > compute. > > > > > > > > > > As an example in the gluon tests we are loading all the datasets. > > > > > > > > > > test_gluon_data.test_datasets > > > > > > > > > > Also running huge networks like resnets in test_gluon_model_zoo. > > > > > > > > > > This is ridiculously slow, and straight impossible on some > embedded / > > > > > memory constrained devices, and anyway is making tests run for > longer > > > > than > > > > > needed. > > > > > > > > > > Unit tests should be small, self contained, if possible pure > > (avoiding > > > > this > > > > > kind of dataset IO if possible). > > > > > > > > > > I think it would be better to split them in real unit tests and > > > extended > > > > > integration test suites that do more intensive computation. This > > would > > > > also > > > > > help with the feedback time with PRs and CI infrastructure. > > > > > > > > > > > > > > > Thoughts? > > > > > > > > > > > > > > >
