For the randomness argument, I am more concerned of a unit test that exhibits different behaviors for different runs. Stochastic test, IMHO, is not a good sanity test, because the code entry Quality bar is stochastic rather than deterministic — causing a lot of churn for diagnosing Unit test failures for PRs.
There are other places (nightly) to do extensive tests. PR-unit-tests are sanity tests and must be quick, reliable and consistent for every PR. Bhavin Thaker. On Mon, Oct 16, 2017 at 8:51 AM Pedro Larroy <[email protected]> wrote: > That's not true. random() and similar functions are based on a PRNG. It > can be debugged and it's completely deterministic, a good practice is to > use a known seed for this. > > More info: https://en.wikipedia.org/wiki/Pseudorandom_number_generator > > On Mon, Oct 16, 2017 at 5:42 PM, pracheer gupta < > [email protected]> wrote: > >> @Chris: Any particular reason for -1? Randomness just prevents in writing >> tests that you can rely on and/or debug later on in case of failure. >> >> On Oct 16, 2017, at 8:28 AM, Chris Olivier <[email protected]<mailto: >> [email protected]>> wrote: >> >> -1 for "must not use random numbers for input" >> >> On Mon, Oct 16, 2017 at 7:56 AM, Bhavin Thaker <[email protected] >> <mailto:[email protected]>> > > >> 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 < >> [email protected]<mailto:[email protected]> > > >> >> 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? >> >> >>
