From a2a4176bcd74dc6c607d48131f26cb5fa4affb3d Mon Sep 17 00:00:00 2001 From: Thomas Schwinge Date: Sat, 26 Mar 2011 01:42:25 +0100 Subject: open_issues/unit_testing: Move discussion to community/gsoc/project_ideas/testing_framework/discussion. --- .../testing_framework/discussion.mdwn | 270 +++++++++++++++++++++ 1 file changed, 270 insertions(+) create mode 100644 community/gsoc/project_ideas/testing_framework/discussion.mdwn (limited to 'community/gsoc/project_ideas/testing_framework/discussion.mdwn') diff --git a/community/gsoc/project_ideas/testing_framework/discussion.mdwn b/community/gsoc/project_ideas/testing_framework/discussion.mdwn new file mode 100644 index 00000000..872d0eb7 --- /dev/null +++ b/community/gsoc/project_ideas/testing_framework/discussion.mdwn @@ -0,0 +1,270 @@ +[[!meta copyright="Copyright © 2010, 2011 Free Software Foundation, Inc."]] + +[[!meta license="""[[!toggle id="license" text="GFDL 1.2+"]][[!toggleable +id="license" text="Permission is granted to copy, distribute and/or modify this +document under the terms of the GNU Free Documentation License, Version 1.2 or +any later version published by the Free Software Foundation; with no Invariant +Sections, no Front-Cover Texts, and no Back-Cover Texts. A copy of the license +is included in the section entitled [[GNU Free Documentation +License|/fdl]]."]]"""]] + +freenode, #hurd channel, 2011-03-05: + + what about testing though? + like sort of "what's missing? lets write tests for it so that + when someone gets to implementing it, he knows what to do. Repeat" + project + you mean creating an automated testing framework? + this is actually a task I want to add for this year, if I get + around to it :-) + yeah I'd very much want to apply for that one + cuz I've never done Kernel hacking before, but I know that with + the right tasks like "test VM functionality", I would be able to write up + the automated tests and hopefully learn more about what breaks/makes the + kernel + (and it would make implementing the feature much less hand-wavy + and more correct) + antrik, I believe the framework(CUnit right?) exists, but we just + need to write the tests. + do you have prior experience implementing automated tests? + lots of tests! + yes, in Java mostly, but I've played around with CUnit + ah, great :-) + here's what I know from experience: 1) write basic tests. 2) + write ones that test multiple features 3) stress test [option 4) + benchmark and record to DB] + well, what we'd rather need is to fix the issues we already know + from the existing testsuites :) + +[[GSoC project propsal|community/gsoc/project_ideas/testsuites]]. + + youpi, true, and I think I should check what's available in way + of tests, but if the tests are "all or nothing" then it becomes really + hard to fix your mistakes + they're not all or nothing + youpi: the existing testsuites don't test specific system features + libc ones do + we could also check posixtestsuite which does too + +[[open_issues/open_posix_test_suite]]. + + AFAIK libc has very few failing tests + +[[open_issues/glibc_testsuite]]. + + err, like twenty? + € grep -v '^#' expected-results-i486-gnu-libc | wc -l + 67 + nope, even more + oh, sorry, I confused it with coreutils + plus the binutils ones, i guess + yes + +[[open_issues/binutils#weak]]. + + anyways, I don't think relying on external testsuites for + regression testing is a good plan + also, that doesn't cover unit testing at all + why ? + sure there can be unit testing at the translator etc. level + if we want to implement test-driven development, and/or do serious + refactoring without too much risk, we need a test harness where we can + add specific tests as needed + but more than often, the issues are at the libc / etc. level + because of a combination o fthings at the translator level, which unit + testing won't find out + * nixness yewzzz! + sure unit testing can find them out. if they're good "unit" tests + the problem is that you don't necessarily know what "good" means + e.g. for posix correctness + since it's not posix + but if they're composite clever tests, then you lose that + granularity + youpi, is that a blackbox test intended to be run at the very end + to check if you're posix compliant? + also, if we have our own test harness, we can run tests + automatically as part of the build process, which is a great plus IMHO + nixness: "that" = ? + oh nvm, I thought there was a test stuie called "posix + correctness" + there's the posixtestsuite yes + it's an external one however + antrik: being external doesn't mean we can't invoke it + automatically as part of the build process when it's available + youpi, but being internal means it can test the inner workings of + certain modules that you are unsure of, and not just the interface + sure, that's why I said it'd be useful too + but as I said too, most bugs I've seen were not easy to find out at + the unit level + but rather at the libc level + of course we can integrate external tests if they exist and are + suitable. but that that doesn't preclude adding our own ones too. in + either case, that integration work has to be done too + again, I've never said I was against internal testsuite + also, the major purpose of a test suite is checking known + behaviour. a low-level test won't directly point to a POSIX violation; + but it will catch any changes in behaviour that would lead to one + what I said is that it will be hard to write them tight enough to + find bugs + again, the problem is knowing what will lead to a POSIX violation + it's long work + while libc / posixtestsuite / etc. already do that + *any* unexpected change in behaviour is likely to cause bugs + somewher + but WHAT is "expected" ? + THAT is the issue + and libc/posixtessuite do know that + at the translator level we don't really + see the recent post about link() + +[link(dir,name) should fail with +EPERM](http://lists.gnu.org/archive/html/bug-hurd/2011-03/msg00007.html) + + in my memory jkoenig pointed it out for a lot of such calls + and that issue is clearly not known at the translator level + so you're saying that the tests have to be really really + low-level, and work our way up? + I'm saying that the translator level tests will be difficult to + write + why isn't it known at the translator level? if it's a translator + (not libc) bug, than obviously the translator must return something wrong + at some point, and that's something we can check + because you'll have to know all the details of the combinations + used in libc, to know whether they'll lead to posix issues + antrik: sure, but how did we detect that that was unexpected + behavior? + because of a glib test + at the translator level we didn't know it was an unexpected + behavior + gnulib actually + and if you had asked me, I wouldn't have known + again, we do *not* write a test suite to find existing bugs + right, took one for the other + doesn't really matter actually + antrik: ok, I don't care then + we write a test suite to prevent future bugs, or track status of + known bugs + (don't care *enough* for now, I mean) + hmm, so write something up antrik for GSoC :) and I'll be sure to + apply + now that we know some translators return a wrong error status in a + particular situation, we can write a test that checks exactly this error + status. that way we know when it is fixed, and also when it breaks again + nixness: great :-) + sweet. that kind of thing would also need a db backend + nixness: BTW, if you have a good idea, you can send an application + for it even if it's not listed among the proposed tasks... + so you don't strictly need a writeup from me to apply for this :-) + antrik, I'll keep that in mind, but I'll also be checking your + draft page + oh cool :) + (and it's a well known fact that those projects which students + proposed themselfs tend to be the most successful ones :-) ) + * nixness draft initiated + youpi: BTW, I'm surprised that you didn't mention libc testsuite + before... working up from there is probably a more effective plan than + starting with high-level test suites like Python etc... + wasn't it already in the gsoc proposal? + bummer + nope + +freenode, #hurd channel, 2011-03-06: + + how's the hurd coding workflow, typically? + +*nixness* -> *foocraft*. + + we're discussing how TDD can work with Hurd (or general kernel + development) on #osdev + so what I wanted to know, since I haven't dealt much with GNU + Hurd, is how do you guys go about coding, in this case + Our current workflow scheme is... well... is... + Someone wants to work on something, or spots a bug, then works + on it, submits a patch, and 0 to 10 years later it is applied. + Roughly. + hmm so there's no indicator of whether things broke with that + patch + and how low do you think we can get with tests? A friend of mine + was telling me that with kernel dev, you really don't know whether, for + instance, the stack even exists, and a lot of things that I, as a + programmer, can assume while writing code break when it comes to writing + kernel code + Autotest seems promising + +See autotest link given above. + + but in any case, coming up with the testing framework that + doesn't break when the OS itself breaks is hard, it seems + not sure if autotest isolates the mistakes in the os from + finding their way in the validity of the tests themselves + it could be interesting to have scripts that automatically start a + sub-hurd to do the tests + +[[hurd/subhurd#unit_testing]]. + + foocraft: To answer one of your earlier questions: you can do + really low-level testing. Like testing Mach's message passing. A + million times. The questions is whether that makes sense. And / or if + it makes sense to do that as part of a unit testing framework. Or rather + do such things manually once you suspect an error somewhere. + The reason for the latter may be that Mach IPC is already + heavily tested during normal system operation. + And yet, there still may be (there are, surely) bugs. + But I guess that you have to stop at some (arbitrary?) level. + so we'd assume it works, and test from there + Otherwise you'd be implementing the exact counter-part of what + you're testing. + Which may be what you want, or may be not. Or it may just not + be feasible. + maybe the testing framework should have dependencies + which we can automate using make, and phony targets that run + tests + so everyone writes a test suite and says that it depends on A + and B working correctly + then it'd go try to run the tests for A etc. + Hmm, isn't that -- on a high level -- have you have by + different packages? For example, the perl testsuite depends (inherently) + on glibc working properly. A perl program's testsuite depends on perl + working properly. + yeah, but afaik, the ordering is done by hand + +freenode, #hurd channel, 2011-03-07: + + actually, I think for most tests it would be better not to use a + subhurd... that leads precisely to the problem that if something is + broken, you might have a hard time running the tests at all :-) + foocraft: most of the Hurd code isn't really low-level. you can + use normal debugging and testing methods + gnumach of course *does* have some low-level stuff, so if you add + unit tests to gnumach too, you might run into issues :-) + tschwinge: I think testing IPC is a good thing. as I already said, + automated testing is *not* to discover existing but unknown bugs, but to + prevent new ones creeping in, and tracking progress on known bugs + tschwinge: I think you are confusing unit testing and regression + testing. http://www.bddebian.com/~hurd-web/open_issues/unit_testing/ + talks about unit testing, but a lot (most?) of it is actually about + regression tests... + antrik: That may certainly be -- I'm not at all an expert in + this, and just generally though that some sort of automated testing is + needed, and thus started collecting ideas. + antrik: You're of course invited to fix that. + +IRC, freenode, #hurd, 2011-03-08 + +(After discussing the [[open_issues/anatomy_of_a_hurd_system]].) + + so that's what your question is actually about? + so what I would imagine is a set of only-this-server tests for + each server, and then we can have fun adding composite tests + thus making debugging the composite scenarios a bit less tricky + indeed + and if you were trying to pass a composite test, it would also + help knowing that you still didn't break the server-only test + there are so many different things that can be tested... the + summer will only suffice to dip into this really :-) + yeah, I'm designing my proposal to focus on 1) make/use a + testing framework that fits the Hurd case very well 2) write some tests + and docs on how to write good tests + well, doesn't have to be *one* framework... unit testing and + regression testing are quite different things, which can be covered by + different frameworks -- cgit v1.2.3