From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-11.4 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_IN_DEF_DKIM_WL autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 57FBDC433DF for ; Thu, 27 Aug 2020 18:28:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2E5462087E for ; Thu, 27 Aug 2020 18:28:20 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="peXan55M" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726120AbgH0S2T (ORCPT ); Thu, 27 Aug 2020 14:28:19 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39108 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726291AbgH0S2Q (ORCPT ); Thu, 27 Aug 2020 14:28:16 -0400 Received: from mail-oo1-xc43.google.com (mail-oo1-xc43.google.com [IPv6:2607:f8b0:4864:20::c43]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 00890C06121B for ; Thu, 27 Aug 2020 11:28:15 -0700 (PDT) Received: by mail-oo1-xc43.google.com with SMTP id y30so1452776ooj.3 for ; Thu, 27 Aug 2020 11:28:15 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=VxlbWvka+07kHZPf01+EUiW1alBItC8Pr3Tn8LbFklQ=; b=peXan55M41airQcwalxfGsmf4nrB+F5Ll5GMwX64kU3Vo+5HB9b0f6CVxw1o5JIs3q qZ1b9XUIpYjcqMCSHU5FYiwzFopbgLt5b5goPNP3CJiLS26g40+KVQQHRs19X8ec+wXI Xvr5EvMmOs1yZkUPeL/kQlKWiXmXba5jtBQAySYJNjc4Rm/i1YZoaPMdb2vMwvr+/FTw x0tessMx4QzIUMHJHQ+JdDglMcj79qIbKsnVSgvYulpOR68h2/iijrZIV/E9/izUpTwq CUOXq35T8mtWgQFiElp3fpAP2sfUGIMa427iA9whE8zHrop8cZewgZmKWf2O3h3R4MSx vtsw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=VxlbWvka+07kHZPf01+EUiW1alBItC8Pr3Tn8LbFklQ=; b=nPxxZLnT+Egn0mzTWSdkjD2RuZCiBWxdZ+D84/3nb+Aj3amgIiKrIFRNUo11U+4ej9 m0q4YiF8JdGoapE1e/857XQBEGB8PlMVRFKtyewOhPDaB9CHmidka0az1ZFywbH5LFVa gcUb5SLTVm+29k+b6CGpF423F4symQkKxnl3FyqpPP7Cm1543iqdFGriJttyrczHZsXM v4M2PjdLG/nOp+U4lfBA3LhlNm5xlzPSvGRssc7DQKdK7lPnKK1eqz9szLdGRk6HHH0E ORRtBehnSisDT8MS8GxjR4IQnGf5j4SPFC5RfRvjoqtzIvr0g5KqEFtyB7PshxDFFIu5 Ur+g== X-Gm-Message-State: AOAM532b8p/WlNH89hg+/EWbdltCHVfzAE2WOPxgyKKRVcZ95+QEGX92 B2f21jwqTjgEXmfjDU9vV/hwbeqb0Mzb3rXtq8gjkw== X-Google-Smtp-Source: ABdhPJyZof+lv2Rdb068ddJIG0Fuq/ptEYfL7PHggKV923EZOQ/WvcqDXzxtwSckF1WY8r2ySti4FCh5wtjONGhRl3g= X-Received: by 2002:a05:6820:24c:: with SMTP id b12mr15207106ooe.36.1598552894223; Thu, 27 Aug 2020 11:28:14 -0700 (PDT) MIME-Version: 1.0 References: <20200702071416.1780522-1-davidgow@google.com> <20200827131438.GA3597431@elver.google.com> In-Reply-To: From: Marco Elver Date: Thu, 27 Aug 2020 20:28:03 +0200 Message-ID: Subject: Re: [PATCH] Documentation: kunit: Add naming guidelines To: David Gow Cc: Brendan Higgins , Jonathan Corbet , Kees Cook , Alan Maguire , Randy Dunlap , "Theodore Ts'o" , Tim Bird , KUnit Development , "open list:KERNEL SELFTEST FRAMEWORK" , "open list:DOCUMENTATION" , Linux Kernel Mailing List Content-Type: text/plain; charset="UTF-8" Sender: linux-kselftest-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kselftest@vger.kernel.org On Thu, 27 Aug 2020 at 18:17, David Gow wrote: [...] > > First of all, thanks for the talk yesterday! I only looked at this > > because somebody pasted the LKML link. :-) > > No worries! Clearly this document needed linking -- even I was > starting to suspect the reason no-one was complaining about this was > that no-one had read it. :-) [...] > > > > While I guess this ship has sailed, and *_kunit.c is the naming > > convention now, I hope this is still just a recommendation and names of > > the form *-test.c are not banned! > > The ship hasn't technically sailed until this patch is actually > accepted. Thus far, we hadn't had any real complaints about the > _kunit.c idea, though that may have been due to this email not > reaching enough people. If you haven't read the discussion in > https://lore.kernel.org/linux-kselftest/202006141005.BA19A9D3@keescook/t/#u > it's worthwhile: the _kunit.c name is discussed, and Kees lays out > some more detailed rationale for it as well. Thanks, I can see the rationale. AFAIK the main concern was "it does not distinguish it from other tests". > > $> git grep 'KUNIT.*-test.o' > > drivers/base/power/Makefile:obj-$(CONFIG_PM_QOS_KUNIT_TEST) += qos-test.o > > drivers/base/test/Makefile:obj-$(CONFIG_KUNIT_DRIVER_PE_TEST) += property-entry-test.o > > fs/ext4/Makefile:obj-$(CONFIG_EXT4_KUNIT_TESTS) += ext4-inode-test.o > > kernel/Makefile:obj-$(CONFIG_SYSCTL_KUNIT_TEST) += sysctl-test.o > > lib/Makefile:obj-$(CONFIG_LIST_KUNIT_TEST) += list-test.o > > lib/kunit/Makefile:obj-$(CONFIG_KUNIT_TEST) += kunit-test.o > > lib/kunit/Makefile:obj-$(CONFIG_KUNIT_TEST) += string-stream-test.o > > lib/kunit/Makefile:obj-$(CONFIG_KUNIT_EXAMPLE_TEST) += kunit-example-test.o > > > > $> git grep 'KUNIT.*_kunit.o' > > # Returns nothing > > > > This was definitely something we noted. Part of the goal of having > _kunit.c as a filename suffix (and, perhaps more importantly, the > _kunit module name suffix) was to have a way of both distinguishing > KUnit tests from non-KUnit ones (of which there are quite a few > already with -test names), and to have a way of quickly determining > what modules contain KUnit tests. That really only works if everyone > is using it, so the plan was to push this as much as possible. This'd > probably include renaming most of the existing test files to match, > which is a bit of a pain (particularly when converting non-KUnit tests > to KUnit and similar), but is a one-time thing. Feel free to ignore the below, but here might be one concern: I think the problem of distinguishing KUnit tests from non-KUnit tests is a technical problem (in fact, the Kconfig entries have all the info we need), but a solution that sacrifices readability might cause unnecessary friction. The main issue I foresee is that the _kunit.c name is opaque as to what the file does, but merely indicates one of its dependencies. Most of us clearly know that KUnit is a test framework, but it's a level of indirection nevertheless. (But _kunit_test.c is also bad, because it's unnecessarily long.) For a dozen tests, that's probably still fine. But now imagine 100s of tests, people will quickly wonder "what's this _kunit thing?". And if KUnit tests are eventually the dominant tests, does it still matter? I worry that because of the difficulty of enforcing the name, choosing something unintuitive will also achieve the opposite result: proliferation of even more diverse names. A generic convention like "*-test.c" will be close enough to what's intuitive for most people, and we might actually have a chance of getting everyone to stick to it. The problem of identifying all KUnit tests can be solved with a script. > > Just an idea: Maybe the names are also an opportunity to distinguish > > real _unit_ style tests and then the rarer integration-style tests. I > > personally prefer using the more generic *-test.c, at least for the > > integration-style tests I've been working on (KUnit is still incredibly > > valuable for integration-style tests, because otherwise I'd have to roll > > my own poor-man's version of KUnit, so thank you!). Using *_kunit.c for > > such tests is unintuitive, because the word "unit" hints at "unit tests" > > -- and having descriptive (and not misleading) filenames is still > > important. So I hope you won't mind if *-test.c are still used where > > appropriate. > > As Brendan alluded to in the talk, the popularity of KUnit for these > integration-style tests came as something of a surprise (more due to > our lack of imagination than anything else, I suspect). It's great > that it's working, though: I don't think anyone wants the world filled > with more single-use test "frameworks" than is necessary! > > I guess the interesting thing to note is that we've to date not really > made a distinction between KUnit the framework and the suite of all > KUnit tests. Maybe having a separate file/module naming scheme could > be a way of making that distinction, though it'd really only appear > when loading tests as modules -- there'd be no indication in e.g., > suite names or test results. The more obvious solution to me (at > least, based on the current proposal) would be to have "integration" > or similar be part of the suite name (and hence the filename, so > _integration_kunit.c or similar), though even I admit that that's much > uglier. Yeah, that's not great either. Again, in the end it's probably entirely up to you, but it'd be good if the filenames are descriptive and readable (vs. a puzzle). > Maybe the idea of having the subsystem/suite distinction be > represented in the code could pave the way to having different suites > support different suffixes like that. > Do you know of any cases where something has/would have both > unit-style tests and integration-style tests built with KUnit where > the distinction needs to be clear? None I know of, so probably not a big deal. > Brendan, Kees: do you have any thoughts? > > Cheers, > -- David Thanks, -- Marco