From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on archive.lwn.net X-Spam-Level: X-Spam-Status: No, score=-13.3 required=5.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI,SPF_HELO_NONE,SPF_NONE, USER_IN_DEF_DKIM_WL autolearn=unavailable autolearn_force=no version=3.4.2 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by archive.lwn.net (Postfix) with ESMTP id E83DE7D912 for ; Wed, 17 Jul 2019 01:58:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725907AbfGQBzy (ORCPT ); Tue, 16 Jul 2019 21:55:54 -0400 Received: from mail-pf1-f201.google.com ([209.85.210.201]:45221 "EHLO mail-pf1-f201.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725906AbfGQBzx (ORCPT ); Tue, 16 Jul 2019 21:55:53 -0400 Received: by mail-pf1-f201.google.com with SMTP id i27so13502454pfk.12 for ; Tue, 16 Jul 2019 18:55:53 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:message-id:mime-version:subject:from:to:cc; bh=g73VbK9hP8iwHcV/w0DEWc6A8T81W2obxVf/JscQhPY=; b=Vbb6ETWdoL7/dyTwrtnSjUAJji8HmC0dbYlvBQhYL3ZtcFa53MTUkxRV21Vh+xQzRU gtcMrgV6CsUcmCq6PHa2QI2RapBr3kPi3qcDZTk/V+RQINbCgIAGW9XgyyKfzkIP+4A2 Cj9ApaRpGtUkElZpxENbPQ4y/LhEkO32Y8s6YtL6EobTN8efWAzcypCT1B1B2UtD/u4i A3n0+WeJDp01P7yO5hdDAfarVytQtTxJ7QrOXdADRb4dC2e7V8+WsZndPYZvAMZpQ4s7 2BclIo1VrtBu6iu7lEVSZ2YJI8piqhPI0Z2qIl5B2wcZ4ToCguieuFOeyAl4qvN2wNXh HDVg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:message-id:mime-version:subject:from:to:cc; bh=g73VbK9hP8iwHcV/w0DEWc6A8T81W2obxVf/JscQhPY=; b=linZiXL+UMYEP3MFXO9m4d4H3RKIY7SyLakFzmbn7Ic/77idbDZ1ESiTjUjzDRJrIe Pc1V9kDg51BRydPaxSOh1H4HNGC+qcARRe6mMWKzH2mVl4VmGPIXBPDnVQ6NWH82zyp4 cwL00mXceeFfpER0HyHjday53UL1C9FyVGNJ5Pvm+xOhL9o9pFird3pJ0v8dj/0cbYE8 zGnfdfez9nhMHcFU5YdcmqQY34jRhvOhgrVr4RaLIfhkbQAW/4KX6QC30lX7atTznynT TSJFgmYtoxqJsG2UZA3zs8XUKBF49AIgU258MC6zELFmSv20Gpmjc4RwI0VXY5y7ppwc iMVA== X-Gm-Message-State: APjAAAVTXuifwb22S8gt/z8R2TA0zPwB6MxbifKvMAaVqEfOsz4uZLfE YRSF8u0H5aRZzYaiqwnRVdTMCka2O/6cgC23gm1N9g== X-Google-Smtp-Source: APXvYqzIJkjKQ3S+2BDLj5Fx/7Xa9wrPBuZpZW0wEdv7tjBDXndxr0psGCLPsqNbiarNlPEHuGD5doQNqhtuO1IsifVYng== X-Received: by 2002:a63:2606:: with SMTP id m6mr37469748pgm.436.1563328552353; Tue, 16 Jul 2019 18:55:52 -0700 (PDT) Date: Tue, 16 Jul 2019 18:55:25 -0700 Message-Id: <20190717015543.152251-1-brendanhiggins@google.com> Mime-Version: 1.0 X-Mailer: git-send-email 2.22.0.510.g264f2c817a-goog Subject: [PATCH v11 00/18] kunit: introduce KUnit, the Linux kernel unit testing framework From: Brendan Higgins To: frowand.list@gmail.com, gregkh@linuxfoundation.org, jpoimboe@redhat.com, keescook@google.com, kieran.bingham@ideasonboard.com, mcgrof@kernel.org, peterz@infradead.org, robh@kernel.org, sboyd@kernel.org, shuah@kernel.org, tytso@mit.edu, yamada.masahiro@socionext.com Cc: devicetree@vger.kernel.org, dri-devel@lists.freedesktop.org, kunit-dev@googlegroups.com, linux-doc@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-nvdimm@lists.01.org, linux-um@lists.infradead.org, Alexander.Levin@microsoft.com, Tim.Bird@sony.com, amir73il@gmail.com, dan.carpenter@oracle.com, daniel@ffwll.ch, jdike@addtoit.com, joel@jms.id.au, julia.lawall@lip6.fr, khilman@baylibre.com, knut.omang@oracle.com, logang@deltatee.com, mpe@ellerman.id.au, pmladek@suse.com, rdunlap@infradead.org, richard@nod.at, rientjes@google.com, rostedt@goodmis.org, wfg@linux.intel.com, Brendan Higgins , Michal Marek , Jonathan Corbet , Iurii Zaikin Content-Type: text/plain; charset="UTF-8" Sender: linux-doc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org ## TL;DR This patchset addresses comments from Stephen Boyd. No changes affect the API, and all changes are specific to patches 02, 03, and 04; however, there were some significant changes to how string_stream and kunit_stream work under the hood. ## Background This patch set proposes KUnit, a lightweight unit testing and mocking framework for the Linux kernel. Unlike Autotest and kselftest, KUnit is a true unit testing framework; it does not require installing the kernel on a test machine or in a VM (however, KUnit still allows you to run tests on test machines or in VMs if you want[1]) and does not require tests to be written in userspace running on a host kernel. Additionally, KUnit is fast: From invocation to completion KUnit can run several dozen tests in about a second. Currently, the entire KUnit test suite for KUnit runs in under a second from the initial invocation (build time excluded). KUnit is heavily inspired by JUnit, Python's unittest.mock, and Googletest/Googlemock for C++. KUnit provides facilities for defining unit test cases, grouping related test cases into test suites, providing common infrastructure for running tests, mocking, spying, and much more. ### What's so special about unit testing? A unit test is supposed to test a single unit of code in isolation, hence the name. There should be no dependencies outside the control of the test; this means no external dependencies, which makes tests orders of magnitudes faster. Likewise, since there are no external dependencies, there are no hoops to jump through to run the tests. Additionally, this makes unit tests deterministic: a failing unit test always indicates a problem. Finally, because unit tests necessarily have finer granularity, they are able to test all code paths easily solving the classic problem of difficulty in exercising error handling code. ### Is KUnit trying to replace other testing frameworks for the kernel? No. Most existing tests for the Linux kernel are end-to-end tests, which have their place. A well tested system has lots of unit tests, a reasonable number of integration tests, and some end-to-end tests. KUnit is just trying to address the unit test space which is currently not being addressed. ### More information on KUnit There is a bunch of documentation near the end of this patch set that describes how to use KUnit and best practices for writing unit tests. For convenience I am hosting the compiled docs here[2]. Additionally for convenience, I have applied these patches to a branch[3]. The repo may be cloned with: git clone https://kunit.googlesource.com/linux This patchset is on the kunit/rfc/v5.2/v11 branch. ## Changes Since Last Version - Went back to using spinlock in `struct string_stream`. Needed for so that it is compatible with different GFP flags to address comment from Stephen. - Added string_stream_append function to string_stream API. - suggested by Stephen. - Made all string fragments and other allocations internal to string_stream and kunit_stream managed by the KUnit resource management API. [1] https://google.github.io/kunit-docs/third_party/kernel/docs/usage.html#kunit-on-non-uml-architectures [2] https://google.github.io/kunit-docs/third_party/kernel/docs/ [3] https://kunit.googlesource.com/linux/+/kunit/rfc/v5.2/v11 -- 2.22.0.510.g264f2c817a-goog