From patchwork Fri Nov 11 18:29:04 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Daniel Latypov X-Patchwork-Id: 624108 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 59FC8C46467 for ; Fri, 11 Nov 2022 18:30:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234129AbiKKS3i (ORCPT ); Fri, 11 Nov 2022 13:29:38 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33398 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234145AbiKKS30 (ORCPT ); Fri, 11 Nov 2022 13:29:26 -0500 Received: from mail-pj1-x104a.google.com (mail-pj1-x104a.google.com [IPv6:2607:f8b0:4864:20::104a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 551975CD11 for ; Fri, 11 Nov 2022 10:29:25 -0800 (PST) Received: by mail-pj1-x104a.google.com with SMTP id o15-20020a17090aac0f00b00212e93524c0so5844493pjq.2 for ; Fri, 11 Nov 2022 10:29:25 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=cc:to:from:subject:message-id:mime-version:date:from:to:cc:subject :date:message-id:reply-to; bh=/XHe3/zCTpZWNceRA9RtU7Jdjy85jUuF1PtTziDeOJ4=; b=SHWYMQw6kstMFCPeHdhZKyPK3U1w2EOYu+EfQeWTuTi4NJieEMZil99CRywaRL3QXr M7ApzG4XLCYAg0PetxNjHSfwNLA3LxmKu8LWDFygNY1lctOOSshYpwuhWdWdEPG4cj6h QWqck+Cp18gxDExvnjGBgUh7CGuL123P/8Sic7xH/4xHFrfRq9PyO6QZDjJ4xQ81rw8G Mj7r+mHBVner9YkXBqCGbX7sD3i/SJKHNJEtf9od3zBTOZpkh1OElZCPLXu9Kh0yHr+g 5EMsCruUmvhnGFsKUm63rt7fbbaTOV3YvxO7RSu0ufBKSPyJZYCW9ZnNfdCPxDuX08e5 qhGA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:from:subject:message-id:mime-version:date:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=/XHe3/zCTpZWNceRA9RtU7Jdjy85jUuF1PtTziDeOJ4=; b=gurh+D8Uwm+95WyP18uYtESjCrodeP8JcNfNoKOh5r+eJQzoJ5fHZ1UzHO3cBI/xT3 hcWPELfz4+xQaR1gjSlbmu/pLXsarIDBt7636fvlOYxM+c4efVkLZuWKOfYHKidCm9ej ShAmAThKE9DE6W9tYoiAAy0JraQqcFs7AilpZ2Z1e0Ftp+/Am5xauXHTcKdK0r8QJxbq 9Pb9XMPd7yxlOGUynt5Xw84SemfQ6uXi35+ioMV7avJ1nnfnGguEmFB+0nfnLsdMjcp0 VSgGS5MSj/NY5EvBO4DYm5kY0bHz/LBjxp56zFispIR1cwHb2FIvijV2LxuteT5q/4T+ vYyg== X-Gm-Message-State: ANoB5pmf/8C5vSTdxwiUCJSjJA9OJh7sUjS2L91nyNumkMhHDGugUApy v+SCoCDQCAC888FDkWBJsmAnKiQ735abUA== X-Google-Smtp-Source: AA0mqf6oRQTd26j/7lMqh+0QrNTk7PgW/u/hbIVY7qUTrqiyiF7iitQQrLw0zJAXHQI4fYDQUXP1Ip5tvZZY/g== X-Received: from dlatypov-spec.c.googlers.com ([fda3:e722:ac3:cc00:24:72f4:c0a8:3f35]) (user=dlatypov job=sendgmr) by 2002:a17:90a:d01:b0:20a:fee1:8f69 with SMTP id t1-20020a17090a0d0100b0020afee18f69mr7707pja.0.1668191364606; Fri, 11 Nov 2022 10:29:24 -0800 (PST) Date: Fri, 11 Nov 2022 10:29:04 -0800 Mime-Version: 1.0 X-Mailer: git-send-email 2.38.1.431.g37b22c650d-goog Message-ID: <20221111182906.1377191-1-dlatypov@google.com> Subject: [PATCH v3 1/3] Documentation: KUnit: make usage.rst a superset of tips.rst, remove duplication From: Daniel Latypov To: brendanhiggins@google.com, davidgow@google.com Cc: rmoar@google.com, linux-kernel@vger.kernel.org, kunit-dev@googlegroups.com, linux-kselftest@vger.kernel.org, linux-doc@vger.kernel.org, skhan@linuxfoundation.org, Daniel Latypov , Sadiya Kazi Precedence: bulk List-ID: X-Mailing-List: linux-kselftest@vger.kernel.org usage.rst had most of the content of the tips.rst page copied over. But it's missing https://www.kernel.org/doc/html/v6.0/dev-tools/kunit/tips.html#customizing-error-messages Copy it over so we can retire tips.rst w/o losing content. And in that process, it also gained a duplicate section about how KUNIT_ASSERT_*() exit the test case early. Remove that. Signed-off-by: Daniel Latypov Reviewed-by: Sadiya Kazi Reviewed-by: David Gow --- Documentation/dev-tools/kunit/usage.rst | 49 ++++++++++++++++--------- 1 file changed, 31 insertions(+), 18 deletions(-) base-commit: 870f63b7cd78d0055902d839a60408f7428b4e84 diff --git a/Documentation/dev-tools/kunit/usage.rst b/Documentation/dev-tools/kunit/usage.rst index 2737863ef365..b0a6c3bc0eeb 100644 --- a/Documentation/dev-tools/kunit/usage.rst +++ b/Documentation/dev-tools/kunit/usage.rst @@ -118,6 +118,37 @@ expectation could crash the test case. `ASSERT_NOT_ERR_OR_NULL(...)` allows us to bail out of the test case if the appropriate conditions are not satisfied to complete the test. +Customizing error messages +-------------------------- + +Each of the ``KUNIT_EXPECT`` and ``KUNIT_ASSERT`` macros have a ``_MSG`` +variant. These take a format string and arguments to provide additional +context to the automatically generated error messages. + +.. code-block:: c + + char some_str[41]; + generate_sha1_hex_string(some_str); + + /* Before. Not easy to tell why the test failed. */ + KUNIT_EXPECT_EQ(test, strlen(some_str), 40); + + /* After. Now we see the offending string. */ + KUNIT_EXPECT_EQ_MSG(test, strlen(some_str), 40, "some_str='%s'", some_str); + +Alternatively, one can take full control over the error message by using +``KUNIT_FAIL()``, e.g. + +.. code-block:: c + + /* Before */ + KUNIT_EXPECT_EQ(test, some_setup_function(), 0); + + /* After: full control over the failure message. */ + if (some_setup_function()) + KUNIT_FAIL(test, "Failed to setup thing for testing"); + + Test Suites ~~~~~~~~~~~ @@ -546,24 +577,6 @@ By reusing the same ``cases`` array from above, we can write the test as a {} }; -Exiting Early on Failed Expectations ------------------------------------- - -We can use ``KUNIT_EXPECT_EQ`` to mark the test as failed and continue -execution. In some cases, it is unsafe to continue. We can use the -``KUNIT_ASSERT`` variant to exit on failure. - -.. code-block:: c - - void example_test_user_alloc_function(struct kunit *test) - { - void *object = alloc_some_object_for_me(); - - /* Make sure we got a valid pointer back. */ - KUNIT_ASSERT_NOT_ERR_OR_NULL(test, object); - do_something_with_object(object); - } - Allocating Memory ----------------- From patchwork Fri Nov 11 18:29:05 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Daniel Latypov X-Patchwork-Id: 624109 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 492BBC38A02 for ; Fri, 11 Nov 2022 18:30:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234018AbiKKS3i (ORCPT ); Fri, 11 Nov 2022 13:29:38 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33414 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234160AbiKKS31 (ORCPT ); Fri, 11 Nov 2022 13:29:27 -0500 Received: from mail-pj1-x104a.google.com (mail-pj1-x104a.google.com [IPv6:2607:f8b0:4864:20::104a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0EB5A5B5A7 for ; Fri, 11 Nov 2022 10:29:27 -0800 (PST) Received: by mail-pj1-x104a.google.com with SMTP id pq17-20020a17090b3d9100b0020a4c65c3a9so3105432pjb.0 for ; Fri, 11 Nov 2022 10:29:27 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=KcgFgh+nSA6rGpYyKLAuOEZq9MjORsirblL9B+ChLi0=; b=GN/K8LkzrC3Xi5m04YE/88CUGXGI57CIBf0CroPXanf1c2e6S7KaF1zLqjHRHaJxTx GjvPAk0vMcz6bA+Z4e5AcNtwS8mrZeHu5LV1+rn9AUJ2buoMWZLYzv9ZOeqx8p90AClW d6tTK9BSyqanwQ7lWbOgSTQgzJu5hJc6k6RH4Umsl2iyoKEsZeEo3LWxKjJAeFlbRGdn t2T0hO+T2pQQWkpLB6mpYhu5eIgLgYbYKfQyVBtJ2LKCmwARyFYbzrW+mPnt/8U1HCuE vfvziKXdQL3Iy3zXYcXgXULs2DiskUzS69Uezt504J3TOKAHeIuvc8XiNQcxhonzGESx 1eoQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=KcgFgh+nSA6rGpYyKLAuOEZq9MjORsirblL9B+ChLi0=; b=2/dvlX3S62uYqx+iEMfdn7JpJUvlMx4N28wHqrqg72CTVYB6rlhA065qKlChoxFV90 wzXOFI0qfwtSkWfBbONd5IqhKexcpZWFOawKVGTS7gCVFDXc/GoYEDNLb/6GrearLCB3 6ETOyHqDnlzW2EihPIFppuGTxmhv9uZZUxO4mkzREQqsbm9cDNSCyF40l7PwQiUWZfWi fXidjdtrG16SWTDg1nrsVzHVbZHcVcx5wHpbFsovgyU4CIxxpLG7eYva7KdysY9MP83l xMQSXAZWrpCG08Z5viXvdKK+5oUzBzWxkBdJN3U7ZKR+X7ZKFBqtCBsRTAUQJ1fObpJF MLvQ== X-Gm-Message-State: ANoB5pndshYPzS9R2uoxG4bycLd3JAdJ6ojCMHCVZKBd8YRbXRf0qjHD azNWxTS1Zwl4flm8uuzNaQi/+kckP+cFhw== X-Google-Smtp-Source: AA0mqf4NpCqVqQb5VhOoQGCCFX1K81V4IUVGkY7iGc1jDIwrgceDHzDGMr97O9zfwN+WASG6WpOvW/XDWu9a6w== X-Received: from dlatypov-spec.c.googlers.com ([fda3:e722:ac3:cc00:24:72f4:c0a8:3f35]) (user=dlatypov job=sendgmr) by 2002:a17:902:9302:b0:187:3a43:3a9d with SMTP id bc2-20020a170902930200b001873a433a9dmr3593182plb.152.1668191366583; Fri, 11 Nov 2022 10:29:26 -0800 (PST) Date: Fri, 11 Nov 2022 10:29:05 -0800 In-Reply-To: <20221111182906.1377191-1-dlatypov@google.com> Mime-Version: 1.0 References: <20221111182906.1377191-1-dlatypov@google.com> X-Mailer: git-send-email 2.38.1.431.g37b22c650d-goog Message-ID: <20221111182906.1377191-2-dlatypov@google.com> Subject: [PATCH v3 2/3] Documentation: KUnit: reword description of assertions From: Daniel Latypov To: brendanhiggins@google.com, davidgow@google.com Cc: rmoar@google.com, linux-kernel@vger.kernel.org, kunit-dev@googlegroups.com, linux-kselftest@vger.kernel.org, linux-doc@vger.kernel.org, skhan@linuxfoundation.org, Daniel Latypov , Sadiya Kazi Precedence: bulk List-ID: X-Mailing-List: linux-kselftest@vger.kernel.org The existing wording implies that kunit_kmalloc_array() is "the method under test". We're actually testing the sort() function in that example. This is because the example was changed in commit 953574390634 ("Documentation: KUnit: Rework writing page to focus on writing tests"), but the wording was not. Also add a `note` telling people they can use the KUNIT_ASSERT_EQ() macros from any function. Some users might be coming from a framework like gUnit where that'll compile but silently do the wrong thing. Signed-off-by: Daniel Latypov Reviewed-by: Sadiya Kazi Reviewed-by: David Gow --- Documentation/dev-tools/kunit/usage.rst | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-) diff --git a/Documentation/dev-tools/kunit/usage.rst b/Documentation/dev-tools/kunit/usage.rst index b0a6c3bc0eeb..22416ebb94ab 100644 --- a/Documentation/dev-tools/kunit/usage.rst +++ b/Documentation/dev-tools/kunit/usage.rst @@ -112,11 +112,14 @@ terminates the test case if the condition is not satisfied. For example: KUNIT_EXPECT_LE(test, a[i], a[i + 1]); } -In this example, the method under test should return pointer to a value. If the -pointer returns null or an errno, we want to stop the test since the following -expectation could crash the test case. `ASSERT_NOT_ERR_OR_NULL(...)` allows us -to bail out of the test case if the appropriate conditions are not satisfied to -complete the test. +In this example, we need to be able to allocate an array to test the ``sort()`` +function. So we use ``KUNIT_ASSERT_NOT_ERR_OR_NULL()`` to abort the test if +there's an allocation error. + +.. note:: + In other test frameworks, ``ASSERT`` macros are often implemented by calling + ``return`` so they only work from the test function. In KUnit, we stop the + current kthread on failure, so you can call them from anywhere. Customizing error messages -------------------------- From patchwork Fri Nov 11 18:29:06 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Daniel Latypov X-Patchwork-Id: 624336 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6FCE4C3A59E for ; Fri, 11 Nov 2022 18:30:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234161AbiKKS3j (ORCPT ); Fri, 11 Nov 2022 13:29:39 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33438 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234178AbiKKS3b (ORCPT ); Fri, 11 Nov 2022 13:29:31 -0500 Received: from mail-yw1-x1149.google.com (mail-yw1-x1149.google.com [IPv6:2607:f8b0:4864:20::1149]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 748E55CD01 for ; Fri, 11 Nov 2022 10:29:29 -0800 (PST) Received: by mail-yw1-x1149.google.com with SMTP id 00721157ae682-3697bd55974so50750047b3.15 for ; Fri, 11 Nov 2022 10:29:29 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=r84PG1jgHBipBYlbDtpXYn0KfCJQRPPV8o0t+BC7r80=; b=RTy2mC0LwDZH56aX/w5OhguMBUe0+J5NWLoqXauoT3IvbjP/GZvP1lp3Ift6APPArw S0endsxM2v7avWGZ+xCuwXUGDN1LUVmi91L7dhjt+htx7KxAGxyNOFM7nD2b5cV9Gjet buNVVDzwkcV0nD4TURr1q/Yb95l5qlwiHrXiN1Wa5ZSlFNtuhxnJZ+it6EZo//YgJeik FE+LS07QdGQf7NGbEIgl3UI5l28xphpdu91FyM0N5oN+V6awlfOCHo16TYQtqzA0GQ7I yz623pljBCpZ0pOe/hhh3r7I+V3xhKWBdS4NYzn+am8dRY/ZDPkW2jqT444VqZ7G5oFX 0AUw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=r84PG1jgHBipBYlbDtpXYn0KfCJQRPPV8o0t+BC7r80=; b=RUG+hvJD48I2zMCwUhIMbkQKHutRWM04BSofU1hwkfDsLl+pPQlTZTqO/15I1Hzpuj cn0+/TRhkHZLCwhu8N4B0y1rq2saVgScCF7XcVf6FdG0dAA+Kau2fN3mKkcZ31YAQP4F lpJyQghBM4Inz5VGbm1QCEP7JRCxTeOELCn0ry2TQNrEvDXhPDxxU/s+GL0B4A5vO+oT rF5QXQN/H/mLjbgsRsdSPXA1/TJuHZDbVp+9kYu6wUwSOxLYqoStZei5afYdkLWf5HCq QPw0egwJE4cyVAVWj35IB3NXOyItKnKfl3TgBNIKjuocuhi8PLBh5dNuES/v6YJ1OEQR k9BA== X-Gm-Message-State: ACrzQf32+aEntRdQVyMPInAJ1A2iCduWSCA96t+QfyNx7M7ZdWPJo+HY oum7LefnKoZ9dPUv4V9KD8gRv80QDMGlRA== X-Google-Smtp-Source: AMsMyM5gX6MRToLN85JAmPfGGO3zA2+D/4SmfJVxgoEu/EYsQQaI5mVzMkNQzf6jmQcMK68t0u9cNyV/pHbppg== X-Received: from dlatypov-spec.c.googlers.com ([fda3:e722:ac3:cc00:24:72f4:c0a8:3f35]) (user=dlatypov job=sendgmr) by 2002:a81:5d7:0:b0:367:300a:b24a with SMTP id 206-20020a8105d7000000b00367300ab24amr65639713ywf.128.1668191368372; Fri, 11 Nov 2022 10:29:28 -0800 (PST) Date: Fri, 11 Nov 2022 10:29:06 -0800 In-Reply-To: <20221111182906.1377191-1-dlatypov@google.com> Mime-Version: 1.0 References: <20221111182906.1377191-1-dlatypov@google.com> X-Mailer: git-send-email 2.38.1.431.g37b22c650d-goog Message-ID: <20221111182906.1377191-3-dlatypov@google.com> Subject: [PATCH v3 3/3] Documentation: kunit: Remove redundant 'tips.rst' page From: Daniel Latypov To: brendanhiggins@google.com, davidgow@google.com Cc: rmoar@google.com, linux-kernel@vger.kernel.org, kunit-dev@googlegroups.com, linux-kselftest@vger.kernel.org, linux-doc@vger.kernel.org, skhan@linuxfoundation.org, Daniel Latypov , Sadiya Kazi Precedence: bulk List-ID: X-Mailing-List: linux-kselftest@vger.kernel.org From: David Gow The contents of 'tips.rst' was mostly included in 'usage.rst' way back in commit 953574390634 ("Documentation: KUnit: Rework writing page to focus on writing tests"), but the tips page remained behind as well. The parent patches in this series fill in the gaps, so now 'tips.rst' is redundant. Therefore, delete 'tips.rst'. While I regret breaking any links to 'tips' which might exist externally, it's confusing to have two subtly different versions of the same content around. Signed-off-by: David Gow Signed-off-by: Daniel Latypov Reviewed-by: Sadiya Kazi --- v1 -> v2: rebased onto some parent patches to fix the missing sections in usage.rst and tweaked the commit message to reflect that. --- Documentation/dev-tools/kunit/index.rst | 1 - Documentation/dev-tools/kunit/tips.rst | 190 ------------------------ 2 files changed, 191 deletions(-) delete mode 100644 Documentation/dev-tools/kunit/tips.rst diff --git a/Documentation/dev-tools/kunit/index.rst b/Documentation/dev-tools/kunit/index.rst index f5d13f1d37be..d5629817cd72 100644 --- a/Documentation/dev-tools/kunit/index.rst +++ b/Documentation/dev-tools/kunit/index.rst @@ -16,7 +16,6 @@ KUnit - Linux Kernel Unit Testing api/index style faq - tips running_tips This section details the kernel unit testing framework. diff --git a/Documentation/dev-tools/kunit/tips.rst b/Documentation/dev-tools/kunit/tips.rst deleted file mode 100644 index 492d2ded2f5a..000000000000 --- a/Documentation/dev-tools/kunit/tips.rst +++ /dev/null @@ -1,190 +0,0 @@ -.. SPDX-License-Identifier: GPL-2.0 - -============================ -Tips For Writing KUnit Tests -============================ - -Exiting early on failed expectations ------------------------------------- - -``KUNIT_EXPECT_EQ`` and friends will mark the test as failed and continue -execution. In some cases, it's unsafe to continue and you can use the -``KUNIT_ASSERT`` variant to exit on failure. - -.. code-block:: c - - void example_test_user_alloc_function(struct kunit *test) - { - void *object = alloc_some_object_for_me(); - - /* Make sure we got a valid pointer back. */ - KUNIT_ASSERT_NOT_ERR_OR_NULL(test, object); - do_something_with_object(object); - } - -Allocating memory ------------------ - -Where you would use ``kzalloc``, you should prefer ``kunit_kzalloc`` instead. -KUnit will ensure the memory is freed once the test completes. - -This is particularly useful since it lets you use the ``KUNIT_ASSERT_EQ`` -macros to exit early from a test without having to worry about remembering to -call ``kfree``. - -Example: - -.. code-block:: c - - void example_test_allocation(struct kunit *test) - { - char *buffer = kunit_kzalloc(test, 16, GFP_KERNEL); - /* Ensure allocation succeeded. */ - KUNIT_ASSERT_NOT_ERR_OR_NULL(test, buffer); - - KUNIT_ASSERT_STREQ(test, buffer, ""); - } - - -Testing static functions ------------------------- - -If you don't want to expose functions or variables just for testing, one option -is to conditionally ``#include`` the test file at the end of your .c file, e.g. - -.. code-block:: c - - /* In my_file.c */ - - static int do_interesting_thing(); - - #ifdef CONFIG_MY_KUNIT_TEST - #include "my_kunit_test.c" - #endif - -Injecting test-only code ------------------------- - -Similarly to the above, it can be useful to add test-specific logic. - -.. code-block:: c - - /* In my_file.h */ - - #ifdef CONFIG_MY_KUNIT_TEST - /* Defined in my_kunit_test.c */ - void test_only_hook(void); - #else - void test_only_hook(void) { } - #endif - -This test-only code can be made more useful by accessing the current kunit -test, see below. - -Accessing the current test --------------------------- - -In some cases, you need to call test-only code from outside the test file, e.g. -like in the example above or if you're providing a fake implementation of an -ops struct. -There is a ``kunit_test`` field in ``task_struct``, so you can access it via -``current->kunit_test``. - -Here's a slightly in-depth example of how one could implement "mocking": - -.. code-block:: c - - #include /* for current */ - - struct test_data { - int foo_result; - int want_foo_called_with; - }; - - static int fake_foo(int arg) - { - struct kunit *test = current->kunit_test; - struct test_data *test_data = test->priv; - - KUNIT_EXPECT_EQ(test, test_data->want_foo_called_with, arg); - return test_data->foo_result; - } - - static void example_simple_test(struct kunit *test) - { - /* Assume priv is allocated in the suite's .init */ - struct test_data *test_data = test->priv; - - test_data->foo_result = 42; - test_data->want_foo_called_with = 1; - - /* In a real test, we'd probably pass a pointer to fake_foo somewhere - * like an ops struct, etc. instead of calling it directly. */ - KUNIT_EXPECT_EQ(test, fake_foo(1), 42); - } - - -Note: here we're able to get away with using ``test->priv``, but if you wanted -something more flexible you could use a named ``kunit_resource``, see -Documentation/dev-tools/kunit/api/test.rst. - -Failing the current test ------------------------- - -But sometimes, you might just want to fail the current test. In that case, we -have ``kunit_fail_current_test(fmt, args...)`` which is defined in ```` and -doesn't require pulling in ````. - -E.g. say we had an option to enable some extra debug checks on some data structure: - -.. code-block:: c - - #include - - #ifdef CONFIG_EXTRA_DEBUG_CHECKS - static void validate_my_data(struct data *data) - { - if (is_valid(data)) - return; - - kunit_fail_current_test("data %p is invalid", data); - - /* Normal, non-KUnit, error reporting code here. */ - } - #else - static void my_debug_function(void) { } - #endif - - -Customizing error messages --------------------------- - -Each of the ``KUNIT_EXPECT`` and ``KUNIT_ASSERT`` macros have a ``_MSG`` variant. -These take a format string and arguments to provide additional context to the automatically generated error messages. - -.. code-block:: c - - char some_str[41]; - generate_sha1_hex_string(some_str); - - /* Before. Not easy to tell why the test failed. */ - KUNIT_EXPECT_EQ(test, strlen(some_str), 40); - - /* After. Now we see the offending string. */ - KUNIT_EXPECT_EQ_MSG(test, strlen(some_str), 40, "some_str='%s'", some_str); - -Alternatively, one can take full control over the error message by using ``KUNIT_FAIL()``, e.g. - -.. code-block:: c - - /* Before */ - KUNIT_EXPECT_EQ(test, some_setup_function(), 0); - - /* After: full control over the failure message. */ - if (some_setup_function()) - KUNIT_FAIL(test, "Failed to setup thing for testing"); - -Next Steps -========== -* Optional: see the Documentation/dev-tools/kunit/usage.rst page for a more - in-depth explanation of KUnit.