From patchwork Wed Nov 9 00:36:16 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Daniel Latypov X-Patchwork-Id: 13037001 X-Patchwork-Delegate: brendanhiggins@google.com 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 A178BC4332F for ; Wed, 9 Nov 2022 00:36:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229622AbiKIAg1 (ORCPT ); Tue, 8 Nov 2022 19:36:27 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37806 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229508AbiKIAg1 (ORCPT ); Tue, 8 Nov 2022 19:36:27 -0500 Received: from mail-pl1-x649.google.com (mail-pl1-x649.google.com [IPv6:2607:f8b0:4864:20::649]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6BDA263153 for ; Tue, 8 Nov 2022 16:36:26 -0800 (PST) Received: by mail-pl1-x649.google.com with SMTP id h16-20020a170902f55000b001871b770a83so12174555plf.9 for ; Tue, 08 Nov 2022 16:36:26 -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=CZKNxZ4ut/Q7ACsrFTYtA5PMiQEhI2gWEXdAM+wb9gg=; b=cYSLYVLkoMHuam5SuetiF8cgGiYoAYiOA1FDE0de+JVwbInSf58Fn7Nuqba7t29Tlm kAEkRJI243IEl56URLz4GqhHzc5kNIoyBU5dolJ68qRmCHxVduAFhPFH9sXXHt7fsP2m wmOYn67OQtdmCCrHj+8T+iKeAM2KzgvXbTWuWou/qcNVuehaO2UQIl6x966q4q7Z8zpd Ngq+YURUPwM23Bk/LkbCwHiBmOToe4IyoOidBtQN8lPzxQ470F5rRAwMWnq3T1F7EKp0 isviHND/AkHcHu1qZfF96e0YUSkLT9d59G44rU/vjx0VWjDPLr9E1T9TmfaZIhC402Jc UqQg== 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=CZKNxZ4ut/Q7ACsrFTYtA5PMiQEhI2gWEXdAM+wb9gg=; b=xkLVeHZG0LTiLEZ3rY+t+I8gA0FWItd0vKf4x4+CTw0ACLG1/XRqtbXUhSptsCm6g9 mGQLV9s0apLLd3BWh/Z267EbbXggww60VEU3rKwixH4o9vLempstBpYHxEOlCEOeJTrS LPygh/vJFpOOLDhKlrb1tna0x13Ex0Xzz/xw3edd6l4o3+ojFl53EKISMit9TfADbsGJ aJr8MD+GEFRpuPneddnGBgear1Gw5HkDi5QaICWfr3vVuBqVESaAdbvTylGD8O0MPbpl C2acS1qeSnaX31l8iY2xrgOqeyFqR3fgyNgtzncL84ba3pc1pRPQLqcMVKMTjOPIesbm j8nQ== X-Gm-Message-State: ACrzQf2xMCFIhP7gvJCcmV0Bq7x9MUjKtJsE7yJO2QsMJ+CIHoLrJtVd RVzgYdko8jUl9tFdrTKn/viHBQoUsaSSsA== X-Google-Smtp-Source: AMsMyM5l1InG0bHkfyqtHlCsU7XWX0gLXIAXXCROhFBi9h+H8VfW0HVhDGCUeTz7B6sT1CNJ/zoHWriib5mDQw== X-Received: from dlatypov-spec.c.googlers.com ([fda3:e722:ac3:cc00:24:72f4:c0a8:3f35]) (user=dlatypov job=sendgmr) by 2002:a17:90a:f3d4:b0:213:959f:5a90 with SMTP id ha20-20020a17090af3d400b00213959f5a90mr63952761pjb.54.1667954185985; Tue, 08 Nov 2022 16:36:25 -0800 (PST) Date: Tue, 8 Nov 2022 16:36:16 -0800 Mime-Version: 1.0 X-Mailer: git-send-email 2.38.1.431.g37b22c650d-goog Message-ID: <20221109003618.3784591-1-dlatypov@google.com> Subject: [PATCH v2 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 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 --- Documentation/dev-tools/kunit/usage.rst | 49 ++++++++++++++++--------- 1 file changed, 31 insertions(+), 18 deletions(-) base-commit: 6fe1ad4a156095859721fef85073df3ed43081d4 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 Wed Nov 9 00:36:17 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Daniel Latypov X-Patchwork-Id: 13037002 X-Patchwork-Delegate: brendanhiggins@google.com 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 7C719C43217 for ; Wed, 9 Nov 2022 00:36:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229868AbiKIAg3 (ORCPT ); Tue, 8 Nov 2022 19:36:29 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37826 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229621AbiKIAg2 (ORCPT ); Tue, 8 Nov 2022 19:36:28 -0500 Received: from mail-pl1-x64a.google.com (mail-pl1-x64a.google.com [IPv6:2607:f8b0:4864:20::64a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4068C627D1 for ; Tue, 8 Nov 2022 16:36:28 -0800 (PST) Received: by mail-pl1-x64a.google.com with SMTP id b2-20020a170902d50200b001871a3c51afso12157098plg.8 for ; Tue, 08 Nov 2022 16:36:28 -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=i16E6SEJ1XE3RexrHSv+UKrQKUgWn1ksElBhVAhWC74=; b=ozndvYKnYfbi79PbuCYdzeMtofBcdWRIc10S48fA0ZiNj/LbcnyA78EeEyHbGlu9n6 7J9OUUeOSTjZdMHJ2Jj8jMxpE5/dNiSdsErzggvwEEW2nUjxnCa6+TDqTkoDJz9gOj99 WXadIIjgvnxIVJ/DBFiBgHJkkWlKthceyqDaVjg9MiPmZqLDPR9LHxZsOGuMW6BjHu/c 3eJf90rCsgm0AwbOvUrB59Y/Jmt+M8z3+xf8wujZCxWlDqOqjDioHBcPrSHS2jcF5xIG mcVvtHsOwHn5TgP74M+8eZTB81t5B4R9Xo69adh1fUPMDntg2alkPx9VTHycCQY1TfJc Zpeg== 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=i16E6SEJ1XE3RexrHSv+UKrQKUgWn1ksElBhVAhWC74=; b=0U//Am6GzCQRsB6LbKlio1U28u2HVdRaROhAv6XjrTbm04FFeh2TmuyqO8iayslyfx K5o+miG8nAh/5tiSi9F+V2APUN5iRpMUWlna1UM86gyPzw8cXcQI6Ima4e470VoLWUoz uJNr2jfk6STYoHtcuEh8ssAukSEl9P1VqoUXEPDjnJW9UONaFeLdnmqxdiE1hRmANve6 jwy8dt5/WA/y+pGHTFrNI2QH+YcptwCLXIf6P6xWBNM2geYYZTdschK4Q92UjOM9KL0/ OKhWSEf0tzS8rue9EOzRbtUflyZY8oJwCTkUL9h+xV6et/EVc1aMeWAE6qoKb16x57IU 6tFA== X-Gm-Message-State: ANoB5pnnC6uOUaQdcWVt4ID2gnRwGKIgHuHVvHJLIsLraw+nu9EnzbxJ D7T2UTB/G0FKdunB8byKfMc6wxYuKQ/Udg== X-Google-Smtp-Source: AA0mqf5yfuylOiuYjTt1prubEe1a8GxqxTj996/7IMLwczKZeOoEfPOlOooJtBe4a0OmGrUTg498bwsh10ozXg== X-Received: from dlatypov-spec.c.googlers.com ([fda3:e722:ac3:cc00:24:72f4:c0a8:3f35]) (user=dlatypov job=sendgmr) by 2002:aa7:9ad7:0:b0:56e:d7f4:3c4a with SMTP id x23-20020aa79ad7000000b0056ed7f43c4amr657937pfp.76.1667954187657; Tue, 08 Nov 2022 16:36:27 -0800 (PST) Date: Tue, 8 Nov 2022 16:36:17 -0800 In-Reply-To: <20221109003618.3784591-1-dlatypov@google.com> Mime-Version: 1.0 References: <20221109003618.3784591-1-dlatypov@google.com> X-Mailer: git-send-email 2.38.1.431.g37b22c650d-goog Message-ID: <20221109003618.3784591-2-dlatypov@google.com> Subject: [PATCH v2 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 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..8060114e3aa6 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 +we 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 Wed Nov 9 00:36:18 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Daniel Latypov X-Patchwork-Id: 13037003 X-Patchwork-Delegate: brendanhiggins@google.com 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 8BEE3C4332F for ; Wed, 9 Nov 2022 00:36:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229887AbiKIAgd (ORCPT ); Tue, 8 Nov 2022 19:36:33 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37868 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229881AbiKIAgb (ORCPT ); Tue, 8 Nov 2022 19:36:31 -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 2E34163155 for ; Tue, 8 Nov 2022 16:36:30 -0800 (PST) Received: by mail-yw1-x1149.google.com with SMTP id 00721157ae682-373582569edso149343677b3.2 for ; Tue, 08 Nov 2022 16:36:30 -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=HRpeAbE4kg4ytKwLuX0U3bbW7BL+7KJFVYe6N59c5wQ=; b=eYBlaZZdnhKMf9c7h7BMTcyzAqd2R7kggGDvkeaEUPZm9F+2bTPLZVUpkrbhMiW/Xq iXqr170uBbJzFPegUMTV9y1VU1XHGTIh6LEi51SR+K+jgTS2iNPW98vZ45iOYXD0xKro nhgpk9XnCn4/XUxICCVwyyriUpEqe4zskFFcPRGPm1ikMgO2VpQjaJkQc6E+2DL6zeV5 Cu8/6F2+YcZhvRor9YRKsYU0F45JTi52UyBq+0I5GfmEF1uLSKGiS40VrWyvKfLKBjzm BJzuEYxxTFmpYTFp3UJQUyJg1c8dkuyQ6LnKzdniqttuH3ULLUVdjBNZ7FMNjgTi40/a ejAw== 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=HRpeAbE4kg4ytKwLuX0U3bbW7BL+7KJFVYe6N59c5wQ=; b=ywkVX3w/i9ZVaFTfQl68t0wesHBPHm+WTGG2zXMGfji5qI+21UbBF4bjlG3HsVVGvo OPGBwGKpQbd9qEOlE0vbdPeHWyS/70q/KW+KvSr5rZQ7Z1mQ2m+zzWsoRC+PovXATW1W dhKVFG9RucUlCqhI5bZyKT5oT8RPEPGktXiRwUm34Ofln5tsat5Qc7fF8qxPfq09cV2O pNwPj8nnMPWZzeyDFKeNhyI6DoB7pxFsK3rzQ5rSt9gaXBpVpCydBPJ1uL48XLuvcr5O t2y3XliYA1sHf39vF0zjVZ1sJ/PwplHl98ekTTUnRt6ZjWn+5VKX2msxN4xKJr7m/bcM /65Q== X-Gm-Message-State: ACrzQf1ewBBzjBS1YFXAmaLmWNqgzW35vvjD08CClDkUs4q8Na97aHt0 +Gcr5yDFmM81PdMfRO8n2RLxodLIf679YQ== X-Google-Smtp-Source: AMsMyM4JQ/Y9XbqsO2B788tot8DOOsEFozyJAxqBv/P6ojQnZR/H16KWdNWMw4b0fhDXk3NBsyLJdKHIqXfEBA== X-Received: from dlatypov-spec.c.googlers.com ([fda3:e722:ac3:cc00:24:72f4:c0a8:3f35]) (user=dlatypov job=sendgmr) by 2002:a81:80c3:0:b0:349:8498:a05b with SMTP id q186-20020a8180c3000000b003498498a05bmr55480921ywf.403.1667954189465; Tue, 08 Nov 2022 16:36:29 -0800 (PST) Date: Tue, 8 Nov 2022 16:36:18 -0800 In-Reply-To: <20221109003618.3784591-1-dlatypov@google.com> Mime-Version: 1.0 References: <20221109003618.3784591-1-dlatypov@google.com> X-Mailer: git-send-email 2.38.1.431.g37b22c650d-goog Message-ID: <20221109003618.3784591-3-dlatypov@google.com> Subject: [PATCH v2 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 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.