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+.. 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
+
+TODO(dlatypov@google.com): add an example of using ``current->kunit_test`` in
+such a hook when it's not only updated for ``CONFIG_KASAN=y``.
+
+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 :doc:`usage` page for a more
+    in-depth explanation of KUnit.