linux/include/kunit/test.h

/* SPDX-License-Identifier: GPL-2.0 */
/*
 * Base unit test (KUnit) API.
 *
 * Copyright (C) 2019, Google LLC.
 * Author: Brendan Higgins <brendanhiggins@google.com>
 */

#ifndef _KUNIT_TEST_H
#define _KUNIT_TEST_H

#include <linux/types.h>

struct kunit;

/**
 * struct kunit_case - represents an individual test case.
 *
 * @run_case: the function representing the actual test case.
 * @name:     the name of the test case.
 *
 * A test case is a function with the signature,
 * ``void (*)(struct kunit *)`` that makes expectations (see
 * KUNIT_EXPECT_TRUE()) about code under test. Each test case is associated
 * with a &struct kunit_suite and will be run after the suite's init
 * function and followed by the suite's exit function.
 *
 * A test case should be static and should only be created with the
 * KUNIT_CASE() macro; additionally, every array of test cases should be
 * terminated with an empty test case.
 *
 * Example:
 *
 * .. code-block:: c
 *
 *	void add_test_basic(struct kunit *test)
 *	{
 *		KUNIT_EXPECT_EQ(test, 1, add(1, 0));
 *		KUNIT_EXPECT_EQ(test, 2, add(1, 1));
 *		KUNIT_EXPECT_EQ(test, 0, add(-1, 1));
 *		KUNIT_EXPECT_EQ(test, INT_MAX, add(0, INT_MAX));
 *		KUNIT_EXPECT_EQ(test, -1, add(INT_MAX, INT_MIN));
 *	}
 *
 *	static struct kunit_case example_test_cases[] = {
 *		KUNIT_CASE(add_test_basic),
 *		{}
 *	};
 *
 */
struct kunit_case {
	void (*run_case)(struct kunit *test);
	const char *name;

	/* private: internal use only. */
	bool success;
};

/**
 * KUNIT_CASE - A helper for creating a &struct kunit_case
 *
 * @test_name: a reference to a test case function.
 *
 * Takes a symbol for a function representing a test case and creates a
 * &struct kunit_case object from it. See the documentation for
 * &struct kunit_case for an example on how to use it.
 */
#define KUNIT_CASE(test_name) { .run_case = test_name, .name = #test_name }

/**
 * struct kunit_suite - describes a related collection of &struct kunit_case
 *
 * @name:	the name of the test. Purely informational.
 * @init:	called before every test case.
 * @exit:	called after every test case.
 * @test_cases:	a null terminated array of test cases.
 *
 * A kunit_suite is a collection of related &struct kunit_case s, such that
 * @init is called before every test case and @exit is called after every
 * test case, similar to the notion of a *test fixture* or a *test class*
 * in other unit testing frameworks like JUnit or Googletest.
 *
 * Every &struct kunit_case must be associated with a kunit_suite for KUnit
 * to run it.
 */
struct kunit_suite {
	const char name[256];
	int (*init)(struct kunit *test);
	void (*exit)(struct kunit *test);
	struct kunit_case *test_cases;
};

/**
 * struct kunit - represents a running instance of a test.
 *
 * @priv: for user to store arbitrary data. Commonly used to pass data
 *	  created in the init function (see &struct kunit_suite).
 *
 * Used to store information about the current context under which the test
 * is running. Most of this data is private and should only be accessed
 * indirectly via public functions; the one exception is @priv which can be
 * used by the test writer to store arbitrary data.
 */
struct kunit {
	void *priv;

	/* private: internal use only. */
	const char *name; /* Read only after initialization! */
	/*
	 * success starts as true, and may only be set to false during a
	 * test case; thus, it is safe to update this across multiple
	 * threads using WRITE_ONCE; however, as a consequence, it may only
	 * be read after the test case finishes once all threads associated
	 * with the test case have terminated.
	 */
	bool success; /* Read only after test_case finishes! */
};

void kunit_init_test(struct kunit *test, const char *name);

int kunit_run_tests(struct kunit_suite *suite);

/**
 * kunit_test_suite() - used to register a &struct kunit_suite with KUnit.
 *
 * @suite: a statically allocated &struct kunit_suite.
 *
 * Registers @suite with the test framework. See &struct kunit_suite for
 * more information.
 *
 * NOTE: Currently KUnit tests are all run as late_initcalls; this means
 * that they cannot test anything where tests must run at a different init
 * phase. One significant restriction resulting from this is that KUnit
 * cannot reliably test anything that is initialize in the late_init phase;
 * another is that KUnit is useless to test things that need to be run in
 * an earlier init phase.
 *
 * TODO(brendanhiggins@google.com): Don't run all KUnit tests as
 * late_initcalls.  I have some future work planned to dispatch all KUnit
 * tests from the same place, and at the very least to do so after
 * everything else is definitely initialized.
 */
#define kunit_test_suite(suite)						       \
	static int kunit_suite_init##suite(void)			       \
	{								       \
		return kunit_run_tests(&suite);				       \
	}								       \
	late_initcall(kunit_suite_init##suite)

void __printf(3, 4) kunit_printk(const char *level,
				 const struct kunit *test,
				 const char *fmt, ...);

/**
 * kunit_info() - Prints an INFO level message associated with @test.
 *
 * @test: The test context object.
 * @fmt:  A printk() style format string.
 *
 * Prints an info level message associated with the test suite being run.
 * Takes a variable number of format parameters just like printk().
 */
#define kunit_info(test, fmt, ...) \
	kunit_printk(KERN_INFO, test, fmt, ##__VA_ARGS__)

/**
 * kunit_warn() - Prints a WARN level message associated with @test.
 *
 * @test: The test context object.
 * @fmt:  A printk() style format string.
 *
 * Prints a warning level message.
 */
#define kunit_warn(test, fmt, ...) \
	kunit_printk(KERN_WARNING, test, fmt, ##__VA_ARGS__)

/**
 * kunit_err() - Prints an ERROR level message associated with @test.
 *
 * @test: The test context object.
 * @fmt:  A printk() style format string.
 *
 * Prints an error level message.
 */
#define kunit_err(test, fmt, ...) \
	kunit_printk(KERN_ERR, test, fmt, ##__VA_ARGS__)

#endif /* _KUNIT_TEST_H */