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+/* 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 */
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+#
+# KUnit base configuration
+#
+
+menu "KUnit support"
+
+config KUNIT
+ bool "Enable support for unit tests (KUnit)"
+ help
+ Enables support for kernel unit tests (KUnit), a lightweight unit
+ testing and mocking framework for the Linux kernel. These tests are
+ able to be run locally on a developer's workstation without a VM or
+ special hardware when using UML. Can also be used on most other
+ architectures. For more information, please see
+ Documentation/dev-tools/kunit/.
+
+endmenu
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+obj-$(CONFIG_KUNIT) += test.o
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+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Base unit test (KUnit) API.
+ *
+ * Copyright (C) 2019, Google LLC.
+ * Author: Brendan Higgins <brendanhiggins@google.com>
+ */
+
+#include <kunit/test.h>
+#include <linux/kernel.h>
+
+static void kunit_set_failure(struct kunit *test)
+{
+ WRITE_ONCE(test->success, false);
+}
+
+static int kunit_vprintk_emit(int level, const char *fmt, va_list args)
+{
+ return vprintk_emit(0, level, NULL, 0, fmt, args);
+}
+
+static int kunit_printk_emit(int level, const char *fmt, ...)
+{
+ va_list args;
+ int ret;
+
+ va_start(args, fmt);
+ ret = kunit_vprintk_emit(level, fmt, args);
+ va_end(args);
+
+ return ret;
+}
+
+static void kunit_vprintk(const struct kunit *test,
+ const char *level,
+ struct va_format *vaf)
+{
+ kunit_printk_emit(level[1] - '0', "\t# %s: %pV", test->name, vaf);
+}
+
+static void kunit_print_tap_version(void)
+{
+ static bool kunit_has_printed_tap_version;
+
+ if (!kunit_has_printed_tap_version) {
+ kunit_printk_emit(LOGLEVEL_INFO, "TAP version 14\n");
+ kunit_has_printed_tap_version = true;
+ }
+}
+
+static size_t kunit_test_cases_len(struct kunit_case *test_cases)
+{
+ struct kunit_case *test_case;
+ size_t len = 0;
+
+ for (test_case = test_cases; test_case->run_case; test_case++)
+ len++;
+
+ return len;
+}
+
+static void kunit_print_subtest_start(struct kunit_suite *suite)
+{
+ kunit_print_tap_version();
+ kunit_printk_emit(LOGLEVEL_INFO, "\t# Subtest: %s\n", suite->name);
+ kunit_printk_emit(LOGLEVEL_INFO,
+ "\t1..%zd\n",
+ kunit_test_cases_len(suite->test_cases));
+}
+
+static void kunit_print_ok_not_ok(bool should_indent,
+ bool is_ok,
+ size_t test_number,
+ const char *description)
+{
+ const char *indent, *ok_not_ok;
+
+ if (should_indent)
+ indent = "\t";
+ else
+ indent = "";
+
+ if (is_ok)
+ ok_not_ok = "ok";
+ else
+ ok_not_ok = "not ok";
+
+ kunit_printk_emit(LOGLEVEL_INFO,
+ "%s%s %zd - %s\n",
+ indent, ok_not_ok, test_number, description);
+}
+
+static bool kunit_suite_has_succeeded(struct kunit_suite *suite)
+{
+ const struct kunit_case *test_case;
+
+ for (test_case = suite->test_cases; test_case->run_case; test_case++)
+ if (!test_case->success)
+ return false;
+
+ return true;
+}
+
+static void kunit_print_subtest_end(struct kunit_suite *suite)
+{
+ static size_t kunit_suite_counter = 1;
+
+ kunit_print_ok_not_ok(false,
+ kunit_suite_has_succeeded(suite),
+ kunit_suite_counter++,
+ suite->name);
+}
+
+static void kunit_print_test_case_ok_not_ok(struct kunit_case *test_case,
+ size_t test_number)
+{
+ kunit_print_ok_not_ok(true,
+ test_case->success,
+ test_number,
+ test_case->name);
+}
+
+void kunit_init_test(struct kunit *test, const char *name)
+{
+ test->name = name;
+ test->success = true;
+}
+
+/*
+ * Performs all logic to run a test case.
+ */
+static void kunit_run_case(struct kunit_suite *suite,
+ struct kunit_case *test_case)
+{
+ struct kunit test;
+
+ kunit_init_test(&test, test_case->name);
+
+ if (suite->init) {
+ int ret;
+
+ ret = suite->init(&test);
+ if (ret) {
+ kunit_err(&test, "failed to initialize: %d\n", ret);
+ kunit_set_failure(&test);
+ test_case->success = test.success;
+ return;
+ }
+ }
+
+ test_case->run_case(&test);
+
+ if (suite->exit)
+ suite->exit(&test);
+
+ test_case->success = test.success;
+}
+
+int kunit_run_tests(struct kunit_suite *suite)
+{
+ struct kunit_case *test_case;
+ size_t test_case_count = 1;
+
+ kunit_print_subtest_start(suite);
+
+ for (test_case = suite->test_cases; test_case->run_case; test_case++) {
+ kunit_run_case(suite, test_case);
+ kunit_print_test_case_ok_not_ok(test_case, test_case_count++);
+ }
+
+ kunit_print_subtest_end(suite);
+
+ return 0;
+}
+
+void kunit_printk(const char *level,
+ const struct kunit *test,
+ const char *fmt, ...)
+{
+ struct va_format vaf;
+ va_list args;
+
+ va_start(args, fmt);
+
+ vaf.fmt = fmt;
+ vaf.va = &args;
+
+ kunit_vprintk(test, level, &vaf);
+
+ va_end(args);
+}