A number of test features need to do pretty complicated string printing where it may not be possible to rely on a single preallocated string with parameters.

So provide a library for constructing the string as you go similar to C++'s std::string.

Signed-off-by: Brendan Higgins brendanhiggins@google.com --- include/kunit/string-stream.h | 44 ++++++++++ kunit/Makefile | 2 +- kunit/string-stream.c | 149 ++++++++++++++++++++++++++++++++++ 3 files changed, 194 insertions(+), 1 deletion(-) create mode 100644 include/kunit/string-stream.h create mode 100644 kunit/string-stream.c

diff --git a/include/kunit/string-stream.h b/include/kunit/string-stream.h new file mode 100644 index 0000000000000..933ed5740cf07 --- /dev/null +++ b/include/kunit/string-stream.h @@ -0,0 +1,44 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * C++ stream style string builder used in KUnit for building messages. + * + * Copyright (C) 2018, Google LLC. + * Author: Brendan Higgins brendanhiggins@google.com + */ + +#ifndef _KUNIT_STRING_STREAM_H +#define _KUNIT_STRING_STREAM_H + +#include <linux/types.h> +#include <linux/spinlock.h> +#include <linux/kref.h> +#include <stdarg.h> + +struct string_stream_fragment { + struct list_head node; + char *fragment; +}; + +struct string_stream { + size_t length; + struct list_head fragments; + + /* length and fragments are protected by this lock */ + spinlock_t lock; + struct kref refcount; + int (*add)(struct string_stream *this, const char *fmt, ...); + int (*vadd)(struct string_stream *this, const char *fmt, va_list args); + char *(*get_string)(struct string_stream *this); + void (*clear)(struct string_stream *this); + bool (*is_empty)(struct string_stream *this); +}; + +struct string_stream *new_string_stream(void); + +void destroy_string_stream(struct string_stream *stream); + +void string_stream_get(struct string_stream *stream); + +int string_stream_put(struct string_stream *stream); + +#endif /* _KUNIT_STRING_STREAM_H */ diff --git a/kunit/Makefile b/kunit/Makefile index dd7a0299514b7..7fc613a9b383b 100644 --- a/kunit/Makefile +++ b/kunit/Makefile @@ -1 +1 @@ -obj-$(CONFIG_KUNIT) += test.o +obj-$(CONFIG_KUNIT) += test.o string-stream.o diff --git a/kunit/string-stream.c b/kunit/string-stream.c new file mode 100644 index 0000000000000..1e7efa630cc35 --- /dev/null +++ b/kunit/string-stream.c @@ -0,0 +1,149 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * C++ stream style string builder used in KUnit for building messages. + * + * Copyright (C) 2018, Google LLC. + * Author: Brendan Higgins brendanhiggins@google.com + */ + +#include <linux/list.h> +#include <linux/slab.h> +#include <kunit/string-stream.h> + +static int string_stream_vadd(struct string_stream *this, + const char *fmt, + va_list args) +{ + struct string_stream_fragment *fragment; + int len; + va_list args_for_counting; + unsigned long flags; + + /* Make a copy because `vsnprintf` could change it */ + va_copy(args_for_counting, args); + + /* Need space for null byte. */ + len = vsnprintf(NULL, 0, fmt, args_for_counting) + 1; + + va_end(args_for_counting); + + fragment = kmalloc(sizeof(*fragment), GFP_KERNEL); + if (!fragment) + return -ENOMEM; + + fragment->fragment = kmalloc(len, GFP_KERNEL); + if (!fragment->fragment) { + kfree(fragment); + return -ENOMEM; + } + + len = vsnprintf(fragment->fragment, len, fmt, args); + spin_lock_irqsave(&this->lock, flags); + this->length += len; + list_add_tail(&fragment->node, &this->fragments); + spin_unlock_irqrestore(&this->lock, flags); + return 0; +} + +static int string_stream_add(struct string_stream *this, const char *fmt, ...) +{ + va_list args; + int result; + + va_start(args, fmt); + result = string_stream_vadd(this, fmt, args); + va_end(args); + return result; +} + +static void string_stream_clear(struct string_stream *this) +{ + struct string_stream_fragment *fragment, *fragment_safe; + unsigned long flags; + + spin_lock_irqsave(&this->lock, flags); + list_for_each_entry_safe(fragment, + fragment_safe, + &this->fragments, + node) { + list_del(&fragment->node); + kfree(fragment->fragment); + kfree(fragment); + } + this->length = 0; + spin_unlock_irqrestore(&this->lock, flags); +} + +static char *string_stream_get_string(struct string_stream *this) +{ + struct string_stream_fragment *fragment; + size_t buf_len = this->length + 1; /* +1 for null byte. */ + char *buf; + unsigned long flags; + + buf = kzalloc(buf_len, GFP_KERNEL); + if (!buf) + return NULL; + + spin_lock_irqsave(&this->lock, flags); + list_for_each_entry(fragment, &this->fragments, node) + strlcat(buf, fragment->fragment, buf_len); + spin_unlock_irqrestore(&this->lock, flags); + + return buf; +} + +static bool string_stream_is_empty(struct string_stream *this) +{ + bool is_empty; + unsigned long flags; + + spin_lock_irqsave(&this->lock, flags); + is_empty = list_empty(&this->fragments); + spin_unlock_irqrestore(&this->lock, flags); + + return is_empty; +} + +void destroy_string_stream(struct string_stream *stream) +{ + stream->clear(stream); + kfree(stream); +} + +static void string_stream_destroy(struct kref *kref) +{ + struct string_stream *stream = container_of(kref, + struct string_stream, + refcount); + destroy_string_stream(stream); +} + +struct string_stream *new_string_stream(void) +{ + struct string_stream *stream = kzalloc(sizeof(*stream), GFP_KERNEL); + + if (!stream) + return NULL; + + INIT_LIST_HEAD(&stream->fragments); + spin_lock_init(&stream->lock); + kref_init(&stream->refcount); + stream->add = string_stream_add; + stream->vadd = string_stream_vadd; + stream->get_string = string_stream_get_string; + stream->clear = string_stream_clear; + stream->is_empty = string_stream_is_empty; + return stream; +} + +void string_stream_get(struct string_stream *stream) +{ + kref_get(&stream->refcount); +} + +int string_stream_put(struct string_stream *stream) +{ + return kref_put(&stream->refcount, &string_stream_destroy); +} +

Add support for expectations, which allow properties to be specified and then verified in tests.

Signed-off-by: Brendan Higgins brendanhiggins@google.com --- include/kunit/test.h | 259 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 259 insertions(+)

diff --git a/include/kunit/test.h b/include/kunit/test.h index 68320fa2452de..d652825d7296f 100644 --- a/include/kunit/test.h +++ b/include/kunit/test.h @@ -273,4 +273,263 @@ void __printf(3, 4) test_printk(const char *level, #define test_err(test, fmt, ...) \ test_printk(KERN_ERR, test, fmt, ##__VA_ARGS__)

+static inline struct test_stream *test_expect_start(struct test *test, + const char *file, + const char *line) +{ + struct test_stream *stream = test_new_stream(test); + + stream->add(stream, "EXPECTATION FAILED at %s:%s\n\t", file, line); + + return stream; +} + +static inline void test_expect_end(struct test *test, + bool success, + struct test_stream *stream) +{ + if (!success) + test->fail(test, stream); + else + stream->clear(stream); +} + +#define TEST_EXPECT_START(test) \ + test_expect_start(test, __FILE__, __stringify(__LINE__)) + +#define TEST_EXPECT_END(test, success, stream) \ + test_expect_end(test, success, stream) + +#define TEST_EXPECT(test, success, message) do { \ + struct test_stream *__stream = TEST_EXPECT_START(test); \ + \ + __stream->add(__stream, message); \ + TEST_EXPECT_END(test, success, __stream); \ +} while (0) + +/** + * TEST_SUCCEED() - A no-op expectation. Only exists for code clarity. + * @test: The test context object. + * + * The opposite of TEST_FAIL(), it is an expectation that cannot fail. In other + * words, it does nothing and only exists for code clarity. See + * TEST_EXPECT_TRUE() for more information. + */ +#define TEST_SUCCEED(test) do {} while (0) + +/** + * TEST_FAIL() - Always causes a test to fail when evaluated. + * @test: The test context object. + * @message: an informational message to be printed when the assertion is made. + * + * The opposite of TEST_SUCCEED(), it is an expectation that always fails. In + * other words, it always results in a failed expectation, and consequently + * always causes the test case to fail when evaluated. See TEST_EXPECT_TRUE() + * for more information. + */ +#define TEST_FAIL(test, message) TEST_EXPECT(test, false, message) + +/** + * TEST_EXPECT_TRUE() - Causes a test failure when the expression is not true. + * @test: The test context object. + * @condition: an arbitrary boolean expression. The test fails when this does + * not evaluate to true. + * + * This and expectations of the form `TEST_EXPECT_*` will cause the test case to + * fail when the specified condition is not met; however, it will not prevent + * the test case from continuing to run; this is otherwise known as an + * *expectation failure*. + */ +#define TEST_EXPECT_TRUE(test, condition) \ + TEST_EXPECT(test, (condition), \ + "Expected " #condition " is true, but is false.") + +/** + * TEST_EXPECT_FALSE() - Causes a test failure when the expression is not false. + * @test: The test context object. + * @condition: an arbitrary boolean expression. The test fails when this does + * not evaluate to false. + * + * Sets an expectation that @condition evaluates to false. See + * TEST_EXPECT_TRUE() for more information. + */ +#define TEST_EXPECT_FALSE(test, condition) \ + TEST_EXPECT(test, !(condition), \ + "Expected " #condition " is false, but is true.") + +static inline void test_expect_binary(struct test *test, + long long left, const char *left_name, + long long right, const char *right_name, + bool compare_result, + const char *compare_name, + const char *file, + const char *line) +{ + struct test_stream *stream = test_expect_start(test, file, line); + + stream->add(stream, + "Expected %s %s %s, but\n", + left_name, compare_name, right_name); + stream->add(stream, "\t\t%s == %lld\n", left_name, left); + stream->add(stream, "\t\t%s == %lld", right_name, right); + + test_expect_end(test, compare_result, stream); +} + +/* + * A factory macro for defining the expectations for the basic comparisons + * defined for the built in types. + * + * Unfortunately, there is no common type that all types can be promoted to for + * which all the binary operators behave the same way as for the actual types + * (for example, there is no type that long long and unsigned long long can + * both be cast to where the comparison result is preserved for all values). So + * the best we can do is do the comparison in the original types and then coerce + * everything to long long for printing; this way, the comparison behaves + * correctly and the printed out value usually makes sense without + * interpretation, but can always be interpretted to figure out the actual + * value. + */ +#define TEST_EXPECT_BINARY(test, left, condition, right) do { \ + typeof(left) __left = (left); \ + typeof(right) __right = (right); \ + test_expect_binary(test, \ + (long long) __left, #left, \ + (long long) __right, #right, \ + __left condition __right, #condition, \ + __FILE__, __stringify(__LINE__)); \ +} while (0) + +/** + * TEST_EXPECT_EQ() - Sets an expectation that @left and @right are equal. + * @test: The test context object. + * @left: an arbitrary expression that evaluates to a primitive C type. + * @right: an arbitrary expression that evaluates to a primitive C type. + * + * Sets an expectation that the values that @left and @right evaluate to are + * equal. This is semantically equivalent to + * TEST_EXPECT_TRUE(@test, (@left) == (@right)). See TEST_EXPECT_TRUE() for more + * information. + */ +#define TEST_EXPECT_EQ(test, left, right) \ + TEST_EXPECT_BINARY(test, left, ==, right) + +/** + * TEST_EXPECT_NE() - An expectation that @left and @right are not equal. + * @test: The test context object. + * @left: an arbitrary expression that evaluates to a primitive C type. + * @right: an arbitrary expression that evaluates to a primitive C type. + * + * Sets an expectation that the values that @left and @right evaluate to are not + * equal. This is semantically equivalent to + * TEST_EXPECT_TRUE(@test, (@left) != (@right)). See TEST_EXPECT_TRUE() for more + * information. + */ +#define TEST_EXPECT_NE(test, left, right) \ + TEST_EXPECT_BINARY(test, left, !=, right) + +/** + * TEST_EXPECT_LT() - An expectation that @left is less than @right. + * @test: The test context object. + * @left: an arbitrary expression that evaluates to a primitive C type. + * @right: an arbitrary expression that evaluates to a primitive C type. + * + * Sets an expectation that the value that @left evaluates to is less than the + * value that @right evaluates to. This is semantically equivalent to + * TEST_EXPECT_TRUE(@test, (@left) < (@right)). See TEST_EXPECT_TRUE() for more + * information. + */ +#define TEST_EXPECT_LT(test, left, right) \ + TEST_EXPECT_BINARY(test, left, <, right) + +/** + * TEST_EXPECT_LE() - An expectation that @left is less than or equal to @right. + * @test: The test context object. + * @left: an arbitrary expression that evaluates to a primitive C type. + * @right: an arbitrary expression that evaluates to a primitive C type. + * + * Sets an expectation that the value that @left evaluates to is less than or + * equal to the value that @right evaluates to. Semantically this is equivalent + * to TEST_EXPECT_TRUE(@test, (@left) <= (@right)). See TEST_EXPECT_TRUE() for + * more information. + */ +#define TEST_EXPECT_LE(test, left, right) \ + TEST_EXPECT_BINARY(test, left, <=, right) + +/** + * TEST_EXPECT_GT() - An expectation that @left is greater than @right. + * @test: The test context object. + * @left: an arbitrary expression that evaluates to a primitive C type. + * @right: an arbitrary expression that evaluates to a primitive C type. + * + * Sets an expectation that the value that @left evaluates to is greater than + * the value that @right evaluates to. This is semantically equivalent to + * TEST_EXPECT_TRUE(@test, (@left) > (@right)). See TEST_EXPECT_TRUE() for more + * information. + */ +#define TEST_EXPECT_GT(test, left, right) \ + TEST_EXPECT_BINARY(test, left, >, right) + +/** + * TEST_EXPECT_GE() - Expects that @left is greater than or equal to @right. + * @test: The test context object. + * @left: an arbitrary expression that evaluates to a primitive C type. + * @right: an arbitrary expression that evaluates to a primitive C type. + * + * Sets an expectation that the value that @left evaluates to is greater than + * the value that @right evaluates to. This is semantically equivalent to + * TEST_EXPECT_TRUE(@test, (@left) >= (@right)). See TEST_EXPECT_TRUE() for more + * information. + */ +#define TEST_EXPECT_GE(test, left, right) \ + TEST_EXPECT_BINARY(test, left, >=, right) + +/** + * TEST_EXPECT_STREQ() - An expectation that strings @left and @right are equal. + * @test: The test context object. + * @left: an arbitrary expression that evaluates to a null terminated string. + * @right: an arbitrary expression that evaluates to a null terminated string. + * + * Sets an expectation that the values that @left and @right evaluate to are + * equal. This is semantically equivalent to + * TEST_EXPECT_TRUE(@test, !strcmp((@left), (@right))). See TEST_EXPECT_TRUE() + * for more information. + */ +#define TEST_EXPECT_STREQ(test, left, right) do { \ + struct test_stream *__stream = TEST_EXPECT_START(test); \ + typeof(left) __left = (left); \ + typeof(right) __right = (right); \ + \ + __stream->add(__stream, "Expected " #left " == " #right ", but\n"); \ + __stream->add(__stream, "\t\t%s == %s\n", #left, __left); \ + __stream->add(__stream, "\t\t%s == %s\n", #right, __right); \ + \ + TEST_EXPECT_END(test, !strcmp(left, right), __stream); \ +} while (0) + +/** + * TEST_EXPECT_NOT_ERR_OR_NULL() - Expects that @ptr is not null and not err. + * @test: The test context object. + * @ptr: an arbitrary pointer. + * + * Sets an expectation that the value that @ptr evaluates to is not null and not + * an errno stored in a pointer. This is semantically equivalent to + * TEST_EXPECT_TRUE(@test, !IS_ERR_OR_NULL(@ptr)). See TEST_EXPECT_TRUE() for + * more information. + */ +#define TEST_EXPECT_NOT_ERR_OR_NULL(test, ptr) do { \ + struct test_stream *__stream = TEST_EXPECT_START(test); \ + typeof(ptr) __ptr = (ptr); \ + \ + if (!__ptr) \ + __stream->add(__stream, \ + "Expected " #ptr " is not null, but is."); \ + if (IS_ERR(__ptr)) \ + __stream->add(__stream, \ + "Expected " #ptr " is not error, but is: %ld", \ + PTR_ERR(__ptr)); \ + \ + TEST_EXPECT_END(test, !IS_ERR_OR_NULL(__ptr), __stream); \ +} while (0) + #endif /* _KUNIT_TEST_H */

Add a test for string stream along with a simpler example.

Signed-off-by: Brendan Higgins brendanhiggins@google.com --- kunit/Kconfig | 12 ++++++ kunit/Makefile | 4 +- kunit/example-test.c | 88 ++++++++++++++++++++++++++++++++++++++ kunit/string-stream-test.c | 61 ++++++++++++++++++++++++++ 4 files changed, 164 insertions(+), 1 deletion(-) create mode 100644 kunit/example-test.c create mode 100644 kunit/string-stream-test.c

diff --git a/kunit/Kconfig b/kunit/Kconfig index 49b44c4f6630a..c3dc7bca83f9d 100644 --- a/kunit/Kconfig +++ b/kunit/Kconfig @@ -14,4 +14,16 @@ config KUNIT special hardware. For more information, please see Documentation/kunit/

+config KUNIT_TEST + bool "KUnit test for KUnit" + depends on KUNIT + help + Enables KUnit test to test KUnit. + +config KUNIT_EXAMPLE_TEST + bool "Example test for KUnit" + depends on KUNIT + help + Enables example KUnit test to demo features of KUnit. + endmenu diff --git a/kunit/Makefile b/kunit/Makefile index 5b4562ea7f322..b437bd546ab70 100644 --- a/kunit/Makefile +++ b/kunit/Makefile @@ -1 +1,3 @@ -obj-$(CONFIG_KUNIT) += test.o string-stream.o test-stream.o +obj-$(CONFIG_KUNIT) += test.o string-stream.o test-stream.o +obj-$(CONFIG_KUNIT_TEST) += string-stream-test.o +obj-$(CONFIG_KUNIT_EXAMPLE_TEST) += example-test.o diff --git a/kunit/example-test.c b/kunit/example-test.c new file mode 100644 index 0000000000000..e9bd2b41c5fd2 --- /dev/null +++ b/kunit/example-test.c @@ -0,0 +1,88 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Example KUnit test to show how to use KUnit. + * + * Copyright (C) 2018, Google LLC. + * Author: Brendan Higgins brendanhiggins@google.com + */ + +#include <kunit/test.h> + +/* + * This is the most fundamental element of KUnit, the test case. A test case + * makes a set EXPECTATIONs and ASSERTIONs about the behavior of some code; if + * any expectations or assertions are not met, the test fails; otherwise, the + * test passes. + * + * In KUnit, a test case is just a function with the signature + * `void (*)(struct test *)`. `struct test` is a context object that stores + * information about the current test. + */ +static void example_simple_test(struct test *test) +{ + /* + * This is an EXPECTATION; it is how KUnit tests things. When you want + * to test a piece of code, you set some expectations about what the + * code should do. KUnit then runs the test and verifies that the code's + * behavior matched what was expected. + */ + TEST_EXPECT_EQ(test, 1 + 1, 2); +} + +/* + * This is run once before each test case, see the comment on + * example_test_module for more information. + */ +static int example_test_init(struct test *test) +{ + test_info(test, "initializing"); + + return 0; +} + +/* + * Here we make a list of all the test cases we want to add to the test module + * below. + */ +static struct test_case example_test_cases[] = { + /* + * This is a helper to create a test case object from a test case + * function; its exact function is not important to understand how to + * use KUnit, just know that this is how you associate test cases with a + * test module. + */ + TEST_CASE(example_simple_test), + {}, +}; + +/* + * This defines a suite or grouping of tests. + * + * Test cases are defined as belonging to the suite by adding them to + * `test_cases`. + * + * Often it is desirable to run some function which will set up things which + * will be used by every test; this is accomplished with an `init` function + * which runs before each test case is invoked. Similarly, an `exit` function + * may be specified which runs after every test case and can be used to for + * cleanup. For clarity, running tests in a test module would behave as follows: + * + * module.init(test); + * module.test_case[0](test); + * module.exit(test); + * module.init(test); + * module.test_case[1](test); + * module.exit(test); + * ...; + */ +static struct test_module example_test_module = { + .name = "example", + .init = example_test_init, + .test_cases = example_test_cases, +}; + +/* + * This registers the above test module telling KUnit that this is a suite of + * tests that need to be run. + */ +module_test(example_test_module); diff --git a/kunit/string-stream-test.c b/kunit/string-stream-test.c new file mode 100644 index 0000000000000..07c626cbfffbf --- /dev/null +++ b/kunit/string-stream-test.c @@ -0,0 +1,61 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * KUnit test for struct string_stream. + * + * Copyright (C) 2018, Google LLC. + * Author: Brendan Higgins brendanhiggins@google.com + */ + +#include <linux/slab.h> +#include <kunit/test.h> +#include <kunit/string-stream.h> + +static void string_stream_test_get_string(struct test *test) +{ + struct string_stream *stream = new_string_stream(); + char *output; + + stream->add(stream, "Foo"); + stream->add(stream, " %s", "bar"); + + output = stream->get_string(stream); + TEST_EXPECT_STREQ(test, output, "Foo bar"); + kfree(output); + destroy_string_stream(stream); +} + +static void string_stream_test_add_and_clear(struct test *test) +{ + struct string_stream *stream = new_string_stream(); + char *output; + int i; + + for (i = 0; i < 10; i++) + stream->add(stream, "A"); + + output = stream->get_string(stream); + TEST_EXPECT_STREQ(test, output, "AAAAAAAAAA"); + TEST_EXPECT_EQ(test, stream->length, 10); + TEST_EXPECT_FALSE(test, stream->is_empty(stream)); + kfree(output); + + stream->clear(stream); + + output = stream->get_string(stream); + TEST_EXPECT_STREQ(test, output, ""); + TEST_EXPECT_TRUE(test, stream->is_empty(stream)); + destroy_string_stream(stream); +} + +static struct test_case string_stream_test_cases[] = { + TEST_CASE(string_stream_test_get_string), + TEST_CASE(string_stream_test_add_and_clear), + {} +}; + +static struct test_module string_stream_test_module = { + .name = "string-stream-test", + .test_cases = string_stream_test_cases +}; +module_test(string_stream_test_module); +

Add support for assertions which are like expectations except the test terminates if the assertion is not satisfied.

Signed-off-by: Brendan Higgins brendanhiggins@google.com --- include/kunit/test.h | 272 ++++++++++++++++++++++++++++++++++++- kunit/Makefile | 2 +- kunit/string-stream-test.c | 12 +- kunit/test-test.c | 37 +++++ kunit/test.c | 131 ++++++++++++++++-- 5 files changed, 436 insertions(+), 18 deletions(-) create mode 100644 kunit/test-test.c

diff --git a/include/kunit/test.h b/include/kunit/test.h index d652825d7296f..49a9d6e43992c 100644 --- a/include/kunit/test.h +++ b/include/kunit/test.h @@ -84,9 +84,10 @@ struct test; * @name: the name of the test case. * * A test case is a function with the signature, ``void (*)(struct test *)`` - * that makes expectations (see TEST_EXPECT_TRUE()) about code under test. Each - * test case is associated with a &struct test_module and will be run after the - * module's init function and followed by the module's exit function. + * that makes expectations and assertions (see TEST_EXPECT_TRUE() and + * TEST_ASSERT_TRUE()) about code under test. Each test case is associated with + * a &struct test_module and will be run after the module's init function and + * followed by the module's exit function. * * A test case should be static and should only be created with the TEST_CASE() * macro; additionally, every array of test cases should be terminated with an @@ -168,11 +169,14 @@ struct test { const char *name; /* Read only after initialization! */ spinlock_t lock; /* Gaurds all mutable test state. */ bool success; /* Protected by lock. */ + bool death_test; /* Protected by lock. */ struct list_head resources; /* Protected by lock. */ + void (*set_death_test)(struct test *test, bool death_test); void (*vprintk)(const struct test *test, const char *level, struct va_format *vaf); void (*fail)(struct test *test, struct test_stream *stream); + void (*abort)(struct test *test); };

int test_init_test(struct test *test, const char *name); @@ -532,4 +536,266 @@ static inline void test_expect_binary(struct test *test, TEST_EXPECT_END(test, !IS_ERR_OR_NULL(__ptr), __stream); \ } while (0)

+static inline struct test_stream *test_assert_start(struct test *test, + const char *file, + const char *line) +{ + struct test_stream *stream = test_new_stream(test); + + stream->add(stream, "ASSERTION FAILED at %s:%s\n\t", file, line); + + return stream; +} + +static inline void test_assert_end(struct test *test, + bool success, + struct test_stream *stream) +{ + if (!success) { + test->fail(test, stream); + test->abort(test); + } else { + stream->clear(stream); + } +} + +#define TEST_ASSERT_START(test) \ + test_assert_start(test, __FILE__, __stringify(__LINE__)) + +#define TEST_ASSERT_END(test, success, stream) \ + test_assert_end(test, success, stream) + +#define TEST_ASSERT(test, success, message) do { \ + struct test_stream *__stream = TEST_ASSERT_START(test); \ + \ + __stream->add(__stream, message); \ + TEST_ASSERT_END(test, success, __stream); \ +} while (0) + +#define TEST_ASSERT_FAILURE(test, message) TEST_ASSERT(test, false, message) + +/** + * TEST_ASSERT_TRUE() - Causes an assertion failure when expression is not true. + * @test: The test context object. + * @condition: an arbitrary boolean expression. The test fails and aborts when + * this does not evaluate to true. + * + * This and assertions of the form `TEST_ASSERT_*` will cause the test case to + * fail *and immediately abort* when the specified condition is not met. Unlike + * an expectation failure, it will prevent the test case from continuing to run; + * this is otherwise known as an *assertion failure*. + */ +#define TEST_ASSERT_TRUE(test, condition) \ + TEST_ASSERT(test, (condition), \ + "Asserted " #condition " is true, but is false.") + +/** + * TEST_ASSERT_FALSE() - Sets an assertion that @condition is false. + * @test: The test context object. + * @condition: an arbitrary boolean expression. + * + * Sets an assertion that the value that @condition evaluates to is false. This + * is the same as TEST_EXPECT_FALSE(), except it causes an assertion failure + * (see TEST_ASSERT_TRUE()) when the assertion is not met. + */ +#define TEST_ASSERT_FALSE(test, condition) \ + TEST_ASSERT(test, !(condition), \ + "Asserted " #condition " is false, but is true.") + +static inline void test_assert_binary(struct test *test, + long long left, const char *left_name, + long long right, const char *right_name, + bool compare_result, + const char *compare_name, + const char *file, + const char *line) +{ + struct test_stream *stream = test_assert_start(test, file, line); + + stream->add(stream, + "Asserted %s %s %s, but\n", + left_name, compare_name, right_name); + stream->add(stream, "\t\t%s == %lld\n", left_name, left); + stream->add(stream, "\t\t%s == %lld", right_name, right); + + test_assert_end(test, compare_result, stream); +} + +/* + * A factory macro for defining the expectations for the basic comparisons + * defined for the built in types. + * + * Unfortunately, there is no common type that all types can be promoted to for + * which all the binary operators behave the same way as for the actual types + * (for example, there is no type that long long and unsigned long long can + * both be cast to where the comparison result is preserved for all values). So + * the best we can do is do the comparison in the original types and then coerce + * everything to long long for printing; this way, the comparison behaves + * correctly and the printed out value usually makes sense without + * interpretation, but can always be interpretted to figure out the actual + * value. + */ +#define TEST_ASSERT_BINARY(test, left, condition, right) do { \ + typeof(left) __left = (left); \ + typeof(right) __right = (right); \ + test_assert_binary(test, \ + (long long) __left, #left, \ + (long long) __right, #right, \ + __left condition __right, #condition, \ + __FILE__, __stringify(__LINE__)); \ +} while (0) + +/** + * TEST_ASSERT_EQ() - Sets an assertion that @left and @right are equal. + * @test: The test context object. + * @left: an arbitrary expression that evaluates to a primitive C type. + * @right: an arbitrary expression that evaluates to a primitive C type. + * + * Sets an assertion that the values that @left and @right evaluate to are + * equal. This is the same as TEST_EXPECT_EQ(), except it causes an assertion + * failure (see TEST_ASSERT_TRUE()) when the assertion is not met. + */ +#define TEST_ASSERT_EQ(test, left, right) \ + TEST_ASSERT_BINARY(test, left, ==, right) + +/** + * TEST_ASSERT_NE() - An assertion that @left and @right are not equal. + * @test: The test context object. + * @left: an arbitrary expression that evaluates to a primitive C type. + * @right: an arbitrary expression that evaluates to a primitive C type. + * + * Sets an assertion that the values that @left and @right evaluate to are not + * equal. This is the same as TEST_EXPECT_NE(), except it causes an assertion + * failure (see TEST_ASSERT_TRUE()) when the assertion is not met. + */ +#define TEST_ASSERT_NE(test, left, right) \ + TEST_ASSERT_BINARY(test, left, !=, right) + +/** + * TEST_ASSERT_LT() - An assertion that @left is less than @right. + * @test: The test context object. + * @left: an arbitrary expression that evaluates to a primitive C type. + * @right: an arbitrary expression that evaluates to a primitive C type. + * + * Sets an assertion that the value that @left evaluates to is less than the + * value that @right evaluates to. This is the same as TEST_EXPECT_LT(), except + * it causes an assertion failure (see TEST_ASSERT_TRUE()) when the assertion is + * not met. + */ +#define TEST_ASSERT_LT(test, left, right) \ + TEST_ASSERT_BINARY(test, left, <, right) + +/** + * TEST_ASSERT_LE() - An assertion that @left is less than or equal to @right. + * @test: The test context object. + * @left: an arbitrary expression that evaluates to a primitive C type. + * @right: an arbitrary expression that evaluates to a primitive C type. + * + * Sets an assertion that the value that @left evaluates to is less than or + * equal to the value that @right evaluates to. This is the same as + * TEST_EXPECT_LE(), except it causes an assertion failure (see + * TEST_ASSERT_TRUE()) when the assertion is not met. + */ +#define TEST_ASSERT_LE(test, left, right) \ + TEST_ASSERT_BINARY(test, left, <=, right) + +/** + * TEST_ASSERT_GT() - An assertion that @left is greater than @right. + * @test: The test context object. + * @left: an arbitrary expression that evaluates to a primitive C type. + * @right: an arbitrary expression that evaluates to a primitive C type. + * + * Sets an assertion that the value that @left evaluates to is greater than the + * value that @right evaluates to. This is the same as TEST_EXPECT_GT(), except + * it causes an assertion failure (see TEST_ASSERT_TRUE()) when the assertion is + * not met. + */ +#define TEST_ASSERT_GT(test, left, right) \ + TEST_ASSERT_BINARY(test, left, >, right) + +/** + * TEST_ASSERT_GE() - Assertion that @left is greater than or equal to @right. + * @test: The test context object. + * @left: an arbitrary expression that evaluates to a primitive C type. + * @right: an arbitrary expression that evaluates to a primitive C type. + * + * Sets an assertion that the value that @left evaluates to is greater than the + * value that @right evaluates to. This is the same as TEST_EXPECT_GE(), except + * it causes an assertion failure (see TEST_ASSERT_TRUE()) when the assertion is + * not met. + */ +#define TEST_ASSERT_GE(test, left, right) \ + TEST_ASSERT_BINARY(test, left, >=, right) + +/** + * TEST_ASSERT_STREQ() - An assertion that strings @left and @right are equal. + * @test: The test context object. + * @left: an arbitrary expression that evaluates to a null terminated string. + * @right: an arbitrary expression that evaluates to a null terminated string. + * + * Sets an assertion that the values that @left and @right evaluate to are + * equal. This is the same as TEST_EXPECT_STREQ(), except it causes an + * assertion failure (see TEST_ASSERT_TRUE()) when the assertion is not met. + */ +#define TEST_ASSERT_STREQ(test, left, right) do { \ + struct test_stream *__stream = TEST_ASSERT_START(test); \ + typeof(left) __left = (left); \ + typeof(right) __right = (right); \ + \ + __stream->add(__stream, "Asserted " #left " == " #right ", but\n"); \ + __stream->add(__stream, "\t\t%s == %s\n", #left, __left); \ + __stream->add(__stream, "\t\t%s == %s\n", #right, __right); \ + \ + TEST_ASSERT_END(test, !strcmp(left, right), __stream); \ +} while (0) + +/** + * TEST_ASSERT_NOT_ERR_OR_NULL() - Assertion that @ptr is not null and not err. + * @test: The test context object. + * @ptr: an arbitrary pointer. + * + * Sets an assertion that the value that @ptr evaluates to is not null and not + * an errno stored in a pointer. This is the same as + * TEST_EXPECT_NOT_ERR_OR_NULL(), except it causes an assertion failure (see + * TEST_ASSERT_TRUE()) when the assertion is not met. + */ +#define TEST_ASSERT_NOT_ERR_OR_NULL(test, ptr) do { \ + struct test_stream *__stream = TEST_ASSERT_START(test); \ + typeof(ptr) __ptr = (ptr); \ + \ + if (!__ptr) \ + __stream->add(__stream, \ + "Asserted " #ptr " is not null, but is."); \ + if (IS_ERR(__ptr)) \ + __stream->add(__stream, \ + "Asserted " #ptr " is not error, but is: %ld", \ + PTR_ERR(__ptr)); \ + \ + TEST_ASSERT_END(test, !IS_ERR_OR_NULL(__ptr), __stream); \ +} while (0) + +/** + * TEST_ASSERT_SIGSEGV() - An assertion that @expr will cause a segfault. + * @test: The test context object. + * @expr: an arbitrary block of code. + * + * Sets an assertion that @expr, when evaluated, will cause a segfault. + * Currently this assertion is only really useful for testing the KUnit + * framework, as a segmentation fault in normal kernel code is always incorrect. + * However, the plan is to replace this assertion with an arbitrary death + * assertion similar to + * https://github.com/google/googletest/blob/master/googletest/docs/advanced.md... + * which will probably be massaged to make sense in the context of the kernel + * (maybe assert that a panic occurred, or that BUG() was called). + * + * NOTE: no code after this assertion will ever be executed. + */ +#define TEST_ASSERT_SIGSEGV(test, expr) do { \ + test->set_death_test(test, true); \ + expr; \ + test->set_death_test(test, false); \ + TEST_ASSERT_FAILURE(test, \ + "Asserted that " #expr " would cause death, but did not.");\ +} while (0) + #endif /* _KUNIT_TEST_H */ diff --git a/kunit/Makefile b/kunit/Makefile index b437bd546ab70..919fa6faf9940 100644 --- a/kunit/Makefile +++ b/kunit/Makefile @@ -1,3 +1,3 @@ obj-$(CONFIG_KUNIT) += test.o string-stream.o test-stream.o -obj-$(CONFIG_KUNIT_TEST) += string-stream-test.o +obj-$(CONFIG_KUNIT_TEST) += test-test.o string-stream-test.o obj-$(CONFIG_KUNIT_EXAMPLE_TEST) += example-test.o diff --git a/kunit/string-stream-test.c b/kunit/string-stream-test.c index 07c626cbfffbf..5947fada67d96 100644 --- a/kunit/string-stream-test.c +++ b/kunit/string-stream-test.c @@ -19,7 +19,7 @@ static void string_stream_test_get_string(struct test *test) stream->add(stream, " %s", "bar");

output = stream->get_string(stream); - TEST_EXPECT_STREQ(test, output, "Foo bar"); + TEST_ASSERT_STREQ(test, output, "Foo bar"); kfree(output); destroy_string_stream(stream); } @@ -34,16 +34,16 @@ static void string_stream_test_add_and_clear(struct test *test) stream->add(stream, "A");

output = stream->get_string(stream); - TEST_EXPECT_STREQ(test, output, "AAAAAAAAAA"); - TEST_EXPECT_EQ(test, stream->length, 10); - TEST_EXPECT_FALSE(test, stream->is_empty(stream)); + TEST_ASSERT_STREQ(test, output, "AAAAAAAAAA"); + TEST_ASSERT_EQ(test, stream->length, 10); + TEST_ASSERT_FALSE(test, stream->is_empty(stream)); kfree(output);

stream->clear(stream);

output = stream->get_string(stream); - TEST_EXPECT_STREQ(test, output, ""); - TEST_EXPECT_TRUE(test, stream->is_empty(stream)); + TEST_ASSERT_STREQ(test, output, ""); + TEST_ASSERT_TRUE(test, stream->is_empty(stream)); destroy_string_stream(stream); }

diff --git a/kunit/test-test.c b/kunit/test-test.c new file mode 100644 index 0000000000000..fd4b90208f0c3 --- /dev/null +++ b/kunit/test-test.c @@ -0,0 +1,37 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * KUnit test for core test infrastructure. + * + * Copyright (C) 2018, Google LLC. + * Author: Brendan Higgins brendanhiggins@google.com + */ +#include <kunit/test.h> + +static void test_test_catches_segfault(struct test *test) +{ + void (*invalid_func)(void) = (void (*)(void)) SIZE_MAX; + + TEST_ASSERT_SIGSEGV(test, invalid_func()); +} + +static int test_test_init(struct test *test) +{ + return 0; +} + +static void test_test_exit(struct test *test) +{ +} + +static struct test_case test_test_cases[] = { + TEST_CASE(test_test_catches_segfault), + {}, +}; + +static struct test_module test_test_module = { + .name = "test-test", + .init = test_test_init, + .exit = test_test_exit, + .test_cases = test_test_cases, +}; +module_test(test_test_module); diff --git a/kunit/test.c b/kunit/test.c index f798183533c8d..f89cfaaf5eb79 100644 --- a/kunit/test.c +++ b/kunit/test.c @@ -32,6 +32,27 @@ static void test_set_success(struct test *test, bool success) spin_unlock_irqrestore(&test->lock, flags); }

+static bool test_get_death_test(struct test *test) +{ + unsigned long flags; + bool death_test; + + spin_lock_irqsave(&test->lock, flags); + death_test = test->death_test; + spin_unlock_irqrestore(&test->lock, flags); + + return death_test; +} + +static void test_set_death_test(struct test *test, bool death_test) +{ + unsigned long flags; + + spin_lock_irqsave(&test->lock, flags); + test->death_test = death_test; + spin_unlock_irqrestore(&test->lock, flags); +} + static int test_vprintk_emit(const struct test *test, int level, const char *fmt, @@ -70,13 +91,34 @@ static void test_fail(struct test *test, struct test_stream *stream) stream->commit(stream); }

+static void __noreturn test_abort(struct test *test) +{ + test_set_death_test(test, true); + if (current->thread.fault_catcher && current->thread.is_running_test) + UML_LONGJMP(current->thread.fault_catcher, 1); + + /* + * Attempted to abort from a not properly initialized test context. + */ + test_err(test, + "Attempted to abort from a not properly initialized test context!"); + if (!current->thread.fault_catcher) + test_err(test, "No fault_catcher present!"); + if (!current->thread.is_running_test) + test_err(test, "is_running_test not set!"); + show_stack(NULL, NULL); + BUG(); +} + int test_init_test(struct test *test, const char *name) { spin_lock_init(&test->lock); INIT_LIST_HEAD(&test->resources); test->name = name; + test->set_death_test = test_set_death_test; test->vprintk = test_vprintk; test->fail = test_fail; + test->abort = test_abort;

return 0; } @@ -122,16 +164,89 @@ static void test_run_case_cleanup(struct test *test, }

/* - * Performs all logic to run a test case. + * Handles an unexpected crash in a test case. */ -static bool test_run_case(struct test *test, - struct test_module *module, - struct test_case *test_case) +static void test_handle_test_crash(struct test *test, + struct test_module *module, + struct test_case *test_case) { - test_set_success(test, true); + test_err(test, "%s crashed", test_case->name); + /* + * TODO(brendanhiggins@google.com): This prints the stack trace up + * through this frame, not up to the frame that caused the crash. + */ + show_stack(NULL, NULL); + + test_case_internal_cleanup(test); +}

- test_run_case_internal(test, module, test_case); - test_run_case_cleanup(test, module, test_case); +/* + * Performs all logic to run a test case. It also catches most errors that + * occurs in a test case and reports them as failures. + * + * XXX: THIS DOES NOT FOLLOW NORMAL CONTROL FLOW. READ CAREFULLY!!! + */ +static bool test_run_case_catch_errors(struct test *test, + struct test_module *module, + struct test_case *test_case) +{ + jmp_buf fault_catcher; + int faulted; + + test_set_success(test, true); + test_set_death_test(test, false); + + /* + * Tell the trap subsystem that we want to catch any segfaults that + * occur. + */ + current->thread.is_running_test = true; + current->thread.fault_catcher = &fault_catcher; + + /* + * ENTER HANDLER: If a failure occurs, we enter here. + */ + faulted = UML_SETJMP(&fault_catcher); + if (faulted == 0) { + /* + * NORMAL CASE: we have not run test_run_case_internal yet. + * + * test_run_case_internal may encounter a fatal error; if it + * does, we will jump to ENTER_HANDLER above instead of + * continuing normal control flow. + */ + test_run_case_internal(test, module, test_case); + /* + * This line may never be reached. + */ + test_run_case_cleanup(test, module, test_case); + } else if (test_get_death_test(test)) { + /* + * EXPECTED DEATH: test_run_case_internal encountered + * anticipated fatal error. Everything should be in a safe + * state. + */ + test_run_case_cleanup(test, module, test_case); + } else { + /* + * UNEXPECTED DEATH: test_run_case_internal encountered an + * unanticipated fatal error. We have no idea what the state of + * the test case is in. + */ + test_handle_test_crash(test, module, test_case); + test_set_success(test, false); + } + /* + * EXIT HANDLER: test case has been run and all possible errors have + * been handled. + */ + + /* + * Tell the trap subsystem that we no longer want to catch any + * segfaults. + */ + current->thread.fault_catcher = NULL; + current->thread.is_running_test = false;

return test_get_success(test); } @@ -148,7 +263,7 @@ int test_run_tests(struct test_module *module) return ret;

for (test_case = module->test_cases; test_case->run_case; test_case++) { - success = test_run_case(&test, module, test_case); + success = test_run_case_catch_errors(&test, module, test_case); if (!success) all_passed = false;

The KUnit wrapper script interfaces with the two modules (kunit_config.py and kunit_kernel.py) and provides a command line interface for running KUnit tests. This interface allows the caller to specify options like test timeouts. The script handles configuring, building and running the kernel and tests.

The output parser (kunit_parser.py) simply strips out all the output from the kernel that is outputted as part of it's initialization sequence. This ensures that only the output from KUnit is displayed on the screen.

A full version of the output is written to test.log, or can be seen by passing --raw_output to the wrapper script.

Signed-off-by: Felix Guo felixguoxiuping@gmail.com Signed-off-by: Brendan Higgins brendanhiggins@google.com --- tools/testing/kunit/kunit.py | 40 +++++++++++++++++++++++++++++ tools/testing/kunit/kunit_kernel.py | 3 +-- tools/testing/kunit/kunit_parser.py | 24 +++++++++++++++++ 3 files changed, 65 insertions(+), 2 deletions(-) create mode 100755 tools/testing/kunit/kunit.py create mode 100644 tools/testing/kunit/kunit_parser.py

diff --git a/tools/testing/kunit/kunit.py b/tools/testing/kunit/kunit.py new file mode 100755 index 0000000000000..1356be404996b --- /dev/null +++ b/tools/testing/kunit/kunit.py @@ -0,0 +1,40 @@ +#!/usr/bin/python3 +# SPDX-License-Identifier: GPL-2.0 + +# A thin wrapper on top of the KUnit Kernel + +import argparse +import sys +import os + +import kunit_config +import kunit_kernel +import kunit_parser + +parser = argparse.ArgumentParser(description='Runs KUnit tests.') + +parser.add_argument('--raw_output', help='don't format output from kernel', + action='store_true') + +parser.add_argument('--timeout', help='maximum number of seconds to allow for ' + 'all tests to run. This does not include time taken to ' + 'build the tests.', type=int, default=300, + metavar='timeout') + +cli_args = parser.parse_args() +linux = kunit_kernel.LinuxSourceTree() + +success = linux.build_reconfig() +if not success: + quit() + +print('Building KUnit Kernel ...') +success = linux.build_um_kernel() +if not success: + quit() + +print('Starting KUnit Kernel ...') +if cli_args.raw_output: + kunit_parser.raw_output(linux.run_kernel(timeout=cli_args.timeout)) +else: + kunit_parser.parse_run_tests(linux.run_kernel(timeout=cli_args.timeout)) diff --git a/tools/testing/kunit/kunit_kernel.py b/tools/testing/kunit/kunit_kernel.py index 87abaede50513..c1259b174f7d4 100644 --- a/tools/testing/kunit/kunit_kernel.py +++ b/tools/testing/kunit/kunit_kernel.py @@ -113,8 +113,7 @@ class LinuxSourceTree(object): return False return True

- def run_kernel(self, args=[]): - timeout = None + def run_kernel(self, args=[], timeout=None): args.extend(['mem=256M']) process = self._ops.linux_bin(args, timeout) with open('test.log', 'w') as f: diff --git a/tools/testing/kunit/kunit_parser.py b/tools/testing/kunit/kunit_parser.py new file mode 100644 index 0000000000000..1dff3adb73bd3 --- /dev/null +++ b/tools/testing/kunit/kunit_parser.py @@ -0,0 +1,24 @@ +# SPDX-License-Identifier: GPL-2.0 + +import re + +kunit_start_re = re.compile('console .* enabled') +kunit_end_re = re.compile('List of all partitions:') + +def isolate_kunit_output(kernel_output): + started = False + for line in kernel_output: + if kunit_start_re.match(line): + started = True + elif kunit_end_re.match(line): + break + elif started: + yield line + +def raw_output(kernel_output): + for line in kernel_output: + print(line) + +def parse_run_tests(kernel_output): + for output in isolate_kunit_output(kernel_output): + print(output)

Add documentation for KUnit, the Linux kernel unit testing framework. - Add intro and usage guide for KUnit - Add API reference

Signed-off-by: Felix Guo felixguoxiuping@gmail.com Signed-off-by: Brendan Higgins brendanhiggins@google.com --- Documentation/index.rst | 1 + Documentation/kunit/api/index.rst | 16 ++ Documentation/kunit/api/test.rst | 15 + Documentation/kunit/faq.rst | 46 +++ Documentation/kunit/index.rst | 80 ++++++ Documentation/kunit/start.rst | 180 ++++++++++++ Documentation/kunit/usage.rst | 447 ++++++++++++++++++++++++++++++ 7 files changed, 785 insertions(+) create mode 100644 Documentation/kunit/api/index.rst create mode 100644 Documentation/kunit/api/test.rst create mode 100644 Documentation/kunit/faq.rst create mode 100644 Documentation/kunit/index.rst create mode 100644 Documentation/kunit/start.rst create mode 100644 Documentation/kunit/usage.rst

diff --git a/Documentation/index.rst b/Documentation/index.rst index 5db7e87c7cb1d..275ef4db79f61 100644 --- a/Documentation/index.rst +++ b/Documentation/index.rst @@ -68,6 +68,7 @@ merged much easier. kernel-hacking/index trace/index maintainer/index + kunit/index

Kernel API documentation ------------------------ diff --git a/Documentation/kunit/api/index.rst b/Documentation/kunit/api/index.rst new file mode 100644 index 0000000000000..c31c530088153 --- /dev/null +++ b/Documentation/kunit/api/index.rst @@ -0,0 +1,16 @@ +.. SPDX-License-Identifier: GPL-2.0 + +============= +API Reference +============= +.. toctree:: + + test + +This section documents the KUnit kernel testing API. It is divided into 3 +sections: + +================================= ============================================== +:doc:`test` documents all of the standard testing API + excluding mocking or mocking related features. +================================= ============================================== diff --git a/Documentation/kunit/api/test.rst b/Documentation/kunit/api/test.rst new file mode 100644 index 0000000000000..7f22db32536eb --- /dev/null +++ b/Documentation/kunit/api/test.rst @@ -0,0 +1,15 @@ +.. SPDX-License-Identifier: GPL-2.0 + +======== +Test API +======== + +This file documents all of the standard testing API excluding mocking or mocking +related features. + +.. kernel-doc:: include/kunit/test.h + :internal: + +.. kernel-doc:: include/kunit/test-stream.h + :internal: + diff --git a/Documentation/kunit/faq.rst b/Documentation/kunit/faq.rst new file mode 100644 index 0000000000000..cb8e4fb2257a0 --- /dev/null +++ b/Documentation/kunit/faq.rst @@ -0,0 +1,46 @@ +.. SPDX-License-Identifier: GPL-2.0 + +========================================= +Frequently Asked Questions +========================================= + +How is this different from Autotest, kselftest, etc? +==================================================== +KUnit is a unit testing framework. Autotest, kselftest (and some others) are +not. + +A `unit test https://martinfowler.com/bliki/UnitTest.html`_ is supposed to +test a single unit of code in isolation, hence the name. A unit test should be +the finest granularity of testing and as such should allow all possible code +paths to be tested in the code under test; this is only possible if the code +under test is very small and does not have any external dependencies outside of +the test's control like hardware. + +There are no testing frameworks currently available for the kernel that do not +require installing the kernel on a test machine or in a VM and all require +tests to be written in userspace and run on the kernel under test; this is true +for Autotest, kselftest, and some others, disqualifying any of them from being +considered unit testing frameworks. + +What is the difference between a unit test and these other kinds of tests? +========================================================================== +Most existing tests for the Linux kernel would be categorized as an integration +test, or an end-to-end test. + +- A unit test is supposed to test a single unit of code in isolation, hence the + name. A unit test should be the finest granularity of testing and as such + should allow all possible code paths to be tested in the code under test; this + is only possible if the code under test is very small and does not have any + external dependencies outside of the test's control like hardware. +- An integration test tests the interaction between a minimal set of components, + usually just two or three. For example, someone might write an integration + test to test the interaction between a driver and a piece of hardware, or to + test the interaction between the userspace libraries the kernel provides and + the kernel itself; however, one of these tests would probably not test the + entire kernel along with hardware interactions and interactions with the + userspace. +- An end-to-end test usually tests the entire system from the perspective of the + code under test. For example, someone might write an end-to-end test for the + kernel by installing a production configuration of the kernel on production + hardware with a production userspace and then trying to exercise some behavior + that depends on interactions between the hardware, the kernel, and userspace. diff --git a/Documentation/kunit/index.rst b/Documentation/kunit/index.rst new file mode 100644 index 0000000000000..c6710211b647f --- /dev/null +++ b/Documentation/kunit/index.rst @@ -0,0 +1,80 @@ +.. SPDX-License-Identifier: GPL-2.0 + +========================================= +KUnit - Unit Testing for the Linux Kernel +========================================= + +.. toctree:: + :maxdepth: 2 + + start + usage + api/index + faq + +What is KUnit? +============== + +KUnit is 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. + +KUnit is heavily inspired by JUnit, Python's unittest.mock, and +Googletest/Googlemock for C++. KUnit provides facilities for defining unit test +cases, grouping related test cases into test suites, providing common +infrastructure for running tests, and much more. + +Get started now: :doc:`start` + +Why KUnit? +========== + +A unit test is supposed to test a single unit of code in isolation, hence the +name. A unit test should be the finest granularity of testing and as such should +allow all possible code paths to be tested in the code under test; this is only +possible if the code under test is very small and does not have any external +dependencies outside of the test's control like hardware. + +Outside of KUnit, there are no testing frameworks currently +available for the kernel that do not require installing the kernel on a test +machine or in a VM and all require tests to be written in userspace running on +the kernel; this is true for Autotest, and kselftest, disqualifying +any of them from being considered unit testing frameworks. + +KUnit addresses the problem of being able to run tests without needing a virtual +machine or actual hardware with User Mode Linux. User Mode Linux is a Linux +architecture, like ARM or x86; however, unlike other architectures it compiles +to a standalone program that can be run like any other program directly inside +of a host operating system; to be clear, it does not require any virtualization +support; it is just a regular program. + +KUnit is fast. Excluding build time, from invocation to completion KUnit can run +several dozen tests in only 10 to 20 seconds; this might not sound like a big +deal to some people, but having such fast and easy to run tests fundamentally +changes the way you go about testing and even writing code in the first place. +Linus himself said in his `git talk at Google +https://gist.github.com/lorn/1272686/revisions#diff-53c65572127855f1b003db4064a94573R874`_: + + "... a lot of people seem to think that performance is about doing the + same thing, just doing it faster, and that is not true. That is not what + performance is all about. If you can do something really fast, really + well, people will start using it differently." + +In this context Linus was talking about branching and merging, +but this point also applies to testing. If your tests are slow, unreliable, are +difficult to write, and require a special setup or special hardware to run, +then you wait a lot longer to write tests, and you wait a lot longer to run +tests; this means that tests are likely to break, unlikely to test a lot of +things, and are unlikely to be rerun once they pass. If your tests are really +fast, you run them all the time, every time you make a change, and every time +someone sends you some code. Why trust that someone ran all their tests +correctly on every change when you can just run them yourself in less time than +it takes to read his / her test log? + +How do I use it? +=================== + +* :doc:`start` - for new users of KUnit +* :doc:`usage` - for a more detailed explanation of KUnit features +* :doc:`api/index` - for the list of KUnit APIs used for testing + diff --git a/Documentation/kunit/start.rst b/Documentation/kunit/start.rst new file mode 100644 index 0000000000000..bdae8e7f84b04 --- /dev/null +++ b/Documentation/kunit/start.rst @@ -0,0 +1,180 @@ +.. SPDX-License-Identifier: GPL-2.0 + +=============== +Getting Started +=============== + +Installing dependencies +======================= +KUnit has the same dependencies as the Linux kernel. As long as you can build +the kernel, you can run KUnit. + +KUnit Wrapper +============= +Included with KUnit is a simple Python wrapper that helps format the output to +easily use and read KUnit output. It handles building and running the kernel, as +well as formatting the output. + +The wrapper can be run with: + +.. code-block:: bash + + ./tools/testing/kunit/kunit.py + +Creating a kunitconfig +====================== +The Python script is a thin wrapper around Kbuild as such, it needs to be +configured with a ``kunitconfig`` file. This file essentially contains the +regular Kernel config, with the specific test targets as well. + +.. code-block:: bash + + git clone -b master https://kunit.googlesource.com/kunitconfig $PATH_TO_KUNITCONFIG_REPO + cd $PATH_TO_LINUX_REPO + ln -s $PATH_TO_KUNIT_CONFIG_REPO/kunitconfig kunitconfig + +You may want to add kunitconfig to your local gitignore. + +Verifying KUnit Works +------------------------- + +To make sure that everything is set up correctly, simply invoke the Python +wrapper from your kernel repo: + +.. code-block:: bash + + ./tools/testing/kunit/kunit.py + +.. note:: + You may want to run ``make mrproper`` first. + +If everything worked correctly, you should see the following: + +.. code-block:: bash + + Generating .config ... + Building KUnit Kernel ... + Starting KUnit Kernel ... + +followed by a list of tests that are run. All of them should be passing. + +.. note:: + Because it is building a lot of sources for the first time, the ``Building + kunit kernel`` step may take a while. + +Writing your first test +========================== + +In your kernel repo let's add some code that we can test. Create a file +``drivers/misc/example.h`` with the contents: + +.. code-block:: c + + int misc_example_add(int left, int right); + +create a file ``drivers/misc/example.c``: + +.. code-block:: c + + #include <linux/errno.h> + + #include "example.h" + + int misc_example_add(int left, int right) + { + return left + right; + } + +Now add the following lines to ``drivers/misc/Kconfig``: + +.. code-block:: kconfig + + config MISC_EXAMPLE + bool "My example" + +and the following lines to ``drivers/misc/Makefile``: + +.. code-block:: make + + obj-$(CONFIG_MISC_EXAMPLE) += example.o + +Now we are ready to write the test. The test will be in +``drivers/misc/example-test.c``: + +.. code-block:: c + + #include <kunit/test.h> + #include "example.h" + + /* Define the test cases. */ + + static void misc_example_add_test_basic(struct test *test) + { + TEST_EXPECT_EQ(test, 1, misc_example_add(1, 0)); + TEST_EXPECT_EQ(test, 2, misc_example_add(1, 1)); + TEST_EXPECT_EQ(test, 0, misc_example_add(-1, 1)); + TEST_EXPECT_EQ(test, INT_MAX, misc_example_add(0, INT_MAX)); + TEST_EXPECT_EQ(test, -1, misc_example_add(INT_MAX, INT_MIN)); + } + + static void misc_example_test_failure(struct test *test) + { + TEST_FAIL(test, "This test never passes."); + } + + static struct test_case misc_example_test_cases[] = { + TEST_CASE(misc_example_add_test_basic), + TEST_CASE(misc_example_test_failure), + {}, + }; + + static struct test_module misc_example_test_module = { + .name = "misc-example", + .test_cases = misc_example_test_cases, + }; + module_test(misc_example_test_module); + +Now add the following to ``drivers/misc/Kconfig``: + +.. code-block:: kconfig + + config MISC_EXAMPLE_TEST + bool "Test for my example" + depends on MISC_EXAMPLE && KUNIT + +and the following to ``drivers/misc/Makefile``: + +.. code-block:: make + + obj-$(CONFIG_MISC_EXAMPLE_TEST) += example-test.o + +Now add it to your ``kunitconfig``: + +.. code-block:: none + + CONFIG_MISC_EXAMPLE=y + CONFIG_MISC_EXAMPLE_TEST=y + +Now you can run the test: + +.. code-block:: bash + + ./tools/testing/kunit/kunit.py + +You should see the following failure: + +.. code-block:: none + + ... + [16:08:57] [PASSED] misc-example:misc_example_add_test_basic + [16:08:57] [FAILED] misc-example:misc_example_test_failure + [16:08:57] EXPECTATION FAILED at drivers/misc/example-test.c:17 + [16:08:57] This test never passes. + ... + +Congrats! You just wrote your first KUnit test! + +Next Steps +============= +* Check out the :doc:`usage` page for a more + in-depth explanation of KUnit. diff --git a/Documentation/kunit/usage.rst b/Documentation/kunit/usage.rst new file mode 100644 index 0000000000000..491466d4d4ec3 --- /dev/null +++ b/Documentation/kunit/usage.rst @@ -0,0 +1,447 @@ +.. SPDX-License-Identifier: GPL-2.0 + +============= +Using KUnit +============= + +The purpose of this document is to describe what KUnit is, how it works, how it +is intended to be used, and all the concepts and terminology that are needed to +understand it. This guide assumes a working knowledge of the Linux kernel and +some basic knowledge of testing. + +For a high level introduction to KUnit, including setting up KUnit for your +project, see :doc:`start`. + +Organization of this document +================================= + +This document is organized into two main sections: Testing and Isolating +Behavior. The first covers what a unit test is and how to use KUnit to write +them. The second covers how to use KUnit to isolate code and make it possible +to unit test code that was otherwise un-unit-testable. + +Testing +========== + +What is KUnit? +------------------ + +"K" is short for "kernel" so "KUnit" is the "(Linux) Kernel Unit Testing +Framework." KUnit is intended first and foremost for writing unit tests; it is +general enough that it can be used to write integration tests; however, this is +a secondary goal. KUnit has no ambition of being the only testing framework for +the kernel; for example, it does not intend to be an end-to-end testing +framework. + +What is Unit Testing? +------------------------- + +A `unit test https://martinfowler.com/bliki/UnitTest.html`_ is a test that +tests code at the smallest possible scope, a *unit* of code. In the C +programming language that's a function. + +Unit tests should be written for all the publicly exposed functions in a +compilation unit; so that is all the functions that are exported in either a +*class* (defined below) or all functions which are **not** static. + +Writing Tests +------------- + +Test Cases +~~~~~~~~~~ + +The fundamental unit in KUnit is the test case. A test case is a function with +the signature ``void (*)(struct test *test)``. It calls a function to be tested +and then sets *expectations* for what should happen. For example: + +.. code-block:: c + + void example_test_success(struct test *test) + { + } + + void example_test_failure(struct test *test) + { + TEST_FAIL(test, "This test never passes."); + } + +In the above example ``example_test_success`` always passes because it does +nothing; no expectations are set, so all expectations pass. On the other hand +``example_test_failure`` always fails because it calls ``TEST_FAIL``, which is a +special expectation that logs a message and causes the test case to fail. + +Expectations +~~~~~~~~~~~~ +An *expectation* is a way to specify that you expect a piece of code to do +something in a test. An expectation is called like a function. A test is made +by setting expectations about the behavior of a piece of code under test; when +one or more of the expectations fail, the test case fails and information about +the failure is logged. For example: + +.. code-block:: c + + void add_test_basic(struct test *test) + { + TEST_EXPECT_EQ(test, 1, add(1, 0)); + TEST_EXPECT_EQ(test, 2, add(1, 1)); + } + +In the above example ``add_test_basic`` makes a number of assertions about the +behavior of a function called ``add``; the first parameter is always of type +``struct test *``, which contains information about the current test context; +the second parameter, in this case, is what the value is expected to be; the +last value is what the value actually is. If ``add`` passes all of these +expectations, the test case, ``add_test_basic`` will pass; if any one of these +expectations fail, the test case will fail. + +It is important to understand that a test case *fails* when any expectation is +violated; however, the test will continue running, potentially trying other +expectations until the test case ends or is otherwise terminated. This is as +opposed to *assertions* which are discussed later. + +To learn about more expectations supported by KUnit, see :doc:`api/test`. + +.. note:: + A single test case should be pretty short, pretty easy to understand, + focused on a single behavior. + +For example, if we wanted to properly test the add function above, we would +create additional tests cases which would each test a different property that an +add function should have like this: + +.. code-block:: c + + void add_test_basic(struct test *test) + { + TEST_EXPECT_EQ(test, 1, add(1, 0)); + TEST_EXPECT_EQ(test, 2, add(1, 1)); + } + + void add_test_negative(struct test *test) + { + TEST_EXPECT_EQ(test, 0, add(-1, 1)); + } + + void add_test_max(struct test *test) + { + TEST_EXPECT_EQ(test, INT_MAX, add(0, INT_MAX)); + TEST_EXPECT_EQ(test, -1, add(INT_MAX, INT_MIN)); + } + + void add_test_overflow(struct test *test) + { + TEST_EXPECT_EQ(test, INT_MIN, add(INT_MAX, 1)); + } + +Notice how it is immediately obvious what all the properties that we are testing +for are. + +Assertions +~~~~~~~~~~ + +KUnit also has the concept of an *assertion*. An assertion is just like an +expectation except the assertion immediately terminates the test case if it is +not satisfied. + +For example: + +.. code-block:: c + + static void mock_test_do_expect_default_return(struct test *test) + { + struct mock_test_context *ctx = test->priv; + struct mock *mock = ctx->mock; + int param0 = 5, param1 = -5; + const char *two_param_types[] = {"int", "int"}; + const void *two_params[] = {&param0, &param1}; + const void *ret; + + ret = mock->do_expect(mock, + "test_printk", test_printk, + two_param_types, two_params, + ARRAY_SIZE(two_params)); + TEST_ASSERT_NOT_ERR_OR_NULL(test, ret); + TEST_EXPECT_EQ(test, -4, *((int *) ret)); + } + +In this example, the method under test should return a pointer to a value, so +if the pointer returned by the method is null or an errno, we don't want to +bother continuing 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 have not been satisfied to complete the test. + +Modules / Test Suites +~~~~~~~~~~~~~~~~~~~~~ + +Now obviously one unit test isn't very helpful; the power comes from having +many test cases covering all of your behaviors. Consequently it is common to +have many *similar* tests; in order to reduce duplication in these closely +related tests most unit testing frameworks provide the concept of a *test +suite*, in KUnit we call it a *test module*; all it is is just a collection of +test cases for a unit of code with a set up function that gets invoked before +every test cases and then a tear down function that gets invoked after every +test case completes. + +Example: + +.. code-block:: c + + static struct test_case example_test_cases[] = { + TEST_CASE(example_test_foo), + TEST_CASE(example_test_bar), + TEST_CASE(example_test_baz), + {}, + }; + + static struct test_module example_test_module[] = { + .name = "example", + .init = example_test_init, + .exit = example_test_exit, + .test_cases = example_test_cases, + }; + module_test(example_test_module); + +In the above example the test suite, ``example_test_module``, would run the test +cases ``example_test_foo``, ``example_test_bar``, and ``example_test_baz``, each +would have ``example_test_init`` called immediately before it and would have +``example_test_exit`` called immediately after it. +``module_test(example_test_module)`` registers the test suite with the KUnit +test framework. + +.. note:: + A test case will only be run if it is associated with a test suite. + +For a more information on these types of things see the :doc:`api/test`. + +Isolating Behavior +================== + +The most important aspect of unit testing that other forms of testing do not +provide is the ability to limit the amount of code under test to a single unit. +In practice, this is only possible by being able to control what code gets run +when the unit under test calls a function and this is usually accomplished +through some sort of indirection where a function is exposed as part of an API +such that the definition of that function can be changed without affecting the +rest of the code base. In the kernel this primarily comes from two constructs, +classes, structs that contain function pointers that are provided by the +implementer, and architecture specific functions which have definitions selected +at compile time. + +Classes +------- + +Classes are not a construct that is built into the C programming language; +however, it is an easily derived concept. Accordingly, pretty much every project +that does not use a standardized object oriented library (like GNOME's GObject) +has their own slightly different way of doing object oriented programming; the +Linux kernel is no exception. + +The central concept in kernel object oriented programming is the class. In the +kernel, a *class* is a struct that contains function pointers. This creates a +contract between *implementers* and *users* since it forces them to use the +same function signature without having to call the function directly. In order +for it to truly be a class, the function pointers must specify that a pointer +to the class, known as a *class handle*, be one of the parameters; this makes +it possible for the member functions (also known as *methods*) to have access +to member variables (more commonly known as *fields*) allowing the same +implementation to have multiple *instances*. + +Typically a class can be *overridden* by *child classes* by embedding the +*parent class* in the child class. Then when a method provided by the child +class is called, the child implementation knows that the pointer passed to it is +of a parent contained within the child; because of this, the child can compute +the pointer to itself because the pointer to the parent is always a fixed offset +from the pointer to the child; this offset is the offset of the parent contained +in the child struct. For example: + +.. code-block:: c + + struct shape { + int (*area)(struct shape *this); + }; + + struct rectangle { + struct shape parent; + int length; + int width; + }; + + int rectangle_area(struct shape *this) + { + struct rectangle *self = container_of(this, struct shape, parent); + + return self->length * self->width; + }; + + void rectangle_new(struct rectangle *self, int length, int width) + { + self->parent.area = rectangle_area; + self->length = length; + self->width = width; + } + +In this example (as in most kernel code) the operation of computing the pointer +to the child from the pointer to the parent is done by ``container_of``. + +Faking Classes +~~~~~~~~~~~~~~ + +In order to unit test a piece of code that calls a method in a class, the +behavior of the method must be controllable, otherwise the test ceases to be a +unit test and becomes an integration test. + +A fake just provides an implementation of a piece of code that is different than +what runs in a production instance, but behaves identically from the standpoint +of the callers; this is usually done to replace a dependency that is hard to +deal with, or is slow. + +A good example for this might be implementing a fake EEPROM that just stores the +"contents" in an internal buffer. For example, let's assume we have a class that +represents an EEPROM: + +.. code-block:: c + + struct eeprom { + ssize_t (*read)(struct eeprom *this, size_t offset, char *buffer, size_t count); + ssize_t (*write)(struct eeprom *this, size_t offset, const char *buffer, size_t count); + }; + +And we want to test some code that buffers writes to the EEPROM: + +.. code-block:: c + + struct eeprom_buffer { + ssize_t (*write)(struct eeprom_buffer *this, const char *buffer, size_t count); + int flush(struct eeprom_buffer *this); + size_t flush_count; /* Flushes when buffer exceeds flush_count. */ + }; + + struct eeprom_buffer *new_eeprom_buffer(struct eeprom *eeprom); + void destroy_eeprom_buffer(struct eeprom *eeprom); + +We can easily test this code by *faking out* the underlying EEPROM: + +.. code-block:: c + + struct fake_eeprom { + struct eeprom parent; + char contents[FAKE_EEPROM_CONTENTS_SIZE]; + }; + + ssize_t fake_eeprom_read(struct eeprom *parent, size_t offset, char *buffer, size_t count) + { + struct fake_eeprom *this = container_of(parent, struct fake_eeprom, parent); + + count = min(count, FAKE_EEPROM_CONTENTS_SIZE - offset); + memcpy(buffer, this->contents + offset, count); + + return count; + } + + ssize_t fake_eeprom_write(struct eeprom *this, size_t offset, const char *buffer, size_t count) + { + struct fake_eeprom *this = container_of(parent, struct fake_eeprom, parent); + + count = min(count, FAKE_EEPROM_CONTENTS_SIZE - offset); + memcpy(this->contents + offset, buffer, count); + + return count; + } + + void fake_eeprom_init(struct fake_eeprom *this) + { + this->parent.read = fake_eeprom_read; + this->parent.write = fake_eeprom_write; + memset(this->contents, 0, FAKE_EEPROM_CONTENTS_SIZE); + } + +We can now use it to test ``struct eeprom_buffer``: + +.. code-block:: c + + struct eeprom_buffer_test { + struct fake_eeprom *fake_eeprom; + struct eeprom_buffer *eeprom_buffer; + }; + + static void eeprom_buffer_test_does_not_write_until_flush(struct test *test) + { + struct eeprom_buffer_test *ctx = test->priv; + struct eeprom_buffer *eeprom_buffer = ctx->eeprom_buffer; + struct fake_eeprom *fake_eeprom = ctx->fake_eeprom; + char buffer[] = {0xff}; + + eeprom_buffer->flush_count = SIZE_MAX; + + eeprom_buffer->write(eeprom_buffer, buffer, 1); + TEST_EXPECT_EQ(test, fake_eeprom->contents[0], 0); + + eeprom_buffer->write(eeprom_buffer, buffer, 1); + TEST_EXPECT_EQ(test, fake_eeprom->contents[1], 0); + + eeprom_buffer->flush(eeprom_buffer); + TEST_EXPECT_EQ(test, fake_eeprom->contents[0], 0xff); + TEST_EXPECT_EQ(test, fake_eeprom->contents[1], 0xff); + } + + static void eeprom_buffer_test_flushes_after_flush_count_met(struct test *test) + { + struct eeprom_buffer_test *ctx = test->priv; + struct eeprom_buffer *eeprom_buffer = ctx->eeprom_buffer; + struct fake_eeprom *fake_eeprom = ctx->fake_eeprom; + char buffer[] = {0xff}; + + eeprom_buffer->flush_count = 2; + + eeprom_buffer->write(eeprom_buffer, buffer, 1); + TEST_EXPECT_EQ(test, fake_eeprom->contents[0], 0); + + eeprom_buffer->write(eeprom_buffer, buffer, 1); + TEST_EXPECT_EQ(test, fake_eeprom->contents[0], 0xff); + TEST_EXPECT_EQ(test, fake_eeprom->contents[1], 0xff); + } + + static void eeprom_buffer_test_flushes_increments_of_flush_count(struct test *test) + { + struct eeprom_buffer_test *ctx = test->priv; + struct eeprom_buffer *eeprom_buffer = ctx->eeprom_buffer; + struct fake_eeprom *fake_eeprom = ctx->fake_eeprom; + char buffer[] = {0xff, 0xff}; + + eeprom_buffer->flush_count = 2; + + eeprom_buffer->write(eeprom_buffer, buffer, 1); + TEST_EXPECT_EQ(test, fake_eeprom->contents[0], 0); + + eeprom_buffer->write(eeprom_buffer, buffer, 2); + TEST_EXPECT_EQ(test, fake_eeprom->contents[0], 0xff); + TEST_EXPECT_EQ(test, fake_eeprom->contents[1], 0xff); + /* Should have only flushed the first two bytes. */ + TEST_EXPECT_EQ(test, fake_eeprom->contents[2], 0); + } + + static int eeprom_buffer_test_init(struct test *test) + { + struct eeprom_buffer_test *ctx; + + ctx = test_kzalloc(test, sizeof(*ctx), GFP_KERNEL); + ASSERT_NOT_ERR_OR_NULL(test, ctx); + + ctx->fake_eeprom = test_kzalloc(test, sizeof(*ctx->fake_eeprom), GFP_KERNEL); + ASSERT_NOT_ERR_OR_NULL(test, ctx->fake_eeprom); + + ctx->eeprom_buffer = new_eeprom_buffer(&ctx->fake_eeprom->parent); + ASSERT_NOT_ERR_OR_NULL(test, ctx->eeprom_buffer); + + test->priv = ctx; + + return 0; + } + + static void eeprom_buffer_test_exit(struct test *test) + { + struct eeprom_buffer_test *ctx = test->priv; + + destroy_eeprom_buffer(ctx->eeprom_buffer); + } +