1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Example KUnit test to show how to use KUnit.
4  *
5  * Copyright (C) 2019, Google LLC.
6  * Author: Brendan Higgins <brendanhiggins@google.com>
7  */
8 
9 #include <kunit/test.h>
10 #include <kunit/static_stub.h>
11 
12 /*
13  * This is the most fundamental element of KUnit, the test case. A test case
14  * makes a set EXPECTATIONs and ASSERTIONs about the behavior of some code; if
15  * any expectations or assertions are not met, the test fails; otherwise, the
16  * test passes.
17  *
18  * In KUnit, a test case is just a function with the signature
19  * `void (*)(struct kunit *)`. `struct kunit` is a context object that stores
20  * information about the current test.
21  */
22 static void example_simple_test(struct kunit *test)
23 {
24 	/*
25 	 * This is an EXPECTATION; it is how KUnit tests things. When you want
26 	 * to test a piece of code, you set some expectations about what the
27 	 * code should do. KUnit then runs the test and verifies that the code's
28 	 * behavior matched what was expected.
29 	 */
30 	KUNIT_EXPECT_EQ(test, 1 + 1, 2);
31 }
32 
33 /*
34  * This is run once before each test case, see the comment on
35  * example_test_suite for more information.
36  */
37 static int example_test_init(struct kunit *test)
38 {
39 	kunit_info(test, "initializing\n");
40 
41 	return 0;
42 }
43 
44 /*
45  * This is run once after each test case, see the comment on
46  * example_test_suite for more information.
47  */
48 static void example_test_exit(struct kunit *test)
49 {
50 	kunit_info(test, "cleaning up\n");
51 }
52 
53 
54 /*
55  * This is run once before all test cases in the suite.
56  * See the comment on example_test_suite for more information.
57  */
58 static int example_test_init_suite(struct kunit_suite *suite)
59 {
60 	kunit_info(suite, "initializing suite\n");
61 
62 	return 0;
63 }
64 
65 /*
66  * This is run once after all test cases in the suite.
67  * See the comment on example_test_suite for more information.
68  */
69 static void example_test_exit_suite(struct kunit_suite *suite)
70 {
71 	kunit_info(suite, "exiting suite\n");
72 }
73 
74 
75 /*
76  * This test should always be skipped.
77  */
78 static void example_skip_test(struct kunit *test)
79 {
80 	/* This line should run */
81 	kunit_info(test, "You should not see a line below.");
82 
83 	/* Skip (and abort) the test */
84 	kunit_skip(test, "this test should be skipped");
85 
86 	/* This line should not execute */
87 	KUNIT_FAIL(test, "You should not see this line.");
88 }
89 
90 /*
91  * This test should always be marked skipped.
92  */
93 static void example_mark_skipped_test(struct kunit *test)
94 {
95 	/* This line should run */
96 	kunit_info(test, "You should see a line below.");
97 
98 	/* Skip (but do not abort) the test */
99 	kunit_mark_skipped(test, "this test should be skipped");
100 
101 	/* This line should run */
102 	kunit_info(test, "You should see this line.");
103 }
104 
105 /*
106  * This test shows off all the types of KUNIT_EXPECT macros.
107  */
108 static void example_all_expect_macros_test(struct kunit *test)
109 {
110 	const u32 array1[] = { 0x0F, 0xFF };
111 	const u32 array2[] = { 0x1F, 0xFF };
112 
113 	/* Boolean assertions */
114 	KUNIT_EXPECT_TRUE(test, true);
115 	KUNIT_EXPECT_FALSE(test, false);
116 
117 	/* Integer assertions */
118 	KUNIT_EXPECT_EQ(test, 1, 1); /* check == */
119 	KUNIT_EXPECT_GE(test, 1, 1); /* check >= */
120 	KUNIT_EXPECT_LE(test, 1, 1); /* check <= */
121 	KUNIT_EXPECT_NE(test, 1, 0); /* check != */
122 	KUNIT_EXPECT_GT(test, 1, 0); /* check >  */
123 	KUNIT_EXPECT_LT(test, 0, 1); /* check <  */
124 
125 	/* Pointer assertions */
126 	KUNIT_EXPECT_NOT_ERR_OR_NULL(test, test);
127 	KUNIT_EXPECT_PTR_EQ(test, NULL, NULL);
128 	KUNIT_EXPECT_PTR_NE(test, test, NULL);
129 	KUNIT_EXPECT_NULL(test, NULL);
130 	KUNIT_EXPECT_NOT_NULL(test, test);
131 
132 	/* String assertions */
133 	KUNIT_EXPECT_STREQ(test, "hi", "hi");
134 	KUNIT_EXPECT_STRNEQ(test, "hi", "bye");
135 
136 	/* Memory block assertions */
137 	KUNIT_EXPECT_MEMEQ(test, array1, array1, sizeof(array1));
138 	KUNIT_EXPECT_MEMNEQ(test, array1, array2, sizeof(array1));
139 
140 	/*
141 	 * There are also ASSERT variants of all of the above that abort test
142 	 * execution if they fail. Useful for memory allocations, etc.
143 	 */
144 	KUNIT_ASSERT_GT(test, sizeof(char), 0);
145 
146 	/*
147 	 * There are also _MSG variants of all of the above that let you include
148 	 * additional text on failure.
149 	 */
150 	KUNIT_EXPECT_GT_MSG(test, sizeof(int), 0, "Your ints are 0-bit?!");
151 	KUNIT_ASSERT_GT_MSG(test, sizeof(int), 0, "Your ints are 0-bit?!");
152 }
153 
154 /* This is a function we'll replace with static stubs. */
155 static int add_one(int i)
156 {
157 	/* This will trigger the stub if active. */
158 	KUNIT_STATIC_STUB_REDIRECT(add_one, i);
159 
160 	return i + 1;
161 }
162 
163 /* This is used as a replacement for the above function. */
164 static int subtract_one(int i)
165 {
166 	/* We don't need to trigger the stub from the replacement. */
167 
168 	return i - 1;
169 }
170 
171 /*
172  * This test shows the use of static stubs.
173  */
174 static void example_static_stub_test(struct kunit *test)
175 {
176 	/* By default, function is not stubbed. */
177 	KUNIT_EXPECT_EQ(test, add_one(1), 2);
178 
179 	/* Replace add_one() with subtract_one(). */
180 	kunit_activate_static_stub(test, add_one, subtract_one);
181 
182 	/* add_one() is now replaced. */
183 	KUNIT_EXPECT_EQ(test, add_one(1), 0);
184 
185 	/* Return add_one() to normal. */
186 	kunit_deactivate_static_stub(test, add_one);
187 	KUNIT_EXPECT_EQ(test, add_one(1), 2);
188 }
189 
190 static const struct example_param {
191 	int value;
192 } example_params_array[] = {
193 	{ .value = 2, },
194 	{ .value = 1, },
195 	{ .value = 0, },
196 };
197 
198 static void example_param_get_desc(const struct example_param *p, char *desc)
199 {
200 	snprintf(desc, KUNIT_PARAM_DESC_SIZE, "example value %d", p->value);
201 }
202 
203 KUNIT_ARRAY_PARAM(example, example_params_array, example_param_get_desc);
204 
205 /*
206  * This test shows the use of params.
207  */
208 static void example_params_test(struct kunit *test)
209 {
210 	const struct example_param *param = test->param_value;
211 
212 	/* By design, param pointer will not be NULL */
213 	KUNIT_ASSERT_NOT_NULL(test, param);
214 
215 	/* Test can be skipped on unsupported param values */
216 	if (!param->value)
217 		kunit_skip(test, "unsupported param value");
218 
219 	/* You can use param values for parameterized testing */
220 	KUNIT_EXPECT_EQ(test, param->value % param->value, 0);
221 }
222 
223 /*
224  * This test should always pass. Can be used to practice filtering attributes.
225  */
226 static void example_slow_test(struct kunit *test)
227 {
228 	KUNIT_EXPECT_EQ(test, 1 + 1, 2);
229 }
230 
231 /*
232  * Here we make a list of all the test cases we want to add to the test suite
233  * below.
234  */
235 static struct kunit_case example_test_cases[] = {
236 	/*
237 	 * This is a helper to create a test case object from a test case
238 	 * function; its exact function is not important to understand how to
239 	 * use KUnit, just know that this is how you associate test cases with a
240 	 * test suite.
241 	 */
242 	KUNIT_CASE(example_simple_test),
243 	KUNIT_CASE(example_skip_test),
244 	KUNIT_CASE(example_mark_skipped_test),
245 	KUNIT_CASE(example_all_expect_macros_test),
246 	KUNIT_CASE(example_static_stub_test),
247 	KUNIT_CASE_PARAM(example_params_test, example_gen_params),
248 	KUNIT_CASE_SLOW(example_slow_test),
249 	{}
250 };
251 
252 /*
253  * This defines a suite or grouping of tests.
254  *
255  * Test cases are defined as belonging to the suite by adding them to
256  * `kunit_cases`.
257  *
258  * Often it is desirable to run some function which will set up things which
259  * will be used by every test; this is accomplished with an `init` function
260  * which runs before each test case is invoked. Similarly, an `exit` function
261  * may be specified which runs after every test case and can be used to for
262  * cleanup. For clarity, running tests in a test suite would behave as follows:
263  *
264  * suite.suite_init(suite);
265  * suite.init(test);
266  * suite.test_case[0](test);
267  * suite.exit(test);
268  * suite.init(test);
269  * suite.test_case[1](test);
270  * suite.exit(test);
271  * suite.suite_exit(suite);
272  * ...;
273  */
274 static struct kunit_suite example_test_suite = {
275 	.name = "example",
276 	.init = example_test_init,
277 	.exit = example_test_exit,
278 	.suite_init = example_test_init_suite,
279 	.suite_exit = example_test_exit_suite,
280 	.test_cases = example_test_cases,
281 };
282 
283 /*
284  * This registers the above test suite telling KUnit that this is a suite of
285  * tests that need to be run.
286  */
287 kunit_test_suites(&example_test_suite);
288 
289 MODULE_LICENSE("GPL v2");
290