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 before all test cases in the suite.
46  * See the comment on example_test_suite for more information.
47  */
48 static int example_test_init_suite(struct kunit_suite *suite)
49 {
50 	kunit_info(suite, "initializing suite\n");
51 
52 	return 0;
53 }
54 
55 /*
56  * This test should always be skipped.
57  */
58 static void example_skip_test(struct kunit *test)
59 {
60 	/* This line should run */
61 	kunit_info(test, "You should not see a line below.");
62 
63 	/* Skip (and abort) the test */
64 	kunit_skip(test, "this test should be skipped");
65 
66 	/* This line should not execute */
67 	KUNIT_FAIL(test, "You should not see this line.");
68 }
69 
70 /*
71  * This test should always be marked skipped.
72  */
73 static void example_mark_skipped_test(struct kunit *test)
74 {
75 	/* This line should run */
76 	kunit_info(test, "You should see a line below.");
77 
78 	/* Skip (but do not abort) the test */
79 	kunit_mark_skipped(test, "this test should be skipped");
80 
81 	/* This line should run */
82 	kunit_info(test, "You should see this line.");
83 }
84 
85 /*
86  * This test shows off all the types of KUNIT_EXPECT macros.
87  */
88 static void example_all_expect_macros_test(struct kunit *test)
89 {
90 	const u32 array1[] = { 0x0F, 0xFF };
91 	const u32 array2[] = { 0x1F, 0xFF };
92 
93 	/* Boolean assertions */
94 	KUNIT_EXPECT_TRUE(test, true);
95 	KUNIT_EXPECT_FALSE(test, false);
96 
97 	/* Integer assertions */
98 	KUNIT_EXPECT_EQ(test, 1, 1); /* check == */
99 	KUNIT_EXPECT_GE(test, 1, 1); /* check >= */
100 	KUNIT_EXPECT_LE(test, 1, 1); /* check <= */
101 	KUNIT_EXPECT_NE(test, 1, 0); /* check != */
102 	KUNIT_EXPECT_GT(test, 1, 0); /* check >  */
103 	KUNIT_EXPECT_LT(test, 0, 1); /* check <  */
104 
105 	/* Pointer assertions */
106 	KUNIT_EXPECT_NOT_ERR_OR_NULL(test, test);
107 	KUNIT_EXPECT_PTR_EQ(test, NULL, NULL);
108 	KUNIT_EXPECT_PTR_NE(test, test, NULL);
109 	KUNIT_EXPECT_NULL(test, NULL);
110 	KUNIT_EXPECT_NOT_NULL(test, test);
111 
112 	/* String assertions */
113 	KUNIT_EXPECT_STREQ(test, "hi", "hi");
114 	KUNIT_EXPECT_STRNEQ(test, "hi", "bye");
115 
116 	/* Memory block assertions */
117 	KUNIT_EXPECT_MEMEQ(test, array1, array1, sizeof(array1));
118 	KUNIT_EXPECT_MEMNEQ(test, array1, array2, sizeof(array1));
119 
120 	/*
121 	 * There are also ASSERT variants of all of the above that abort test
122 	 * execution if they fail. Useful for memory allocations, etc.
123 	 */
124 	KUNIT_ASSERT_GT(test, sizeof(char), 0);
125 
126 	/*
127 	 * There are also _MSG variants of all of the above that let you include
128 	 * additional text on failure.
129 	 */
130 	KUNIT_EXPECT_GT_MSG(test, sizeof(int), 0, "Your ints are 0-bit?!");
131 	KUNIT_ASSERT_GT_MSG(test, sizeof(int), 0, "Your ints are 0-bit?!");
132 }
133 
134 /* This is a function we'll replace with static stubs. */
135 static int add_one(int i)
136 {
137 	/* This will trigger the stub if active. */
138 	KUNIT_STATIC_STUB_REDIRECT(add_one, i);
139 
140 	return i + 1;
141 }
142 
143 /* This is used as a replacement for the above function. */
144 static int subtract_one(int i)
145 {
146 	/* We don't need to trigger the stub from the replacement. */
147 
148 	return i - 1;
149 }
150 
151 /*
152  * This test shows the use of static stubs.
153  */
154 static void example_static_stub_test(struct kunit *test)
155 {
156 	/* By default, function is not stubbed. */
157 	KUNIT_EXPECT_EQ(test, add_one(1), 2);
158 
159 	/* Replace add_one() with subtract_one(). */
160 	kunit_activate_static_stub(test, add_one, subtract_one);
161 
162 	/* add_one() is now replaced. */
163 	KUNIT_EXPECT_EQ(test, add_one(1), 0);
164 
165 	/* Return add_one() to normal. */
166 	kunit_deactivate_static_stub(test, add_one);
167 	KUNIT_EXPECT_EQ(test, add_one(1), 2);
168 }
169 
170 /*
171  * Here we make a list of all the test cases we want to add to the test suite
172  * below.
173  */
174 static struct kunit_case example_test_cases[] = {
175 	/*
176 	 * This is a helper to create a test case object from a test case
177 	 * function; its exact function is not important to understand how to
178 	 * use KUnit, just know that this is how you associate test cases with a
179 	 * test suite.
180 	 */
181 	KUNIT_CASE(example_simple_test),
182 	KUNIT_CASE(example_skip_test),
183 	KUNIT_CASE(example_mark_skipped_test),
184 	KUNIT_CASE(example_all_expect_macros_test),
185 	KUNIT_CASE(example_static_stub_test),
186 	{}
187 };
188 
189 /*
190  * This defines a suite or grouping of tests.
191  *
192  * Test cases are defined as belonging to the suite by adding them to
193  * `kunit_cases`.
194  *
195  * Often it is desirable to run some function which will set up things which
196  * will be used by every test; this is accomplished with an `init` function
197  * which runs before each test case is invoked. Similarly, an `exit` function
198  * may be specified which runs after every test case and can be used to for
199  * cleanup. For clarity, running tests in a test suite would behave as follows:
200  *
201  * suite.suite_init(suite);
202  * suite.init(test);
203  * suite.test_case[0](test);
204  * suite.exit(test);
205  * suite.init(test);
206  * suite.test_case[1](test);
207  * suite.exit(test);
208  * suite.suite_exit(suite);
209  * ...;
210  */
211 static struct kunit_suite example_test_suite = {
212 	.name = "example",
213 	.init = example_test_init,
214 	.suite_init = example_test_init_suite,
215 	.test_cases = example_test_cases,
216 };
217 
218 /*
219  * This registers the above test suite telling KUnit that this is a suite of
220  * tests that need to be run.
221  */
222 kunit_test_suites(&example_test_suite);
223 
224 MODULE_LICENSE("GPL v2");
225