1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
|
// SPDX-License-Identifier: GPL-2.0
/*
* KUnit test for the linear_ranges helper.
*
* Copyright (C) 2020, ROHM Semiconductors.
* Author: Matti Vaittinen <matti.vaittien@fi.rohmeurope.com>
*/
#include <kunit/test.h>
#include <linux/linear_range.h>
/* First things first. I deeply dislike unit-tests. I have seen all the hell
* breaking loose when people who think the unit tests are "the silver bullet"
* to kill bugs get to decide how a company should implement testing strategy...
*
* Believe me, it may get _really_ ridiculous. It is tempting to think that
* walking through all the possible execution branches will nail down 100% of
* bugs. This may lead to ideas about demands to get certain % of "test
* coverage" - measured as line coverage. And that is one of the worst things
* you can do.
*
* Ask people to provide line coverage and they do. I've seen clever tools
* which generate test cases to test the existing functions - and by default
* these tools expect code to be correct and just generate checks which are
* passing when ran against current code-base. Run this generator and you'll get
* tests that do not test code is correct but just verify nothing changes.
* Problem is that testing working code is pointless. And if it is not
* working, your test must not assume it is working. You won't catch any bugs
* by such tests. What you can do is to generate a huge amount of tests.
* Especially if you were are asked to proivde 100% line-coverage x_x. So what
* does these tests - which are not finding any bugs now - do?
*
* They add inertia to every future development. I think it was Terry Pratchet
* who wrote someone having same impact as thick syrup has to chronometre.
* Excessive amount of unit-tests have this effect to development. If you do
* actually find _any_ bug from code in such environment and try fixing it...
* ...chances are you also need to fix the test cases. In sunny day you fix one
* test. But I've done refactoring which resulted 500+ broken tests (which had
* really zero value other than proving to managers that we do do "quality")...
*
* After this being said - there are situations where UTs can be handy. If you
* have algorithms which take some input and should produce output - then you
* can implement few, carefully selected simple UT-cases which test this. I've
* previously used this for example for netlink and device-tree data parsing
* functions. Feed some data examples to functions and verify the output is as
* expected. I am not covering all the cases but I will see the logic should be
* working.
*
* Here we also do some minor testing. I don't want to go through all branches
* or test more or less obvious things - but I want to see the main logic is
* working. And I definitely don't want to add 500+ test cases that break when
* some simple fix is done x_x. So - let's only add few, well selected tests
* which ensure as much logic is good as possible.
*/
/*
* Test Range 1:
* selectors: 2 3 4 5 6
* values (5): 10 20 30 40 50
*
* Test Range 2:
* selectors: 7 8 9 10
* values (4): 100 150 200 250
*/
#define RANGE1_MIN 10
#define RANGE1_MIN_SEL 2
#define RANGE1_STEP 10
/* 2, 3, 4, 5, 6 */
static const unsigned int range1_sels[] = { RANGE1_MIN_SEL, RANGE1_MIN_SEL + 1,
RANGE1_MIN_SEL + 2,
RANGE1_MIN_SEL + 3,
RANGE1_MIN_SEL + 4 };
/* 10, 20, 30, 40, 50 */
static const unsigned int range1_vals[] = { RANGE1_MIN, RANGE1_MIN +
RANGE1_STEP,
RANGE1_MIN + RANGE1_STEP * 2,
RANGE1_MIN + RANGE1_STEP * 3,
RANGE1_MIN + RANGE1_STEP * 4 };
#define RANGE2_MIN 100
#define RANGE2_MIN_SEL 7
#define RANGE2_STEP 50
/* 7, 8, 9, 10 */
static const unsigned int range2_sels[] = { RANGE2_MIN_SEL, RANGE2_MIN_SEL + 1,
RANGE2_MIN_SEL + 2,
RANGE2_MIN_SEL + 3 };
/* 100, 150, 200, 250 */
static const unsigned int range2_vals[] = { RANGE2_MIN, RANGE2_MIN +
RANGE2_STEP,
RANGE2_MIN + RANGE2_STEP * 2,
RANGE2_MIN + RANGE2_STEP * 3 };
#define RANGE1_NUM_VALS (ARRAY_SIZE(range1_vals))
#define RANGE2_NUM_VALS (ARRAY_SIZE(range2_vals))
#define RANGE_NUM_VALS (RANGE1_NUM_VALS + RANGE2_NUM_VALS)
#define RANGE1_MAX_SEL (RANGE1_MIN_SEL + RANGE1_NUM_VALS - 1)
#define RANGE1_MAX_VAL (range1_vals[RANGE1_NUM_VALS - 1])
#define RANGE2_MAX_SEL (RANGE2_MIN_SEL + RANGE2_NUM_VALS - 1)
#define RANGE2_MAX_VAL (range2_vals[RANGE2_NUM_VALS - 1])
#define SMALLEST_SEL RANGE1_MIN_SEL
#define SMALLEST_VAL RANGE1_MIN
static struct linear_range testr[] = {
LINEAR_RANGE(RANGE1_MIN, RANGE1_MIN_SEL, RANGE1_MAX_SEL, RANGE1_STEP),
LINEAR_RANGE(RANGE2_MIN, RANGE2_MIN_SEL, RANGE2_MAX_SEL, RANGE2_STEP),
};
static void range_test_get_value(struct kunit *test)
{
int ret, i;
unsigned int sel, val;
for (i = 0; i < RANGE1_NUM_VALS; i++) {
sel = range1_sels[i];
ret = linear_range_get_value_array(&testr[0], 2, sel, &val);
KUNIT_EXPECT_EQ(test, 0, ret);
KUNIT_EXPECT_EQ(test, val, range1_vals[i]);
}
for (i = 0; i < RANGE2_NUM_VALS; i++) {
sel = range2_sels[i];
ret = linear_range_get_value_array(&testr[0], 2, sel, &val);
KUNIT_EXPECT_EQ(test, 0, ret);
KUNIT_EXPECT_EQ(test, val, range2_vals[i]);
}
ret = linear_range_get_value_array(&testr[0], 2, sel + 1, &val);
KUNIT_EXPECT_NE(test, 0, ret);
}
static void range_test_get_selector_high(struct kunit *test)
{
int ret, i;
unsigned int sel;
bool found;
for (i = 0; i < RANGE1_NUM_VALS; i++) {
ret = linear_range_get_selector_high(&testr[0], range1_vals[i],
&sel, &found);
KUNIT_EXPECT_EQ(test, 0, ret);
KUNIT_EXPECT_EQ(test, sel, range1_sels[i]);
KUNIT_EXPECT_TRUE(test, found);
}
ret = linear_range_get_selector_high(&testr[0], RANGE1_MAX_VAL + 1,
&sel, &found);
KUNIT_EXPECT_LE(test, ret, 0);
ret = linear_range_get_selector_high(&testr[0], RANGE1_MIN - 1,
&sel, &found);
KUNIT_EXPECT_EQ(test, 0, ret);
KUNIT_EXPECT_FALSE(test, found);
KUNIT_EXPECT_EQ(test, sel, range1_sels[0]);
}
static void range_test_get_value_amount(struct kunit *test)
{
int ret;
ret = linear_range_values_in_range_array(&testr[0], 2);
KUNIT_EXPECT_EQ(test, (int)RANGE_NUM_VALS, ret);
}
static void range_test_get_selector_low(struct kunit *test)
{
int i, ret;
unsigned int sel;
bool found;
for (i = 0; i < RANGE1_NUM_VALS; i++) {
ret = linear_range_get_selector_low_array(&testr[0], 2,
range1_vals[i], &sel,
&found);
KUNIT_EXPECT_EQ(test, 0, ret);
KUNIT_EXPECT_EQ(test, sel, range1_sels[i]);
KUNIT_EXPECT_TRUE(test, found);
}
for (i = 0; i < RANGE2_NUM_VALS; i++) {
ret = linear_range_get_selector_low_array(&testr[0], 2,
range2_vals[i], &sel,
&found);
KUNIT_EXPECT_EQ(test, 0, ret);
KUNIT_EXPECT_EQ(test, sel, range2_sels[i]);
KUNIT_EXPECT_TRUE(test, found);
}
/*
* Seek value greater than range max => get_selector_*_low should
* return Ok - but set found to false as value is not in range
*/
ret = linear_range_get_selector_low_array(&testr[0], 2,
range2_vals[RANGE2_NUM_VALS - 1] + 1,
&sel, &found);
KUNIT_EXPECT_EQ(test, 0, ret);
KUNIT_EXPECT_EQ(test, sel, range2_sels[RANGE2_NUM_VALS - 1]);
KUNIT_EXPECT_FALSE(test, found);
}
static struct kunit_case range_test_cases[] = {
KUNIT_CASE(range_test_get_value_amount),
KUNIT_CASE(range_test_get_selector_high),
KUNIT_CASE(range_test_get_selector_low),
KUNIT_CASE(range_test_get_value),
{},
};
static struct kunit_suite range_test_module = {
.name = "linear-ranges-test",
.test_cases = range_test_cases,
};
kunit_test_suites(&range_test_module);
MODULE_DESCRIPTION("KUnit test for the linear_ranges helper");
MODULE_LICENSE("GPL");
|
