221 lines · c
1// SPDX-License-Identifier: GPL-2.02/*3 * KUnit test for the linear_ranges helper.4 *5 * Copyright (C) 2020, ROHM Semiconductors.6 * Author: Matti Vaittinen <matti.vaittien@fi.rohmeurope.com>7 */8#include <kunit/test.h>9 10#include <linux/linear_range.h>11 12/* First things first. I deeply dislike unit-tests. I have seen all the hell13 * breaking loose when people who think the unit tests are "the silver bullet"14 * to kill bugs get to decide how a company should implement testing strategy...15 *16 * Believe me, it may get _really_ ridiculous. It is tempting to think that17 * walking through all the possible execution branches will nail down 100% of18 * bugs. This may lead to ideas about demands to get certain % of "test19 * coverage" - measured as line coverage. And that is one of the worst things20 * you can do.21 *22 * Ask people to provide line coverage and they do. I've seen clever tools23 * which generate test cases to test the existing functions - and by default24 * these tools expect code to be correct and just generate checks which are25 * passing when ran against current code-base. Run this generator and you'll get26 * tests that do not test code is correct but just verify nothing changes.27 * Problem is that testing working code is pointless. And if it is not28 * working, your test must not assume it is working. You won't catch any bugs29 * by such tests. What you can do is to generate a huge amount of tests.30 * Especially if you were are asked to proivde 100% line-coverage x_x. So what31 * does these tests - which are not finding any bugs now - do?32 *33 * They add inertia to every future development. I think it was Terry Pratchet34 * who wrote someone having same impact as thick syrup has to chronometre.35 * Excessive amount of unit-tests have this effect to development. If you do36 * actually find _any_ bug from code in such environment and try fixing it...37 * ...chances are you also need to fix the test cases. In sunny day you fix one38 * test. But I've done refactoring which resulted 500+ broken tests (which had39 * really zero value other than proving to managers that we do do "quality")...40 *41 * After this being said - there are situations where UTs can be handy. If you42 * have algorithms which take some input and should produce output - then you43 * can implement few, carefully selected simple UT-cases which test this. I've44 * previously used this for example for netlink and device-tree data parsing45 * functions. Feed some data examples to functions and verify the output is as46 * expected. I am not covering all the cases but I will see the logic should be47 * working.48 *49 * Here we also do some minor testing. I don't want to go through all branches50 * or test more or less obvious things - but I want to see the main logic is51 * working. And I definitely don't want to add 500+ test cases that break when52 * some simple fix is done x_x. So - let's only add few, well selected tests53 * which ensure as much logic is good as possible.54 */55 56/*57 * Test Range 1:58 * selectors: 2 3 4 5 659 * values (5): 10 20 30 40 5060 *61 * Test Range 2:62 * selectors: 7 8 9 1063 * values (4): 100 150 200 25064 */65 66#define RANGE1_MIN 1067#define RANGE1_MIN_SEL 268#define RANGE1_STEP 1069 70/* 2, 3, 4, 5, 6 */71static const unsigned int range1_sels[] = { RANGE1_MIN_SEL, RANGE1_MIN_SEL + 1,72 RANGE1_MIN_SEL + 2,73 RANGE1_MIN_SEL + 3,74 RANGE1_MIN_SEL + 4 };75/* 10, 20, 30, 40, 50 */76static const unsigned int range1_vals[] = { RANGE1_MIN, RANGE1_MIN +77 RANGE1_STEP,78 RANGE1_MIN + RANGE1_STEP * 2,79 RANGE1_MIN + RANGE1_STEP * 3,80 RANGE1_MIN + RANGE1_STEP * 4 };81 82#define RANGE2_MIN 10083#define RANGE2_MIN_SEL 784#define RANGE2_STEP 5085 86/* 7, 8, 9, 10 */87static const unsigned int range2_sels[] = { RANGE2_MIN_SEL, RANGE2_MIN_SEL + 1,88 RANGE2_MIN_SEL + 2,89 RANGE2_MIN_SEL + 3 };90/* 100, 150, 200, 250 */91static const unsigned int range2_vals[] = { RANGE2_MIN, RANGE2_MIN +92 RANGE2_STEP,93 RANGE2_MIN + RANGE2_STEP * 2,94 RANGE2_MIN + RANGE2_STEP * 3 };95 96#define RANGE1_NUM_VALS (ARRAY_SIZE(range1_vals))97#define RANGE2_NUM_VALS (ARRAY_SIZE(range2_vals))98#define RANGE_NUM_VALS (RANGE1_NUM_VALS + RANGE2_NUM_VALS)99 100#define RANGE1_MAX_SEL (RANGE1_MIN_SEL + RANGE1_NUM_VALS - 1)101#define RANGE1_MAX_VAL (range1_vals[RANGE1_NUM_VALS - 1])102 103#define RANGE2_MAX_SEL (RANGE2_MIN_SEL + RANGE2_NUM_VALS - 1)104#define RANGE2_MAX_VAL (range2_vals[RANGE2_NUM_VALS - 1])105 106#define SMALLEST_SEL RANGE1_MIN_SEL107#define SMALLEST_VAL RANGE1_MIN108 109static struct linear_range testr[] = {110 LINEAR_RANGE(RANGE1_MIN, RANGE1_MIN_SEL, RANGE1_MAX_SEL, RANGE1_STEP),111 LINEAR_RANGE(RANGE2_MIN, RANGE2_MIN_SEL, RANGE2_MAX_SEL, RANGE2_STEP),112};113 114static void range_test_get_value(struct kunit *test)115{116 int ret, i;117 unsigned int sel, val;118 119 for (i = 0; i < RANGE1_NUM_VALS; i++) {120 sel = range1_sels[i];121 ret = linear_range_get_value_array(&testr[0], 2, sel, &val);122 KUNIT_EXPECT_EQ(test, 0, ret);123 KUNIT_EXPECT_EQ(test, val, range1_vals[i]);124 }125 for (i = 0; i < RANGE2_NUM_VALS; i++) {126 sel = range2_sels[i];127 ret = linear_range_get_value_array(&testr[0], 2, sel, &val);128 KUNIT_EXPECT_EQ(test, 0, ret);129 KUNIT_EXPECT_EQ(test, val, range2_vals[i]);130 }131 ret = linear_range_get_value_array(&testr[0], 2, sel + 1, &val);132 KUNIT_EXPECT_NE(test, 0, ret);133}134 135static void range_test_get_selector_high(struct kunit *test)136{137 int ret, i;138 unsigned int sel;139 bool found;140 141 for (i = 0; i < RANGE1_NUM_VALS; i++) {142 ret = linear_range_get_selector_high(&testr[0], range1_vals[i],143 &sel, &found);144 KUNIT_EXPECT_EQ(test, 0, ret);145 KUNIT_EXPECT_EQ(test, sel, range1_sels[i]);146 KUNIT_EXPECT_TRUE(test, found);147 }148 149 ret = linear_range_get_selector_high(&testr[0], RANGE1_MAX_VAL + 1,150 &sel, &found);151 KUNIT_EXPECT_LE(test, ret, 0);152 153 ret = linear_range_get_selector_high(&testr[0], RANGE1_MIN - 1,154 &sel, &found);155 KUNIT_EXPECT_EQ(test, 0, ret);156 KUNIT_EXPECT_FALSE(test, found);157 KUNIT_EXPECT_EQ(test, sel, range1_sels[0]);158}159 160static void range_test_get_value_amount(struct kunit *test)161{162 int ret;163 164 ret = linear_range_values_in_range_array(&testr[0], 2);165 KUNIT_EXPECT_EQ(test, (int)RANGE_NUM_VALS, ret);166}167 168static void range_test_get_selector_low(struct kunit *test)169{170 int i, ret;171 unsigned int sel;172 bool found;173 174 for (i = 0; i < RANGE1_NUM_VALS; i++) {175 ret = linear_range_get_selector_low_array(&testr[0], 2,176 range1_vals[i], &sel,177 &found);178 KUNIT_EXPECT_EQ(test, 0, ret);179 KUNIT_EXPECT_EQ(test, sel, range1_sels[i]);180 KUNIT_EXPECT_TRUE(test, found);181 }182 for (i = 0; i < RANGE2_NUM_VALS; i++) {183 ret = linear_range_get_selector_low_array(&testr[0], 2,184 range2_vals[i], &sel,185 &found);186 KUNIT_EXPECT_EQ(test, 0, ret);187 KUNIT_EXPECT_EQ(test, sel, range2_sels[i]);188 KUNIT_EXPECT_TRUE(test, found);189 }190 191 /*192 * Seek value greater than range max => get_selector_*_low should193 * return Ok - but set found to false as value is not in range194 */195 ret = linear_range_get_selector_low_array(&testr[0], 2,196 range2_vals[RANGE2_NUM_VALS - 1] + 1,197 &sel, &found);198 199 KUNIT_EXPECT_EQ(test, 0, ret);200 KUNIT_EXPECT_EQ(test, sel, range2_sels[RANGE2_NUM_VALS - 1]);201 KUNIT_EXPECT_FALSE(test, found);202}203 204static struct kunit_case range_test_cases[] = {205 KUNIT_CASE(range_test_get_value_amount),206 KUNIT_CASE(range_test_get_selector_high),207 KUNIT_CASE(range_test_get_selector_low),208 KUNIT_CASE(range_test_get_value),209 {},210};211 212static struct kunit_suite range_test_module = {213 .name = "linear-ranges-test",214 .test_cases = range_test_cases,215};216 217kunit_test_suites(&range_test_module);218 219MODULE_DESCRIPTION("KUnit test for the linear_ranges helper");220MODULE_LICENSE("GPL");221