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| -rw-r--r-- | lib/test_linear_ranges.c | 228 |
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diff --git a/lib/test_linear_ranges.c b/lib/test_linear_ranges.c new file mode 100644 index 000000000..676e0b8ab --- /dev/null +++ b/lib/test_linear_ranges.c @@ -0,0 +1,228 @@ +// 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[] = { + { + .min = RANGE1_MIN, + .min_sel = RANGE1_MIN_SEL, + .max_sel = RANGE1_MAX_SEL, + .step = RANGE1_STEP, + }, { + .min = RANGE2_MIN, + .min_sel = RANGE2_MIN_SEL, + .max_sel = RANGE2_MAX_SEL, + .step = 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_LICENSE("GPL"); |