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Add a KUnit test for the linear_ranges helper. Signed-off-by: Matti Vaittinen <matti.vaittinen@fi.rohmeurope.com> Reviewed-by: Brendan Higgins <brendanhiggins@google.com> Link: https://lore.kernel.org/r/311fea741bafdcd33804d3187c1642e24275e3e5.1588944082.git.matti.vaittinen@fi.rohmeurope.com Signed-off-by: Mark Brown <broonie@kernel.org>
228 lines
7.5 KiB
C
228 lines
7.5 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* KUnit test for the linear_ranges helper.
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*
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* Copyright (C) 2020, ROHM Semiconductors.
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* Author: Matti Vaittinen <matti.vaittien@fi.rohmeurope.com>
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*/
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#include <kunit/test.h>
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#include <linux/linear_range.h>
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/* First things first. I deeply dislike unit-tests. I have seen all the hell
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* breaking loose when people who think the unit tests are "the silver bullet"
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* to kill bugs get to decide how a company should implement testing strategy...
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*
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* Believe me, it may get _really_ ridiculous. It is tempting to think that
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* walking through all the possible execution branches will nail down 100% of
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* bugs. This may lead to ideas about demands to get certain % of "test
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* coverage" - measured as line coverage. And that is one of the worst things
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* you can do.
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*
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* Ask people to provide line coverage and they do. I've seen clever tools
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* which generate test cases to test the existing functions - and by default
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* these tools expect code to be correct and just generate checks which are
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* passing when ran against current code-base. Run this generator and you'll get
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* tests that do not test code is correct but just verify nothing changes.
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* Problem is that testing working code is pointless. And if it is not
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* working, your test must not assume it is working. You won't catch any bugs
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* by such tests. What you can do is to generate a huge amount of tests.
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* Especially if you were are asked to proivde 100% line-coverage x_x. So what
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* does these tests - which are not finding any bugs now - do?
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*
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* They add inertia to every future development. I think it was Terry Pratchet
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* who wrote someone having same impact as thick syrup has to chronometre.
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* Excessive amount of unit-tests have this effect to development. If you do
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* actually find _any_ bug from code in such environment and try fixing it...
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* ...chances are you also need to fix the test cases. In sunny day you fix one
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* test. But I've done refactoring which resulted 500+ broken tests (which had
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* really zero value other than proving to managers that we do do "quality")...
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*
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* After this being said - there are situations where UTs can be handy. If you
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* have algorithms which take some input and should produce output - then you
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* can implement few, carefully selected simple UT-cases which test this. I've
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* previously used this for example for netlink and device-tree data parsing
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* functions. Feed some data examples to functions and verify the output is as
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* expected. I am not covering all the cases but I will see the logic should be
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* working.
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*
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* Here we also do some minor testing. I don't want to go through all branches
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* or test more or less obvious things - but I want to see the main logic is
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* working. And I definitely don't want to add 500+ test cases that break when
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* some simple fix is done x_x. So - let's only add few, well selected tests
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* which ensure as much logic is good as possible.
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*/
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/*
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* Test Range 1:
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* selectors: 2 3 4 5 6
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* values (5): 10 20 30 40 50
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*
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* Test Range 2:
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* selectors: 7 8 9 10
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* values (4): 100 150 200 250
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*/
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#define RANGE1_MIN 10
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#define RANGE1_MIN_SEL 2
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#define RANGE1_STEP 10
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/* 2, 3, 4, 5, 6 */
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static const unsigned int range1_sels[] = { RANGE1_MIN_SEL, RANGE1_MIN_SEL + 1,
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RANGE1_MIN_SEL + 2,
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RANGE1_MIN_SEL + 3,
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RANGE1_MIN_SEL + 4 };
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/* 10, 20, 30, 40, 50 */
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static const unsigned int range1_vals[] = { RANGE1_MIN, RANGE1_MIN +
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RANGE1_STEP,
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RANGE1_MIN + RANGE1_STEP * 2,
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RANGE1_MIN + RANGE1_STEP * 3,
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RANGE1_MIN + RANGE1_STEP * 4 };
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#define RANGE2_MIN 100
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#define RANGE2_MIN_SEL 7
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#define RANGE2_STEP 50
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/* 7, 8, 9, 10 */
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static const unsigned int range2_sels[] = { RANGE2_MIN_SEL, RANGE2_MIN_SEL + 1,
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RANGE2_MIN_SEL + 2,
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RANGE2_MIN_SEL + 3 };
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/* 100, 150, 200, 250 */
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static const unsigned int range2_vals[] = { RANGE2_MIN, RANGE2_MIN +
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RANGE2_STEP,
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RANGE2_MIN + RANGE2_STEP * 2,
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RANGE2_MIN + RANGE2_STEP * 3 };
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#define RANGE1_NUM_VALS (ARRAY_SIZE(range1_vals))
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#define RANGE2_NUM_VALS (ARRAY_SIZE(range2_vals))
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#define RANGE_NUM_VALS (RANGE1_NUM_VALS + RANGE2_NUM_VALS)
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#define RANGE1_MAX_SEL (RANGE1_MIN_SEL + RANGE1_NUM_VALS - 1)
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#define RANGE1_MAX_VAL (range1_vals[RANGE1_NUM_VALS - 1])
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#define RANGE2_MAX_SEL (RANGE2_MIN_SEL + RANGE2_NUM_VALS - 1)
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#define RANGE2_MAX_VAL (range2_vals[RANGE2_NUM_VALS - 1])
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#define SMALLEST_SEL RANGE1_MIN_SEL
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#define SMALLEST_VAL RANGE1_MIN
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static struct linear_range testr[] = {
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{
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.min = RANGE1_MIN,
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.min_sel = RANGE1_MIN_SEL,
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.max_sel = RANGE1_MAX_SEL,
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.step = RANGE1_STEP,
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}, {
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.min = RANGE2_MIN,
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.min_sel = RANGE2_MIN_SEL,
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.max_sel = RANGE2_MAX_SEL,
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.step = RANGE2_STEP
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},
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};
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static void range_test_get_value(struct kunit *test)
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{
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int ret, i;
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unsigned int sel, val;
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for (i = 0; i < RANGE1_NUM_VALS; i++) {
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sel = range1_sels[i];
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ret = linear_range_get_value_array(&testr[0], 2, sel, &val);
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KUNIT_EXPECT_EQ(test, 0, ret);
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KUNIT_EXPECT_EQ(test, val, range1_vals[i]);
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}
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for (i = 0; i < RANGE2_NUM_VALS; i++) {
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sel = range2_sels[i];
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ret = linear_range_get_value_array(&testr[0], 2, sel, &val);
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KUNIT_EXPECT_EQ(test, 0, ret);
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KUNIT_EXPECT_EQ(test, val, range2_vals[i]);
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}
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ret = linear_range_get_value_array(&testr[0], 2, sel + 1, &val);
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KUNIT_EXPECT_NE(test, 0, ret);
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}
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static void range_test_get_selector_high(struct kunit *test)
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{
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int ret, i;
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unsigned int sel;
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bool found;
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for (i = 0; i < RANGE1_NUM_VALS; i++) {
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ret = linear_range_get_selector_high(&testr[0], range1_vals[i],
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&sel, &found);
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KUNIT_EXPECT_EQ(test, 0, ret);
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KUNIT_EXPECT_EQ(test, sel, range1_sels[i]);
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KUNIT_EXPECT_TRUE(test, found);
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}
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ret = linear_range_get_selector_high(&testr[0], RANGE1_MAX_VAL + 1,
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&sel, &found);
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KUNIT_EXPECT_LE(test, ret, 0);
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ret = linear_range_get_selector_high(&testr[0], RANGE1_MIN - 1,
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&sel, &found);
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KUNIT_EXPECT_EQ(test, 0, ret);
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KUNIT_EXPECT_FALSE(test, found);
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KUNIT_EXPECT_EQ(test, sel, range1_sels[0]);
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}
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static void range_test_get_value_amount(struct kunit *test)
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{
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int ret;
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ret = linear_range_values_in_range_array(&testr[0], 2);
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KUNIT_EXPECT_EQ(test, (int)RANGE_NUM_VALS, ret);
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}
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static void range_test_get_selector_low(struct kunit *test)
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{
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int i, ret;
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unsigned int sel;
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bool found;
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for (i = 0; i < RANGE1_NUM_VALS; i++) {
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ret = linear_range_get_selector_low_array(&testr[0], 2,
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range1_vals[i], &sel,
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&found);
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KUNIT_EXPECT_EQ(test, 0, ret);
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KUNIT_EXPECT_EQ(test, sel, range1_sels[i]);
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KUNIT_EXPECT_TRUE(test, found);
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}
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for (i = 0; i < RANGE2_NUM_VALS; i++) {
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ret = linear_range_get_selector_low_array(&testr[0], 2,
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range2_vals[i], &sel,
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&found);
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KUNIT_EXPECT_EQ(test, 0, ret);
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KUNIT_EXPECT_EQ(test, sel, range2_sels[i]);
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KUNIT_EXPECT_TRUE(test, found);
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}
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/*
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* Seek value greater than range max => get_selector_*_low should
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* return Ok - but set found to false as value is not in range
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*/
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ret = linear_range_get_selector_low_array(&testr[0], 2,
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range2_vals[RANGE2_NUM_VALS - 1] + 1,
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&sel, &found);
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KUNIT_EXPECT_EQ(test, 0, ret);
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KUNIT_EXPECT_EQ(test, sel, range2_sels[RANGE2_NUM_VALS - 1]);
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KUNIT_EXPECT_FALSE(test, found);
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}
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static struct kunit_case range_test_cases[] = {
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KUNIT_CASE(range_test_get_value_amount),
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KUNIT_CASE(range_test_get_selector_high),
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KUNIT_CASE(range_test_get_selector_low),
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KUNIT_CASE(range_test_get_value),
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{},
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};
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static struct kunit_suite range_test_module = {
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.name = "linear-ranges-test",
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.test_cases = range_test_cases,
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};
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kunit_test_suites(&range_test_module);
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MODULE_LICENSE("GPL");
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