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(I'm so sorry!) Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel os linux
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#include <kunit/test.h>#include <linux/polynomial.h>
struct polynomial_test_param { const struct polynomial *poly; long data; long expected; const char *name;};
/* f(x) = 5 */static const struct polynomial poly_constant = { .total_divider = 1, .terms = { {0, 5, 1, 1}, }};
/* f(x) = 2x^2 + 3x + 5 */static const struct polynomial poly_simple = { .total_divider = 1, .terms = { {2, 2, 1, 1}, {1, 3, 1, 1}, {0, 5, 1, 1}, }};
/* f(x) = -5x + 100 */static const struct polynomial poly_negative_coef = { .total_divider = 1, .terms = { {1, -5, 1, 1}, {0, 100, 1, 1}, }};
/* f(x) = (150x + 50) / 10 */static const struct polynomial poly_total_divider = { .total_divider = 10, .terms = { {1, 150, 1, 1}, {0, 50, 1, 1}, }};
/* * f(x) = x / 2 * divider=2 applied once per multiply: mult_frac(coef, data, 2) = coef*data/2 */static const struct polynomial poly_step_divider = { .total_divider = 1, .terms = { {1, 1, 2, 1}, {0, 0, 1, 1}, }};
/* * f(x) = (100/500) * x^2 = 0.2 * x^2 * Encoded as coef=100, divider=10, divider_leftover=5: * denom = 10^2 * 5 = 500 */static const struct polynomial poly_leftover = { .total_divider = 1, .terms = { {2, 100, 10, 5}, {0, 0, 1, 1}, }};
/* * f(x) = 2x^3 (single high-degree term, no constant) * Used to exercise the power loop alone. */static const struct polynomial poly_cubic = { .total_divider = 1, .terms = { {3, 2, 1, 1}, {0, 0, 1, 1}, }};
/* * f(x) = 4x + 1 with a zero-coefficient quadratic term. * The deg-2 term contributes nothing regardless of input. */static const struct polynomial poly_zero_coef = { .total_divider = 1, .terms = { {2, 0, 1, 1}, {1, 4, 1, 1}, {0, 1, 1, 1}, }};
/* * f(x) = 9 with total_divider = 0. * The implementation treats 0 as 1 via `total_divider ?: 1`, so the * result must equal the constant term unchanged. */static const struct polynomial poly_zero_total_divider = { .total_divider = 0, .terms = { {0, 9, 1, 1}, }};
static const struct polynomial_test_param test_params[] = { { .poly = &poly_constant, .data = 0, .expected = 5, .name = "Constant polynomial at x=0", }, { .poly = &poly_constant, .data = 42, .expected = 5, .name = "Constant polynomial is independent of input", }, { .poly = &poly_simple, .data = 0, .expected = 5, /* zero input collapses all power terms */ .name = "Zero input yields constant term only", }, { .poly = &poly_simple, .data = 10, .expected = 235, /* 2*100 + 3*10 + 5 */ .name = "Simple quadratic at x=10", }, { .poly = &poly_negative_coef, .data = 10, .expected = 50, /* -5*10 + 100 */ .name = "Negative coefficient at x=10", }, { .poly = &poly_negative_coef, .data = 20, .expected = 0, /* -5*20 + 100 = 0 */ .name = "Negative coefficient result is zero", }, { .poly = &poly_total_divider, .data = 3, .expected = 50, /* (150*3 + 50) / 10 = 500/10 */ .name = "total_divider scales the final sum", }, { .poly = &poly_step_divider, .data = 100, .expected = 50, /* 1*100/2 */ .name = "Per-step divider halves input", }, { .poly = &poly_leftover, .data = 30, .expected = 180, /* 100*30^2 / (10^2 * 5) = 90000/500 */ .name = "divider_leftover with quadratic term", }, /* Boundary: unit and negative-unit input */ { /* * data=1: each mult_frac(tmp, 1, divider) strips one factor of * divider from coef per degree, so coef is left-shifted right * until intermediate precision is exhausted. * 2*1 + 3*1 + 5 = 10 */ .poly = &poly_simple, .data = 1, .expected = 10, .name = "Boundary: data=1 (unit input)", }, { /* * data=-1: even degrees produce positive contributions, * odd degrees produce negative ones. * 2*(-1)^2 + 3*(-1) + 5 = 2 - 3 + 5 = 4 */ .poly = &poly_simple, .data = -1, .expected = 4, .name = "Boundary: data=-1 (negative unit input)", },
/* Boundary: negative non-trivial input */ { /* * 2*(-3)^2 + 3*(-3) + 5 = 18 - 9 + 5 = 14 * Verifies sign handling for negative data across all degrees. */ .poly = &poly_simple, .data = -3, .expected = 14, .name = "Boundary: negative data with quadratic", },
/* Boundary: total_divider = 0 is treated as 1 */ { .poly = &poly_zero_total_divider, .data = 42, .expected = 9, .name = "Boundary: total_divider=0 defaults to 1", },
/* Boundary: zero-coefficient high-degree term */ { /* * The deg-2 term has coef=0, so it contributes 0 regardless * of data. Result: 0 + 4*10 + 1 = 41 */ .poly = &poly_zero_coef, .data = 10, .expected = 41, .name = "Boundary: zero-coefficient term is inert", },
/* Boundary: single high-degree term, no constant */ { /* 2 * 5^3 = 250; also verifies the loop terminates on deg-0 */ .poly = &poly_cubic, .data = 5, .expected = 250, .name = "Boundary: single cubic term", }, { /* 2 * (-2)^3 = -16; odd power preserves sign of negative data */ .poly = &poly_cubic, .data = -2, .expected = -16, .name = "Boundary: single cubic term, negative data", },
};
static void get_desc(const struct polynomial_test_param *param, char *desc){ strscpy(desc, param->name, KUNIT_PARAM_DESC_SIZE);}
KUNIT_ARRAY_PARAM(polynomial, test_params, get_desc);
static void polynomial_calc_test(struct kunit *test){ const struct polynomial_test_param *param = test->param_value;
KUNIT_EXPECT_EQ(test, polynomial_calc(param->poly, param->data), param->expected);}
static struct kunit_case polynomial_test_cases[] = { KUNIT_CASE_PARAM(polynomial_calc_test, polynomial_gen_params), {}};
static struct kunit_suite polynomial_test_suite = { .name = "math-polynomial", .test_cases = polynomial_test_cases,};
kunit_test_suites(&polynomial_test_suite);
MODULE_DESCRIPTION("math.polynomial_calc KUnit test suite");MODULE_LICENSE("GPL");