lib/math/rational: add Kunit test cases

Adds a number of test cases that cover a range of possible code paths.

[akpm@linux-foundation.org: remove non-ascii characters, fix whitespace]
[colin.king@canonical.com: fix spelling mistake "demominator" -> "denominator"]
Link: https://lkml.kernel.org/r/20210526085049.6393-1-colin.king@canonical.com
Link: https://lkml.kernel.org/r/20210525144250.214670-2-tpiepho@gmail.com
Signed-off-by: Trent Piepho <tpiepho@gmail.com>
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Daniel Latypov <dlatypov@google.com>
Cc: Oskar Schirmer <oskar@scara.com>
Cc: Yiyuan Guo <yguoaz@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index deca67d..ea9a409 100644 (file)
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -2444,6 +2444,18 @@ config SLUB_KUNIT_TEST
 
          If unsure, say N.
 
+config RATIONAL_KUNIT_TEST
+       tristate "KUnit test for rational.c" if !KUNIT_ALL_TESTS
+       depends on KUNIT
+       select RATIONAL
+       default KUNIT_ALL_TESTS
+       help
+         This builds the rational math unit test.
+         For more information on KUnit and unit tests in general please refer
+         to the KUnit documentation in Documentation/dev-tools/kunit/.
+
+         If unsure, say N.
+
 config TEST_UDELAY
        tristate "udelay test driver"
        help

diff --git a/lib/math/Makefile b/lib/math/Makefile
index 7456edb..bfac26d 100644 (file)
--- a/lib/math/Makefile
+++ b/lib/math/Makefile
@@ -6,3 +6,4 @@ obj-$(CONFIG_PRIME_NUMBERS)     += prime_numbers.o
 obj-$(CONFIG_RATIONAL)         += rational.o
 
 obj-$(CONFIG_TEST_DIV64)       += test_div64.o
+obj-$(CONFIG_RATIONAL_KUNIT_TEST) += rational-test.o

diff --git a/lib/math/rational-test.c b/lib/math/rational-test.c
new file mode 100644 (file)
index 0000000..01611dd
--- /dev/null
+++ b/lib/math/rational-test.c
@@ -0,0 +1,56 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <kunit/test.h>
+
+#include <linux/rational.h>
+
+struct rational_test_param {
+       unsigned long num, den;
+       unsigned long max_num, max_den;
+       unsigned long exp_num, exp_den;
+
+       const char *name;
+};
+
+static const struct rational_test_param test_parameters[] = {
+       { 1230, 10,     100, 20,        100, 1,    "Exceeds bounds, semi-convergent term > 1/2 last term" },
+       { 34567,100,    120, 20,        120, 1,    "Exceeds bounds, semi-convergent term < 1/2 last term" },
+       { 1, 30,        100, 10,        0, 1,      "Closest to zero" },
+       { 1, 19,        100, 10,        1, 10,     "Closest to smallest non-zero" },
+       { 27,32,        16, 16,         11, 13,    "Use convergent" },
+       { 1155, 7735,   255, 255,       33, 221,   "Exact answer" },
+       { 87, 32,       70, 32,         68, 25,    "Semiconvergent, numerator limit" },
+       { 14533, 4626,  15000, 2400,    7433, 2366, "Semiconvergent, denominator limit" },
+};
+
+static void get_desc(const struct rational_test_param *param, char *desc)
+{
+       strscpy(desc, param->name, KUNIT_PARAM_DESC_SIZE);
+}
+
+/* Creates function rational_gen_params */
+KUNIT_ARRAY_PARAM(rational, test_parameters, get_desc);
+
+static void rational_test(struct kunit *test)
+{
+       const struct rational_test_param *param = (const struct rational_test_param *)test->param_value;
+       unsigned long n = 0, d = 0;
+
+       rational_best_approximation(param->num, param->den, param->max_num, param->max_den, &n, &d);
+       KUNIT_EXPECT_EQ(test, n, param->exp_num);
+       KUNIT_EXPECT_EQ(test, d, param->exp_den);
+}
+
+static struct kunit_case rational_test_cases[] = {
+       KUNIT_CASE_PARAM(rational_test, rational_gen_params),
+       {}
+};
+
+static struct kunit_suite rational_test_suite = {
+       .name = "rational",
+       .test_cases = rational_test_cases,
+};
+
+kunit_test_suites(&rational_test_suite);
+
+MODULE_LICENSE("GPL v2");