[PATCH v3 2/2] lib/math/rational: Add Kunit test cases

From: Trent Piepho
Date: Tue May 25 2021 - 19:36:04 EST


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

Signed-off-by: Trent Piepho <tpiepho@xxxxxxxxx>
---
Changes from v2:
Rename file to follow new kunit naming convention
Fix whitespace issues
Remove unicode characters
Add more testcases

lib/Kconfig.debug | 12 ++++++++
lib/math/Makefile | 1 +
lib/math/rational_kunit.c | 60 +++++++++++++++++++++++++++++++++++++++
3 files changed, 73 insertions(+)
create mode 100644 lib/math/rational_kunit.c

diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 678c13967580..6c0e66a7d416 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -2429,6 +2429,18 @@ config BITS_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 7456edb864fc..de7d16ca3cf5 100644
--- 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_kunit.o
diff --git a/lib/math/rational_kunit.c b/lib/math/rational_kunit.c
new file mode 100644
index 000000000000..439b06fdfe66
--- /dev/null
+++ b/lib/math/rational_kunit.c
@@ -0,0 +1,60 @@
+// 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 > half last term" },
+ { 34567, 100, 120, 20, 120, 1, "Exceeds bounds, semi-convergent term < half last term" },
+ { 1, 30, 100, 10, 0, 1, "Closest to zero" },
+ { 1, 19, 100, 10, 1, 10, "Closest to smallest non-zero" },
+ { 1155, 7735, 255, 255, 33, 221, "Exact answer" },
+ { 27, 32, 16, 16, 11, 13, "Convergent" },
+ { 67, 54, 17, 18, 5, 4, "Convergent, semiconvergent term half convergent term" },
+ { 453, 182, 60, 60, 57, 23, "Semiconvergent, semiconvergent term half convergent term" },
+ { 87, 32, 70, 32, 68, 25, "Semiconvergent, numerator limit" },
+ { 14533, 4626, 15000, 2400, 7433, 2366, "Semiconvergent, demominator 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");
--
2.26.2