написал bit_count, тесты и добавил цель в Makefile

bit_test.c

@@ -0,0 +1,30 @@
+#include "munit.h"
+#include "bit_lib.h"
+
+static MunitResult
+test_bit_count_basic(const MunitParameter params[], void *data) {
+    (void) params; (void) data;
+
+    munit_assert_int(bit_count(0), ==, 0);          // 0b0
+    munit_assert_int(bit_count(1), ==, 1);          // 0b1
+    munit_assert_int(bit_count(2), ==, 1);          // 0b10
+    munit_assert_int(bit_count(3), ==, 2);          // 0b11
+    munit_assert_int(bit_count(15), ==, 4);         // 0b1111
+    munit_assert_int(bit_count(16), ==, 1);         // 0b10000
+    munit_assert_int(bit_count(255), ==, 8);        // 0b11111111
+
+    return MUNIT_OK;
+}
+
+static const MunitTest tests[] = {
+    { "/bit_count/basic", test_bit_count_basic, NULL, NULL, MUNIT_TEST_OPTION_NONE, NULL },
+    { NULL, NULL, NULL, NULL, MUNIT_TEST_OPTION_NONE, NULL }
+};
+
+static const MunitSuite suite = {
+   NULL, tests, NULL, 1, MUNIT_SUITE_OPTION_NONE
+};
+
+int main(int argc, const char *argv[]) {
+    return munit_suite_main(&suite, (void*) "", argc, (char * const*) argv);
+}