--- /dev/null
+#include "clar_libgit2.h"
+
+static void assert_found(const char *haystack, const char *needle, size_t expected_pos)
+{
+ cl_assert_equal_p(git__memmem(haystack, haystack ? strlen(haystack) : 0,
+ needle, needle ? strlen(needle) : 0),
+ haystack + expected_pos);
+}
+
+static void assert_absent(const char *haystack, const char *needle)
+{
+ cl_assert_equal_p(git__memmem(haystack, haystack ? strlen(haystack) : 0,
+ needle, needle ? strlen(needle) : 0),
+ NULL);
+}
+
+void test_memmem__found(void)
+{
+ assert_found("a", "a", 0);
+ assert_found("ab", "a", 0);
+ assert_found("ba", "a", 1);
+ assert_found("aa", "a", 0);
+ assert_found("aab", "aa", 0);
+ assert_found("baa", "aa", 1);
+ assert_found("dabc", "abc", 1);
+ assert_found("abababc", "abc", 4);
+}
+
+void test_memmem__absent(void)
+{
+ assert_absent("a", "b");
+ assert_absent("a", "aa");
+ assert_absent("ba", "ab");
+ assert_absent("ba", "ab");
+ assert_absent("abc", "abcd");
+ assert_absent("abcabcabc", "bcac");
+}
+
+void test_memmem__edgecases(void)
+{
+ assert_absent(NULL, NULL);
+ assert_absent("a", NULL);
+ assert_absent(NULL, "a");
+ assert_absent("", "a");
+ assert_absent("a", "");
+}