+static void test_uid_ptr(void) {
+
+ assert_se(UID_TO_PTR(0) != NULL);
+ assert_se(UID_TO_PTR(1000) != NULL);
+
+ assert_se(PTR_TO_UID(UID_TO_PTR(0)) == 0);
+ assert_se(PTR_TO_UID(UID_TO_PTR(1000)) == 1000);
+}
+
+static void test_sparse_write_one(int fd, const char *buffer, size_t n) {
+ char check[n];
+
+ assert_se(lseek(fd, 0, SEEK_SET) == 0);
+ assert_se(ftruncate(fd, 0) >= 0);
+ assert_se(sparse_write(fd, buffer, n, 4) == (ssize_t) n);
+
+ assert_se(lseek(fd, 0, SEEK_CUR) == (off_t) n);
+ assert_se(ftruncate(fd, n) >= 0);
+
+ assert_se(lseek(fd, 0, SEEK_SET) == 0);
+ assert_se(read(fd, check, n) == (ssize_t) n);
+
+ assert_se(memcmp(buffer, check, n) == 0);
+}
+
+static void test_sparse_write(void) {
+ const char test_a[] = "test";
+ const char test_b[] = "\0\0\0\0test\0\0\0\0";
+ const char test_c[] = "\0\0test\0\0\0\0";
+ const char test_d[] = "\0\0test\0\0\0test\0\0\0\0test\0\0\0\0\0test\0\0\0test\0\0\0\0test\0\0\0\0\0\0\0\0";
+ const char test_e[] = "test\0\0\0\0test";
+ _cleanup_close_ int fd = -1;
+ char fn[] = "/tmp/sparseXXXXXX";
+
+ fd = mkostemp(fn, O_CLOEXEC);
+ assert_se(fd >= 0);
+ unlink(fn);
+
+ test_sparse_write_one(fd, test_a, sizeof(test_a));
+ test_sparse_write_one(fd, test_b, sizeof(test_b));
+ test_sparse_write_one(fd, test_c, sizeof(test_c));
+ test_sparse_write_one(fd, test_d, sizeof(test_d));
+ test_sparse_write_one(fd, test_e, sizeof(test_e));
+}
+