1 files changed, 52 insertions, 0 deletions
diff --git a/src/test/test-io-util.c b/src/test/test-io-util.c
new file mode 100644
index 0000000..104c022
--- /dev/null
+++ b/src/test/test-io-util.c
@@ -0,0 +1,52 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include <fcntl.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+#include "alloc-util.h"
+#include "fd-util.h"
+#include "io-util.h"
+#include "macro.h"
+
+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));
+}
+
+int main(void) {
+        test_sparse_write();
+
+        return 0;
+}