add a simple test program

Makefile

@@ -30,6 +30,9 @@ $(DEB): build
 	cd build; dpkg-buildpackage -b -us -uc --no-pre-clean
 	lintian $(DEB)
 
+test: test.c proxmox-backup-qemu.h
+	gcc test.c -o test -lc  -Wl,-rpath=./target/debug -L ./target/debug/ -l proxmox_backup_qemu
+
 distclean: clean
 
 clean:

test.c

@@ -0,0 +1,22 @@
+#include "stdio.h"
+#include "stdlib.h"
+#include "proxmox-backup-qemu.h"
+
+void test_cb(void *data) {
+    printf("callback called\n");
+}
+
+void main(void) {
+
+  printf("This is a test\n");
+  ProxmoxBackupHandle *pbs = proxmox_backup_connect();
+
+  printf("Start write\n");
+  proxmox_backup_write_data_async(pbs, NULL, 0, test_cb, NULL);
+
+  printf("Join\n");
+  proxmox_backup_disconnect(pbs);
+
+  printf("Done\n");
+  exit(0);
+}