tests: Use null-co:// instead of /dev/null as the dummy image

Signed-off-by: NFam Zheng <famz@redhat.com>
Reviewed-by: NMax Reitz <mreitz@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

tests/drive_del-test.c

@@ -92,7 +92,7 @@ static void test_after_failed_device_add(void)
 static void test_drive_del_device_del(void)
 {
     /* Start with a drive used by a device that unplugs instantaneously */
-    qtest_start("-drive if=none,id=drive0,file=/dev/null,format=raw"
+    qtest_start("-drive if=none,id=drive0,file=null-co://,format=raw"
                 " -device virtio-scsi-pci"
                 " -device scsi-hd,drive=drive0,id=dev0");
 

tests/nvme-test.c

@@ -22,7 +22,7 @@ int main(int argc, char **argv)
     g_test_init(&argc, &argv, NULL);
     qtest_add_func("/nvme/nop", nop);
 
-    qtest_start("-drive id=drv0,if=none,file=/dev/null,format=raw "
+    qtest_start("-drive id=drv0,if=none,file=null-co://,format=raw "
                 "-device nvme,drive=drv0,serial=foo");
     ret = g_test_run();
 

tests/usb-hcd-uhci-test.c

@@ -79,7 +79,7 @@ int main(int argc, char **argv)
 {
     const char *arch = qtest_get_arch();
     const char *cmd = "-device piix3-usb-uhci,id=uhci,addr=1d.0"
-                      " -drive id=drive0,if=none,file=/dev/null,format=raw"
+                      " -drive id=drive0,if=none,file=null-co://,format=raw"
                       " -device usb-tablet,bus=uhci.0,port=1";
     int ret;
 

tests/usb-hcd-xhci-test.c

@@ -89,7 +89,7 @@ int main(int argc, char **argv)
     qtest_add_func("/xhci/pci/hotplug/usb-uas", test_usb_uas_hotplug);
 
     qtest_start("-device nec-usb-xhci,id=xhci"
-                " -drive id=drive0,if=none,file=/dev/null,format=raw");
+                " -drive id=drive0,if=none,file=null-co://,format=raw");
     ret = g_test_run();
     qtest_end();
 

tests/virtio-blk-test.c

@@ -63,7 +63,7 @@ static QOSState *pci_test_start(void)
     const char *arch = qtest_get_arch();
     char *tmp_path;
     const char *cmd = "-drive if=none,id=drive0,file=%s,format=raw "
-                      "-drive if=none,id=drive1,file=/dev/null,format=raw "
+                      "-drive if=none,id=drive1,file=null-co://,format=raw "
                       "-device virtio-blk-pci,id=drv0,drive=drive0,"
                       "addr=%x.%x";
 

tests/virtio-scsi-test.c

@@ -35,7 +35,7 @@ typedef struct {
 static QOSState *qvirtio_scsi_start(const char *extra_opts)
 {
     const char *arch = qtest_get_arch();
-    const char *cmd = "-drive id=drv0,if=none,file=/dev/null,format=raw "
+    const char *cmd = "-drive id=drv0,if=none,file=null-co://,format=raw "
                       "-device virtio-scsi-pci,id=vs0 "
                       "-device scsi-hd,bus=vs0.0,drive=drv0 %s";
 
@@ -195,7 +195,8 @@ static void hotplug(void)
     QDict *response;
     QOSState *qs;
 
-    qs = qvirtio_scsi_start("-drive id=drv1,if=none,file=/dev/null,format=raw");
+    qs = qvirtio_scsi_start(
+            "-drive id=drv1,if=none,file=null-co://,format=raw");
     response = qmp("{\"execute\": \"device_add\","
                    " \"arguments\": {"
                    "   \"driver\": \"scsi-hd\","