diff --git a/lib/label/label.c b/lib/label/label.c
index c11a040a9..4b18f5682 100644
--- a/lib/label/label.c
+++ b/lib/label/label.c
@@ -922,6 +922,9 @@ bool dev_write_bytes(struct device *dev, off_t start, size_t len, void *data)
 {
 	int ret;
 
+	if (test_mode())
+		return true;
+
 	if (!scan_bcache) {
 		if (!dev_open(dev))
 			return false;
@@ -955,6 +958,9 @@ bool dev_write_zeros(struct device *dev, off_t start, size_t len)
 {
 	int ret;
 
+	if (test_mode())
+		return true;
+
 	if (!scan_bcache) {
 		if (!dev_open(dev))
 			return false;