diff --git a/libqcdm/tests/ipv6pref.c b/libqcdm/tests/ipv6pref.c
index f5bd71c4..bd0f08f8 100644
--- a/libqcdm/tests/ipv6pref.c
+++ b/libqcdm/tests/ipv6pref.c
@@ -95,16 +95,16 @@ qcdm_send (int fd, char *buf, size_t len)
 
 	while (i < len) {
 		errno = 0;
-		status = write (fd, &buf[i], 1);
-		if (status < 0) {
-			if (errno == EAGAIN) {
+		status = write (fd, &buf[i], len - i);
+		if (status <= 0) {
+			if (errno == EAGAIN || status == 0) {
 				eagain_count--;
 				if (eagain_count <= 0)
 					return FALSE;
 			} else
 				assert (errno == 0);
 		} else
-			i++;
+			i += status;
 
 		usleep (1000);
 	}
diff --git a/libqcdm/tests/modepref.c b/libqcdm/tests/modepref.c
index f8855161..25d3fa11 100644
--- a/libqcdm/tests/modepref.c
+++ b/libqcdm/tests/modepref.c
@@ -95,16 +95,16 @@ qcdm_send (int fd, char *buf, size_t len)
 
 	while (i < len) {
 		errno = 0;
-		status = write (fd, &buf[i], 1);
-		if (status < 0) {
-			if (errno == EAGAIN) {
+		status = write (fd, &buf[i], len - i);
+		if (status <= 0) {
+			if (errno == EAGAIN || status == 0) {
 				eagain_count--;
 				if (eagain_count <= 0)
 					return FALSE;
 			} else
 				assert (errno == 0);
 		} else
-			i++;
+			i += status;
 
 		usleep (1000);
 	}
diff --git a/libqcdm/tests/reset.c b/libqcdm/tests/reset.c
index 079ee386..e4508e43 100644
--- a/libqcdm/tests/reset.c
+++ b/libqcdm/tests/reset.c
@@ -96,16 +96,16 @@ qcdm_send (int fd, char *buf, size_t len)
 
     while (i < len) {
         errno = 0;
-        status = write (fd, &buf[i], 1);
-        if (status < 0) {
-            if (errno == EAGAIN) {
+        status = write (fd, &buf[i], len - i);
+        if (status <= 0) {
+            if (errno == EAGAIN || status == 0) {
                 eagain_count--;
                 if (eagain_count <= 0)
                     return FALSE;
             } else
                 assert (errno == 0);
         } else
-            i++;
+            i += status;
 
         usleep (1000);
     }