diff --git a/tests/unit-test-client.c b/tests/unit-test-client.c
index a06a16a..c399a4f 100644
--- a/tests/unit-test-client.c
+++ b/tests/unit-test-client.c
@@ -600,6 +600,8 @@ int main(int argc, char *argv[])
     /* Restore original timeout */
     modbus_set_timeout_begin(ctx, &timeout_begin_old);
 
+    /* Wait for data before flushing */
+    usleep(100);
     modbus_flush(ctx);
 
     /** BAD RESPONSE **/