diff --git a/src/main.rs b/src/main.rs
index ba98571..3d09fa5 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -180,6 +180,13 @@ fn get_hostname() -> Option<String> {
 }
 
 fn get_machine_id() -> Option<Uuid> {
+    #[cfg(debug_assertions)]
+    if let Ok(v) = std::env::var("SSHCA_CLI_DEBUG_TEST_MACHINE_ID") {
+        if let Ok(u) = Uuid::parse_str(&v) {
+            return Some(u);
+        }
+    };
+
     match std::fs::read_to_string(RPI_SERIAL_PATH) {
         Ok(s) => match Uuid::parse_str(&format!(
             "{:0>32}",