nixos/test-driver: handle decoding errors in Machine.execute

The output of a command is not guaranteed to be valid UTF-8, so the
decoding can fail raising UnicodeDecodeError. If this happens during a
`succeeds` the check will be erroneously marked failed.

This changes the error handling to the "replace" mode, where invalid
codepoints are replaced with � (REPLACEMENT CHARACTER U+FFFD) and the
decoding can go on.

1 files changed, 1 insertions, 1 deletions

diff --git a/nixos/lib/test-driver/test_driver/machine.py b/nixos/lib/test-driver/test_driver/machine.py
index 1c77550bd1fd0..0db7930f496b2 100644
--- a/nixos/lib/test-driver/test_driver/machine.py
+++ b/nixos/lib/test-driver/test_driver/machine.py
@@ -545,7 +545,7 @@ class Machine:
         self.shell.send("echo ${PIPESTATUS[0]}\n".encode())
         rc = int(self._next_newline_closed_block_from_shell().strip())
 
-        return (rc, output.decode())
+        return (rc, output.decode(errors="replace"))
 
     def shell_interact(self, address: Optional[str] = None) -> None:
         """Allows you to interact with the guest shell for debugging purposes.