diff --git a/nixos/tests/swap-file-btrfs.nix b/nixos/tests/swap-file-btrfs.nix
index d9fcd2be1160..35b9fb4fa50a 100644
--- a/nixos/tests/swap-file-btrfs.nix
+++ b/nixos/tests/swap-file-btrfs.nix
@@ -32,6 +32,8 @@ import ./make-test-python.nix ({ lib, ... }:
 
   testScript = ''
     machine.wait_for_unit('var-swapfile.swap')
+    # Ensure the swap file creation script ran to completion without failing when creating the swap file
+    machine.fail("systemctl is-failed --quiet mkswap-var-swapfile.service")
     machine.succeed("stat --file-system --format=%T /var/swapfile | grep btrfs")
     # First run. Auto creation.
     machine.succeed("swapon --show | grep /var/swapfile")
@@ -41,6 +43,8 @@ import ./make-test-python.nix ({ lib, ... }:
 
     # Second run. Use it as-is.
     machine.wait_for_unit('var-swapfile.swap')
+    # Ensure the swap file creation script ran to completion without failing when the swap file already exists
+    machine.fail("systemctl is-failed --quiet mkswap-var-swapfile.service")
     machine.succeed("swapon --show | grep /var/swapfile")
   '';
 })