From eecb6c2bd82e7b2db3cc91c2cd0fbeddaa78eced Mon Sep 17 00:00:00 2001
From: oxalica <oxalicc@pm.me>
Date: Tue, 4 Oct 2022 11:08:46 +0800
Subject: [PATCH] nixos/tests/swap-file-btrfs: init

---
 nixos/tests/all-tests.nix       |  1 +
 nixos/tests/swap-file-btrfs.nix | 46 +++++++++++++++++++++++++++++++++
 2 files changed, 47 insertions(+)
 create mode 100644 nixos/tests/swap-file-btrfs.nix

diff --git a/nixos/tests/all-tests.nix b/nixos/tests/all-tests.nix
index 8227f606d16..d61c40ad845 100644
--- a/nixos/tests/all-tests.nix
+++ b/nixos/tests/all-tests.nix
@@ -619,6 +619,7 @@ in {
   strongswan-swanctl = handleTest ./strongswan-swanctl.nix {};
   stunnel = handleTest ./stunnel.nix {};
   sudo = handleTest ./sudo.nix {};
+  swap-file-btrfs = handleTest ./swap-file-btrfs.nix {};
   swap-partition = handleTest ./swap-partition.nix {};
   sway = handleTest ./sway.nix {};
   switchTest = handleTest ./switch-test.nix {};
diff --git a/nixos/tests/swap-file-btrfs.nix b/nixos/tests/swap-file-btrfs.nix
new file mode 100644
index 00000000000..4f73942b5f3
--- /dev/null
+++ b/nixos/tests/swap-file-btrfs.nix
@@ -0,0 +1,46 @@
+import ./make-test-python.nix ({ lib, ... }:
+{
+  name = "swap-file-btrfs";
+
+  meta.maintainers = with lib.maintainers; [ oxalica ];
+
+  nodes.machine =
+    { pkgs, ... }:
+    {
+      virtualisation.useDefaultFilesystems = false;
+
+      virtualisation.bootDevice = "/dev/vda";
+
+      boot.initrd.postDeviceCommands = ''
+        ${pkgs.btrfs-progs}/bin/mkfs.btrfs --label root /dev/vda
+      '';
+
+      virtualisation.fileSystems = {
+        "/" = {
+          device = "/dev/disk/by-label/root";
+          fsType = "btrfs";
+        };
+      };
+
+      swapDevices = [
+        {
+          device = "/var/swapfile";
+          size = 1; # 1MiB.
+        }
+      ];
+    };
+
+  testScript = ''
+    machine.wait_for_unit('var-swapfile.swap')
+    machine.succeed("stat --file-system --format=%T /var/swapfile | grep btrfs")
+    # First run. Auto creation.
+    machine.succeed("swapon --show | grep /var/swapfile")
+
+    machine.shutdown()
+    machine.start()
+
+    # Second run. Use it as-is.
+    machine.wait_for_unit('var-swapfile.swap')
+    machine.succeed("swapon --show | grep /var/swapfile")
+  '';
+})