add ext4 as rootfsType

tests/ci.nix

@@ -3,7 +3,8 @@
   pseudofiles = import ./pseudofiles/test.nix;
   wlan = import ./wlan/test.nix;
   pppoe = import ./pppoe/test.nix;
-  jffs2 =  import ./jffs2/test.nix;
+  jffs2 = import ./jffs2/test.nix;
+  ext4 = import ./ext4/test.nix;
   min-copy-closure =  import ./min-copy-closure/test.nix;
   fennel = import ./fennel/test.nix;
 }

tests/ext4/configuration.nix

@@ -0,0 +1,19 @@
+{ config, pkgs, lib, ... } :
+let
+  inherit (pkgs.pseudofile) dir symlink;
+in {
+  imports = [
+    ../../vanilla-configuration.nix
+    ../../modules/squashfs.nix
+    ../../modules/ext4fs.nix
+  ];
+  config.rootfsType = "ext4";
+  config.filesystem = dir {
+    hello = {
+      type = "f";
+      uid = 7;
+      gid = 24;
+      file = "hello world";
+    };
+  };
+}

tests/ext4/script.expect

@@ -0,0 +1,11 @@
+set timeout 10
+
+spawn socat unix-connect:vm/console -
+send "\r\n"
+expect "login:" {  send "root\r\n" }
+expect "#"
+send "echo HELLO WORLD > /hello\r\n"
+expect "#"
+send "cat /hello\r\n"
+expect 'HELLO WORLD'
+close

tests/ext4/test.nix

@@ -0,0 +1,19 @@
+{
+  liminix
+, nixpkgs
+}:
+let img = (import liminix {
+      device = import "${liminix}/devices/qemu/";
+      liminix-config = ./configuration.nix;
+    }).outputs.vmroot;
+    pkgs = import <nixpkgs> { overlays = [(import ../../overlay.nix)]; };
+in pkgs.runCommand "check" {
+  nativeBuildInputs = with pkgs; [
+    expect
+    socat
+  ] ;
+} ''
+mkdir vm
+${img}/run.sh --background ./vm
+expect ${./script.expect} >$out
+''