nixos/tests/hibernate: install a system instead

Rather than relying on carefully avoiding touching the 9P-mounted
/nix/store, we instead install a small NixOS system, similar to
the installer tests, and boot from that.

This avoids the various pitfalls associated with trying to unsuspend
properly and trades off a bunch of boilerplate for what will hopefully
be a more reliable test.

Additionally, this test now actually tests booting the system using a
bootloader, rather than the previous method of just booting the kernel
directly.

nixos/tests/hibernate.nix

@@ -1,44 +1,120 @@
 # Test whether hibernation from partition works.
 
-import ./make-test-python.nix (pkgs: {
+{ system ? builtins.currentSystem
+, config ? {}
+, pkgs ? import ../.. { inherit system config; }
+}:
+
+with import ../lib/testing-python.nix { inherit system pkgs; };
+
+let
+  # System configuration of the installed system, which is used for the actual
+  # hibernate testing.
+  installedConfig = with pkgs.lib; {
+    imports = [
+      ../modules/testing/test-instrumentation.nix
+      ../modules/profiles/qemu-guest.nix
+      ../modules/profiles/minimal.nix
+    ];
+
+    hardware.enableAllFirmware = mkForce false;
+    documentation.nixos.enable = false;
+    boot.loader.grub.device = "/dev/vda";
+
+    systemd.services.backdoor.conflicts = [ "sleep.target" ];
+
+    powerManagement.resumeCommands = "systemctl --no-block restart backdoor.service";
+
+    fileSystems = {
+      "/".device = "/dev/vda2";
+    };
+    swapDevices = mkOverride 0 [ { device = "/dev/vda1"; } ];
+  };
+  installedSystem = (import ../lib/eval-config.nix {
+    inherit system;
+    modules = [ installedConfig ];
+  }).config.system.build.toplevel;
+in makeTest {
   name = "hibernate";
 
   nodes = {
+    # System configuration used for installing the installedConfig from above.
     machine = { config, lib, pkgs, ... }: with lib; {
-      virtualisation.emptyDiskImages = [ config.virtualisation.memorySize ];
+      imports = [
+        ../modules/profiles/installation-device.nix
+        ../modules/profiles/base.nix
+      ];
 
-      systemd.services.backdoor.conflicts = [ "sleep.target" ];
+      nix.binaryCaches = mkForce [ ];
+      nix.extraOptions = ''
+        hashed-mirrors =
+        connect-timeout = 1
+      '';
 
-      swapDevices = mkOverride 0 [ { device = "/dev/vdb"; } ];
-
-      networking.firewall.allowedTCPPorts = [ 4444 ];
-
-      systemd.services.listener.serviceConfig.ExecStart = "${pkgs.netcat}/bin/nc -l 4444 -k";
-    };
-
-    probe = { pkgs, ...}: {
-      environment.systemPackages = [ pkgs.netcat ];
+      virtualisation.diskSize = 8 * 1024;
+      virtualisation.emptyDiskImages = [
+        # Small root disk for installer
+        512
+      ];
+      virtualisation.bootDevice = "/dev/vdb";
     };
   };
 
   # 9P doesn't support reconnection to virtio transport after a hibernation.
   # Therefore, machine just hangs on any Nix store access.
-  # To work around it we run a daemon which listens to a TCP connection and
-  # try to connect to it as a test.
+  # To avoid this, we install NixOS onto a temporary disk with everything we need
+  # included into the store.
 
   testScript =
     ''
+      def create_named_machine(name):
+          return create_machine(
+              {
+                  "qemuFlags": "-cpu max ${
+                    if system == "x86_64-linux" then "-m 1024"
+                    else "-m 768 -enable-kvm -machine virt,gic-version=host"}",
+                  "hdaInterface": "virtio",
+                  "hda": "vm-state-machine/machine.qcow2",
+                  "name": name,
+              }
+          )
+
+
+      # Install NixOS
       machine.start()
-      machine.wait_for_unit("multi-user.target")
-      machine.succeed("mkswap /dev/vdb")
-      machine.succeed("swapon -a")
-      machine.start_job("listener")
-      machine.wait_for_open_port(4444)
-      machine.succeed("systemctl hibernate &")
-      machine.wait_for_shutdown()
-      probe.wait_for_unit("multi-user.target")
-      machine.start()
-      probe.wait_until_succeeds("echo test | nc machine 4444 -N")
+      machine.succeed(
+          # Partition /dev/vda
+          "flock /dev/vda parted --script /dev/vda -- mklabel msdos"
+          + " mkpart primary linux-swap 1M 1024M"
+          + " mkpart primary ext2 1024M -1s",
+          "udevadm settle",
+          "mkfs.ext3 -L nixos /dev/vda2",
+          "mount LABEL=nixos /mnt",
+          "mkswap /dev/vda1 -L swap",
+          # Install onto /mnt
+          "nix-store --load-db < ${pkgs.closureInfo {rootPaths = [installedSystem];}}/registration",
+          "nixos-install --root /mnt --system ${installedSystem} --no-root-passwd",
+      )
+      machine.shutdown()
+
+      # Start up
+      hibernate = create_named_machine("hibernate")
+
+      # Drop in file that checks if we un-hibernated properly (and not booted fresh)
+      hibernate.succeed(
+          "mkdir /run/test",
+          "mount -t ramfs -o size=1m ramfs /run/test",
+          "echo not persisted to disk > /run/test/suspended",
+      )
+
+      # Hibernate machine
+      hibernate.succeed("systemctl hibernate &")
+      hibernate.wait_for_shutdown()
+
+      # Restore machine from hibernation, validate our ramfs file is there.
+      resume = create_named_machine("resume")
+      resume.start()
+      resume.succeed("grep 'not persisted to disk' /run/test/suspended")
     '';
 
-})
+}