{example,tests}: add hybrid-tmpfs-on-root

example/hybrid-tmpfs-on-root.nix

@@ -0,0 +1,52 @@
+{ disks ? [ "/dev/sda" ], ... }:
+{
+  disk.main = {
+    device = builtins.elemAt disks 0;
+    type = "disk";
+    content = {
+      type = "table";
+      format = "gpt";
+      partitions = [
+        {
+          name = "boot";
+          type = "partition";
+          start = "0";
+          end = "1M";
+          flags = [ "bios_grub" ];
+        }
+        {
+          type = "partition";
+          name = "ESP";
+          start = "1M";
+          end = "512M";
+          bootable = true;
+          content = {
+            type = "filesystem";
+            format = "vfat";
+            mountpoint = "/boot";
+          };
+        }
+        {
+          name = "nix";
+          type = "partition";
+          start = "512M";
+          end = "100%";
+          part-type = "primary";
+          content = {
+            type = "filesystem";
+            format = "ext4";
+            mountpoint = "/nix";
+          };
+        }
+      ];
+    };
+  };
+  nodev."/" = {
+    fsType = "tmpfs";
+    mountOptions = [
+      "size=2G"
+      "defaults"
+      "mode=755"
+    ];
+  };
+}

tests/hybrid-tmpfs-on-root.nix

@@ -0,0 +1,10 @@
+{ pkgs ? (import <nixpkgs> { })
+, makeDiskoTest ? (pkgs.callPackage ./lib.nix { }).makeDiskoTest
+}:
+makeDiskoTest {
+  disko-config = ../example/hybrid-tmpfs-on-root.nix;
+  extraTestScript = ''
+    machine.succeed("mountpoint /");
+    machine.succeed("findmnt / --types tmpfs");
+  '';
+}