diff --git a/flake.nix b/flake.nix
index 8abb4e6..79be931 100644
--- a/flake.nix
+++ b/flake.nix
@@ -30,6 +30,8 @@
         ];
       };
 
+      testPkgs = import nixpkgs-test { system = "x86_64-linux"; };
+
       inherit (pkgs) lib;
 
       rust-nightly = pkgs.rust-bin.fromRustupToolchainFile ./rust/lanzaboote/rust-toolchain.toml;
@@ -128,160 +130,12 @@
         ];
       };
 
-      checks.x86_64-linux =
-        let
-          mkSecureBootTest = { name, machine ? { }, testScript }: nixpkgs-test.legacyPackages.x86_64-linux.nixosTest {
-            inherit name testScript;
-            nodes.machine = { lib, ... }: {
-              imports = [
-                self.nixosModules.lanzaboote
-                machine
-              ];
-
-              nixpkgs.overlays = [ self.overlays.default ];
-
-              virtualisation = {
-                useBootLoader = true;
-                useEFIBoot = true;
-                useSecureBoot = true;
-              };
-
-              boot.loader.efi = {
-                canTouchEfiVariables = true;
-              };
-              boot.lanzaboote = {
-                enable = true;
-                enrollKeys = lib.mkDefault true;
-                pkiBundle = ./pki;
-              };
-            };
-          };
-
-          # Execute a boot test that is intended to fail.
-          #
-          mkUnsignedTest = { name, path, appendCrap ? false }: mkSecureBootTest {
-            inherit name;
-            testScript = ''
-              import json
-              import os.path
-              bootspec = None
-
-              def convert_to_esp(store_file_path):
-                  store_dir = os.path.basename(os.path.dirname(store_file_path))
-                  filename = os.path.basename(store_file_path)
-                  return f'/boot/EFI/nixos/{store_dir}-{filename}.efi'
-
-              machine.start()
-              bootspec = json.loads(machine.succeed("cat /run/current-system/boot.json")).get('v1')
-              assert bootspec is not None, "Unsupported bootspec version!"
-              src_path = ${path.src}
-              dst_path = ${path.dst}
-              machine.succeed(f"cp -rf {src_path} {dst_path}")
-            '' + lib.optionalString appendCrap ''
-              machine.succeed(f"echo Foo >> {dst_path}")
-            '' +
-            ''
-              machine.succeed("sync")
-              machine.crash()
-              machine.start()
-              machine.wait_for_console_text("Hash mismatch")
-            '';
-          };
-        in
-        {
-          lanzatool-clippy = lanzatoolCrane.clippy;
-          lanzaboote-clippy = lanzabooteCrane.clippy;
-
-          # TODO: user mode: OK
-          # TODO: how to get in: {deployed, audited} mode ?
-          lanzaboote-boot = mkSecureBootTest {
-            name = "signed-files-boot-under-secureboot";
-            testScript = ''
-              machine.start()
-              assert "Secure Boot: enabled (user)" in machine.succeed("bootctl status")
-            '';
-          };
-
-          lanzaboote-boot-under-sd-stage1 = mkSecureBootTest {
-            name = "signed-files-boot-under-secureboot-systemd-stage-1";
-            machine = _: {
-              boot.initrd.systemd.enable = true;
-            };
-            testScript = ''
-              machine.start()
-              assert "Secure Boot: enabled (user)" in machine.succeed("bootctl status")
-            '';
-          };
-
-          # So, this is the responsibility of the lanzatool install
-          # to run the append-initrd-secret script
-          # This test assert that lanzatool still do the right thing
-          # preDeviceCommands should not have any root filesystem mounted
-          # so it should not be able to find /etc/iamasecret, other than the
-          # initrd's one.
-          # which should exist IF lanzatool do the right thing.
-          lanzaboote-with-initrd-secrets = mkSecureBootTest {
-            name = "signed-files-boot-with-secrets-under-secureboot";
-            machine = _: {
-              boot.initrd.secrets = {
-                "/etc/iamasecret" = pkgs.writeText "iamsecret" "this is a very secure secret";
-              };
-
-              boot.initrd.preDeviceCommands = ''
-                grep "this is a very secure secret" /etc/iamasecret
-              '';
-            };
-            testScript = ''
-              machine.start()
-              assert "Secure Boot: enabled (user)" in machine.succeed("bootctl status")
-            '';
-          };
-
-          # The initrd is not directly signed. Its hash is embedded
-          # into lanzaboote. To make integrity verification fail, we
-          # actually have to modify the initrd. Appending crap to the
-          # end is a harmless way that would make the kernel still
-          # accept it.
-          is-initrd-secured = mkUnsignedTest {
-            name = "unsigned-initrd-do-not-boot-under-secureboot";
-            path = {
-              src = "bootspec.get('initrd')";
-              dst = "convert_to_esp(bootspec.get('initrd'))";
-            };
-            appendCrap = true;
-          };
-
-          is-kernel-secured = mkUnsignedTest {
-            name = "unsigned-kernel-do-not-boot-under-secureboot";
-            path = {
-              src = "bootspec.get('kernel')";
-              dst = "convert_to_esp(bootspec.get('kernel'))";
-            };
-          };
-          specialisation-works = mkSecureBootTest {
-            name = "specialisation-still-boot-under-secureboot";
-            machine = { pkgs, ... }: {
-              specialisation.variant.configuration = {
-                environment.systemPackages = [
-                  pkgs.efibootmgr
-                ];
-              };
-            };
-            testScript = ''
-              machine.start()
-              print(machine.succeed("ls -lah /boot/EFI/Linux"))
-              print(machine.succeed("cat /run/current-system/boot.json"))
-              # TODO: make it more reliable to find this filename, i.e. read it from somewhere?
-              machine.succeed("bootctl set-default nixos-generation-1-specialisation-variant.efi")
-              machine.succeed("sync")
-              machine.fail("efibootmgr")
-              machine.crash()
-              machine.start()
-              print(machine.succeed("bootctl"))
-              # We have efibootmgr in this specialisation.
-              machine.succeed("efibootmgr")
-            '';
-          };
-        };
+      checks.x86_64-linux = {
+        lanzatool-clippy = lanzatoolCrane.clippy;
+        lanzaboote-clippy = lanzabooteCrane.clippy;
+      } // (import ./nix/tests/lanzaboote.nix {
+        inherit pkgs testPkgs;
+        lanzabooteModule = self.nixosModules.lanzaboote;
+      });
     };
 }
diff --git a/nix/tests/lanzaboote.nix b/nix/tests/lanzaboote.nix
new file mode 100644
index 0000000..2ec5b96
--- /dev/null
+++ b/nix/tests/lanzaboote.nix
@@ -0,0 +1,156 @@
+{ pkgs
+, testPkgs
+, lanzabooteModule
+}:
+
+let
+  inherit (pkgs) lib;
+
+  mkSecureBootTest = { name, machine ? { }, testScript }: testPkgs.nixosTest {
+    inherit name testScript;
+    nodes.machine = { lib, ... }: {
+      imports = [
+        lanzabooteModule
+        machine
+      ];
+
+      virtualisation = {
+        useBootLoader = true;
+        useEFIBoot = true;
+        useSecureBoot = true;
+      };
+
+      boot.loader.efi = {
+        canTouchEfiVariables = true;
+      };
+      boot.lanzaboote = {
+        enable = true;
+        enrollKeys = lib.mkDefault true;
+        pkiBundle = ../../pki;
+      };
+    };
+  };
+
+  # Execute a boot test that is intended to fail.
+  #
+  mkUnsignedTest = { name, path, appendCrap ? false }: mkSecureBootTest {
+    inherit name;
+    testScript = ''
+      import json
+      import os.path
+      bootspec = None
+
+      def convert_to_esp(store_file_path):
+          store_dir = os.path.basename(os.path.dirname(store_file_path))
+          filename = os.path.basename(store_file_path)
+          return f'/boot/EFI/nixos/{store_dir}-{filename}.efi'
+
+      machine.start()
+      bootspec = json.loads(machine.succeed("cat /run/current-system/boot.json")).get('v1')
+      assert bootspec is not None, "Unsupported bootspec version!"
+      src_path = ${path.src}
+      dst_path = ${path.dst}
+      machine.succeed(f"cp -rf {src_path} {dst_path}")
+    '' + lib.optionalString appendCrap ''
+      machine.succeed(f"echo Foo >> {dst_path}")
+    '' +
+    ''
+      machine.succeed("sync")
+      machine.crash()
+      machine.start()
+      machine.wait_for_console_text("Hash mismatch")
+    '';
+  };
+in
+{
+  # TODO: user mode: OK
+  # TODO: how to get in: {deployed, audited} mode ?
+  lanzaboote-boot = mkSecureBootTest {
+    name = "signed-files-boot-under-secureboot";
+    testScript = ''
+      machine.start()
+      assert "Secure Boot: enabled (user)" in machine.succeed("bootctl status")
+    '';
+  };
+
+  lanzaboote-boot-under-sd-stage1 = mkSecureBootTest {
+    name = "signed-files-boot-under-secureboot-systemd-stage-1";
+    machine = { ... }: {
+      boot.initrd.systemd.enable = true;
+    };
+    testScript = ''
+      machine.start()
+      assert "Secure Boot: enabled (user)" in machine.succeed("bootctl status")
+    '';
+  };
+
+  # So, this is the responsibility of the lanzatool install
+  # to run the append-initrd-secret script
+  # This test assert that lanzatool still do the right thing
+  # preDeviceCommands should not have any root filesystem mounted
+  # so it should not be able to find /etc/iamasecret, other than the
+  # initrd's one.
+  # which should exist IF lanzatool do the right thing.
+  lanzaboote-with-initrd-secrets = mkSecureBootTest {
+    name = "signed-files-boot-with-secrets-under-secureboot";
+    machine = { ... }: {
+      boot.initrd.secrets = {
+        "/etc/iamasecret" = (pkgs.writeText "iamsecret" "this is a very secure secret");
+      };
+
+      boot.initrd.preDeviceCommands = ''
+        grep "this is a very secure secret" /etc/iamasecret
+      '';
+    };
+    testScript = ''
+      machine.start()
+      assert "Secure Boot: enabled (user)" in machine.succeed("bootctl status")
+    '';
+  };
+
+  # The initrd is not directly signed. Its hash is embedded
+  # into lanzaboote. To make integrity verification fail, we
+  # actually have to modify the initrd. Appending crap to the
+  # end is a harmless way that would make the kernel still
+  # accept it.
+  is-initrd-secured = mkUnsignedTest {
+    name = "unsigned-initrd-do-not-boot-under-secureboot";
+    path = {
+      src = "bootspec.get('initrd')";
+      dst = "convert_to_esp(bootspec.get('initrd'))";
+    };
+    appendCrap = true;
+  };
+
+  is-kernel-secured = mkUnsignedTest {
+    name = "unsigned-kernel-do-not-boot-under-secureboot";
+    path = {
+      src = "bootspec.get('kernel')";
+      dst = "convert_to_esp(bootspec.get('kernel'))";
+    };
+  };
+  specialisation-works = mkSecureBootTest {
+    name = "specialisation-still-boot-under-secureboot";
+    machine = { pkgs, ... }: {
+      specialisation.variant.configuration = {
+        environment.systemPackages = [
+          pkgs.efibootmgr
+        ];
+      };
+    };
+    testScript = ''
+      machine.start()
+      print(machine.succeed("ls -lah /boot/EFI/Linux"))
+      print(machine.succeed("cat /run/current-system/boot.json"))
+      # TODO: make it more reliable to find this filename, i.e. read it from somewhere?
+      machine.succeed("bootctl set-default nixos-generation-1-specialisation-variant.efi")
+      machine.succeed("sync")
+      machine.fail("efibootmgr")
+      machine.crash()
+      machine.start()
+      print(machine.succeed("bootctl"))
+      # We have efibootmgr in this specialisation.
+      machine.succeed("efibootmgr")
+    '';
+  };
+}