[bug#75010,7/7] WIP: gnu: tests: Add module for guix deploy tests.

diff --git a/gnu/tests/deploy.scm b/gnu/tests/deploy.scm
new file mode 100644
index 0000000000..24671cddec
--- /dev/null
+++ b/gnu/tests/deploy.scm
@@ -0,0 +1,203 @@ 
+;;; GNU Guix --- Functional package management for GNU
+;;; Copyright © 2019 Jakob L. Kreuze <zerodaysfordays@sdf.org>
+;;; Copyright © 2024 Herman Rimm <herman@rimm.ee>
+;;;
+;;; This file is part of GNU Guix.
+;;;
+;;; GNU Guix is free software; you can redistribute it and/or modify it
+;;; under the terms of the GNU General Public License as published by
+;;; the Free Software Foundation; either version 3 of the License, or (at
+;;; your option) any later version.
+;;;
+;;; GNU Guix is distributed in the hope that it will be useful, but
+;;; WITHOUT ANY WARRANTY; without even the implied warranty of
+;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+;;; GNU General Public License for more details.
+;;;
+;;; You should have received a copy of the GNU General Public License
+;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
+
+(define-module (gnu tests deploy)
+  #:use-module (gnu packages gnupg)
+  #:use-module ((guix self) #:select (make-config.scm))
+  #:use-module (gnu services)
+  #:use-module (gnu services base)
+  #:use-module (gnu services ssh)
+  #:use-module (gnu system)
+  #:use-module (gnu system vm)
+  #:use-module (gnu tests)
+  #:use-module (guix gexp)
+  #:use-module (guix modules)
+  #:use-module (ice-9 match)
+  #:export (%test-deploy
+            %test-rollback))
+
+;;; Commentary:
+;;;
+;;; Test in-place system deployment: advancing the system generation on
+;;; a running instance of the Guix System.
+;;;
+;;; Code:
+
+(define (machines os)
+  (program-file "machines.scm"
+    #~(list (machine (configuration
+                      (machine-ssh-configuration
+                        (host-name "localhost")
+                        (system (%current-system))))
+                     (environment managed-host-environment-type)
+                     (operating-system #$os)))))
+
+(define not-config?
+  ;; Select (guix …) and (gnu …) modules, except (guix config).
+  (match-lambda
+    (('guix 'config) #f)
+    (('guix rest ...) #t)
+    (('gnu rest ...) #t)
+    (_ #f)))
+
+(define* (deploy-program #:optional (os #~%simple-os))
+  (program-file "deploy.scm"
+    (with-extensions (list guile-gcrypt)
+      (with-imported-modules `(,@(source-module-closure
+                                  '((guix scripts deploy))
+                                  #:select? not-config?)
+                               ((guix config) => ,(make-config.scm)))
+        #~(begin
+            (use-modules (guix scripts deploy))
+            (guix-deploy #$(machines os)))))))
+
+(define os
+  (marionette-operating-system
+    (simple-operating-system
+      (service openssh-service-type
+        (openssh-configuration
+          (permit-root-login #t)
+          (allow-empty-passwords? #t)))
+      (service static-networking-service-type
+        (list (static-networking
+                (inherit %loopback-static-networking)
+                (provision '(networking))))))
+    #:imported-modules '((gnu services herd)
+                         (guix combinators))))
+
+(define vm (virtual-machine os))
+
+(define* (run-deploy-test)
+  "Run a test of an OS running DEPLOY-PROGRAM, which creates a new
+generation of the system profile."
+  (define (test script)
+    (with-imported-modules '((gnu build marionette))
+      #~(begin
+          (use-modules (gnu build marionette)
+                       (srfi srfi-64))
+
+          (define marionette
+            (make-marionette (list #$vm)))
+
+          ;; Return the names of the generation symlinks on MARIONETTE.
+          (define (system-generations marionette)
+            (marionette-eval
+             '(begin
+                (use-modules (ice-9 ftw)
+                             (srfi srfi-1))
+                (let* ((profile-dir "/var/guix/profiles/")
+                       (entries (map first (cddr (file-system-tree profile-dir)))))
+                  (remove (lambda (entry)
+                            (member entry '("per-user" "system")))
+                          entries)))
+             marionette))
+
+          (test-runner-current (system-test-runner #$output))
+          (test-begin "deploy")
+
+          (let ((generations-prior (system-generations marionette)))
+            (test-assert "script successfully evaluated"
+              (marionette-eval
+               '(primitive-load #$script)
+               marionette))
+
+            (test-equal "script created new generation"
+              (length (system-generations marionette))
+              (1+ (length generations-prior)))
+
+            (test-equal "script activated the new generation"
+              (string-append "/var/guix/profiles/system-"
+                             (number->string (+ 1 (length generations-prior)))
+                             "-link")
+              (marionette-eval '(readlink "/run/current-system")
+                               marionette)))
+
+          (test-end))))
+
+  (gexp->derivation "deploy" (test (deploy-program))))
+
+(define* (run-rollback-test)
+  "Run a test of an OS with a faulty bootloader running DEPLOY-PROGRAM,
+which causes a rollback."
+  (define os
+    #~(operating-system
+        (inherit %simple-os)
+        (bootloader
+         (bootloader-configuration
+           (inherit (operating-system-bootloader
+                      %simple-os))
+           (targets '("/dev/null"))))))
+
+  (define (test script)
+    (with-imported-modules '((gnu build marionette))
+      #~(begin
+          (use-modules (gnu build marionette)
+                       (srfi srfi-64))
+
+          (define marionette
+            (make-marionette (list #$vm)))
+
+          ;; Return the names of the generation symlinks on MARIONETTE.
+          (define (system-generations marionette)
+            (marionette-eval
+             '(begin
+                (use-modules (ice-9 ftw)
+                             (srfi srfi-1))
+                (let* ((profile-dir "/var/guix/profiles/")
+                       (entries (map first (cddr (file-system-tree profile-dir)))))
+                  (remove (lambda (entry)
+                            (member entry '("per-user" "system")))
+                          entries)))
+             marionette))
+
+          (test-runner-current (system-test-runner #$output))
+          (test-begin "rollback")
+
+          (let ((generations-prior (system-generations marionette)))
+            (test-assert "script successfully evaluated"
+              (marionette-eval
+               '(primitive-load #$script)
+               marionette))
+
+            (test-equal "script created new generation"
+              (length (system-generations marionette))
+              (1+ (length generations-prior)))
+
+            (test-equal "script rolled back the new generation"
+              (string-append "/var/guix/profiles/system-"
+                             (number->string (length generations-prior))
+                             "-link")
+              (marionette-eval '(readlink "/run/current-system")
+                               marionette)))
+
+          (test-end))))
+
+  (gexp->derivation "rollback" (test (deploy-program os))))
+
+(define %test-deploy
+  (system-test
+   (name "deploy")
+   (description "Deploy to the local machine.")
+   (value (run-deploy-test))))
+
+(define %test-rollback
+  (system-test
+   (name "rollback")
+   (description "Rollback the deployment of a faulty bootloader.")
+   (value (run-rollback-test))))