diff --git a/gnu/local.mk b/gnu/local.mk
index c421da85cba..66cca59839e 100644
--- a/gnu/local.mk
+++ b/gnu/local.mk
@@ -848,6 +848,7 @@ GNU_SYSTEM_MODULES =				\
   %D%/tests/docker.scm				\
   %D%/tests/emacs.scm				\
   %D%/tests/file-sharing.scm			\
+  %D%/tests/foreign.scm				\
   %D%/tests/ganeti.scm				\
   %D%/tests/gdm.scm				\
   %D%/tests/guix.scm				\
diff --git a/gnu/tests/foreign.scm b/gnu/tests/foreign.scm
new file mode 100644
index 00000000000..a08622424a7
--- /dev/null
+++ b/gnu/tests/foreign.scm
@@ -0,0 +1,379 @@
+;;; GNU Guix --- Functional package management for GNU
+;;; Copyright © 2025 Ludovic Courtès <ludo@gnu.org>
+;;;
+;;; 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 foreign)
+  #:use-module (guix download)
+  #:use-module (guix gexp)
+  #:use-module (guix modules)
+  #:use-module (guix monads)
+  #:use-module (guix packages)
+  #:use-module (guix profiles)
+  #:autoload   (guix store) (%store-prefix %store-monad %graft?)
+  #:use-module (gnu compression)
+  #:use-module (gnu tests)
+  #:use-module (gnu packages base)
+  #:use-module (gnu packages bootstrap)
+  #:use-module (gnu packages guile)
+  #:use-module (gnu packages make-bootstrap)
+  #:use-module (gnu packages package-management)
+  #:use-module (gnu packages virtualization)
+  #:use-module (gnu system vm)
+  #:use-module ((guix scripts pack) #:prefix pack:)
+  #:use-module (srfi srfi-9)
+  #:export (%test-debian-install))
+
+(define marionette-systemd-service
+  ;; Definition of the marionette service for systemd.
+  (plain-file "marionette.service" "
+[Unit]
+Description=Guix marionette service
+
+[Install]
+WantedBy=multi-user.target
+
+[Service]
+ExecStart=/opt/guix/bin/guile --no-auto-compile \\
+  /opt/guix/share/guix/marionette-repl.scm\n"))
+
+(define* (qcow-image-with-marionette image
+                                     #:key
+                                     (name "image-with-marionette.qcow2")
+                                     (device "/dev/vdb1"))
+  "Instrument IMAGE, returning a new image that contains a statically-linked
+Guile under /opt/guix and a marionette systemd service.  The relevant file
+system is expected to be on DEVICE."
+  (define vm
+    (virtual-machine
+     (marionette-operating-system %simple-os)))
+
+  (define build
+    (with-imported-modules (source-module-closure
+                            '((guix build utils)
+                              (gnu build marionette)))
+      #~(begin
+          (use-modules (guix build utils)
+                       (gnu build marionette))
+
+          (define target-image
+            #$output)
+
+          (invoke #+(file-append qemu "/bin/qemu-img")
+                  "create" "-b" #$image
+                  "-F" "qcow2" "-f" "qcow2" target-image
+                  "10G")
+
+          ;; Run a VM that will mount IMAGE and populate it.  This is somewhat
+          ;; more convenient to set up than 'guestfish' from libguestfs.
+          (let ((marionette
+                 (make-marionette
+                  (list #$vm "-drive"
+                        (string-append "file=" target-image
+                                       ",format=qcow2,if=virtio,"
+                                       "cache=writeback,werror=report,readonly=off")))))
+
+            (marionette-eval '(system* "mount" #$device "/mnt")
+                             marionette)
+            (marionette-eval '(system* "ls" "-la" "/mnt")
+                             marionette)
+            (marionette-eval '(begin
+                                (use-modules (guix build utils))
+                                (mkdir-p "/mnt/opt/guix")
+                                (copy-recursively #$%guile-static-initrd
+                                                  "/mnt/opt/guix"
+                                                  #:log (%make-void-port "w")
+                                                  #:keep-mtime? #t))
+                             marionette)
+            (marionette-eval '(system* "/mnt/opt/guix/bin/guile" "--version")
+                             marionette)
+            (unless (= 42 (status:exit-val
+                           (marionette-eval '(system* "/mnt/opt/guix/bin/guile"
+                                                      "-c" "(exit 42)")
+                                            marionette)))
+              (error "statically-linked Guile is broken"))
+
+            ;; Install the marionette systemd service and activate it.
+            (marionette-eval '(begin
+                                (mkdir-p "/mnt/opt/guix/share/guix")
+                                (copy-file #$(marionette-program)
+                                           "/mnt/opt/guix/share/guix/marionette-repl.scm")
+
+                                (mkdir-p "/mnt/etc/systemd/system")
+                                (copy-file #$marionette-systemd-service
+                                           "/mnt/etc/systemd/system/marionette.service")
+
+                                ;; Activate the service, as per 'systemctl
+                                ;; enable marionette.service'.
+                                (symlink
+                                 "/etc/systemd/system/marionette.service"
+                                 "/mnt/etc/systemd/system/multi-user.target.wants/marionette.service"))
+                             marionette)
+
+            (unless (zero? (marionette-eval '(system* "umount" "/mnt")
+                                            marionette))
+              (error "failed to unmount device"))))))
+
+  (computed-file name build))
+
+(define (manifest-entry-without-grafts entry)
+  "Return ENTRY with grafts disabled on its contents."
+  (manifest-entry
+    (inherit entry)
+    (item (with-parameters ((%graft? #f))
+            (manifest-entry-item entry)))))
+
+(define %installation-tarball-manifest
+  ;; Manifest of the Guix installation tarball.
+  (concatenate-manifests
+   (list (packages->manifest (list guix))
+
+         ;; Include the dependencies of 'hello' in addition to 'guix' so that
+         ;; we can test 'guix build hello'.
+         (map-manifest-entries
+          manifest-entry-without-grafts
+          (package->development-manifest hello))
+
+         ;; Add the source of 'hello'.
+         (manifest
+          (list (manifest-entry
+                  (name "hello-source")
+                  (version (package-version hello))
+                  (item (let ((file (origin-actual-file-name
+                                     (package-source hello))))
+                          (computed-file
+                           "hello-source"
+                           #~(begin
+                               ;; Put the tarball in a subdirectory since
+                               ;; profile union crashes otherwise.
+                               (mkdir #$output)
+                               (mkdir (in-vicinity #$output "src"))
+                               (symlink #$(package-source hello)
+                                        (in-vicinity #$output
+                                                     (string-append "src/"
+                                                                    #$file))))))))))
+
+         ;; Include 'guile-final', which is needed when building derivations
+         ;; such as that of 'hello' but missing from the development manifest.
+         ;; Add '%bootstrap-guile', used by 'guix install --bootstrap'.
+         (map-manifest-entries
+          manifest-entry-without-grafts
+          (packages->manifest (list (canonical-package guile-3.0)
+                                    %bootstrap-guile))))))
+
+(define %guix-install-script
+  ;; The 'guix-install.sh' script.
+  ;;
+  ;; To test local changes, replace the expression below with:
+  ;;
+  ;;   (local-file "../../etc/guix-install.sh")
+  ;;
+  ;; This cannot be done unconditionally since that file does not exists in
+  ;; inferiors.
+  (file-append (package-source guix) "/etc/guix-install.sh"))
+
+(define (run-foreign-install-test image name)
+  "Run an installation of Guix in IMAGE, the QCOW2 image of a systemd-based
+GNU/Linux distro, and check that the installation is functional."
+  (define instrumented-image
+    (qcow-image-with-marionette image
+                                #:name (string-append name ".qcow2")))
+
+  (define (test tarball)
+    (with-imported-modules (source-module-closure
+                            '((gnu build marionette)
+                              (gnu system file-systems)))
+      #~(begin
+          (use-modules (gnu build marionette)
+                       (gnu system file-systems)
+                       (srfi srfi-64)
+                       (ice-9 match))
+
+          (define marionette
+            (make-marionette
+             (list (string-append #$qemu-minimal "/bin/" (qemu-command))
+                   #$@(common-qemu-options instrumented-image
+                                           (list (%store-prefix))
+                                           #:image-format "qcow2"
+                                           #:rw-image? #t)
+                   "-m" "512"
+                   "-snapshot")))
+
+          (test-runner-current (system-test-runner #$output))
+          (test-begin "foreign-install")
+
+          (test-equal "marionette works"
+            "Linux"
+            (marionette-eval '(utsname:sysname (uname))
+                             marionette))
+
+          (test-assert "/etc/os-release"
+            (marionette-eval '(begin
+                                (use-modules (ice-9 textual-ports))
+                                (call-with-input-file "/etc/os-release"
+                                  get-string-all))
+                             marionette))
+
+          (test-equal "mount host file store"
+            0
+            (marionette-eval
+             '(begin
+                (mkdir "/host")
+                (system* "mount" "-t" "9p"
+                         "-o" "trans=virtio,cache=loose,ro"
+                         #$(file-system->mount-tag (%store-prefix))
+                         "/host"))
+             marionette))
+
+          (test-assert "screenshot before"
+            (marionette-control (string-append "screendump " #$output
+                                               "/before-install.ppm")
+                                marionette))
+
+          (test-assert "install fake dependencies"
+            ;; The installation script insists on checking for the
+            ;; availability of 'wget' and 'gpg' but does not actually use them
+            ;; when 'GUIX_BINARY_FILE_NAME' is set.  Provide fake binaries.
+            (marionette-eval '(begin
+                                (symlink "/bin/true" "/bin/wget")
+                                (symlink "/bin/true" "/bin/gpg")
+                                #t)
+                             marionette))
+
+          (test-assert "run install script"
+            (marionette-eval '(system
+                               (string-append
+                                "yes '' | GUIX_BINARY_FILE_NAME="
+                                (in-vicinity "/host"
+                                             (basename #$tarball))
+                                " sh "
+                                (in-vicinity
+                                 "/host"
+                                 (string-drop #$%guix-install-script
+                                              #$(string-length
+                                                 (%store-prefix))))))
+                             marionette))
+
+          (test-equal "hello not already built"
+            #f
+            ;; Check that the next test will really build 'hello'.
+            (marionette-eval '(file-exists?
+                               #$(with-parameters ((%graft? #f))
+                                   hello))
+                             marionette))
+
+          (test-equal "guix build hello"
+            0
+            ;; Check that guix-daemon is up and running and that the build
+            ;; environment is properly set up (build users, etc.).
+            (marionette-eval '(system* "guix" "build" "hello" "--no-grafts")
+                             marionette))
+
+          (test-assert "hello indeed built"
+            (marionette-eval '(file-exists?
+                               #$(with-parameters ((%graft? #f))
+                                   hello))
+                             marionette))
+
+          (test-equal "guix install hello"
+            0
+            ;; Check that ~/.guix-profile & co. are properly created.
+            (marionette-eval '(let ((pw (getpwuid (getuid))))
+                                (setenv "USER" (passwd:name pw))
+                                (setenv "HOME" (pk 'home (passwd:dir pw)))
+                                (system* "guix" "install" "hello"
+                                         "--no-grafts" "--bootstrap"))
+                             marionette))
+
+          (test-equal "user profile created"
+            0
+            (marionette-eval '(system "ls -lad ~/.guix-profile")
+                             marionette))
+
+          (test-equal "hello"
+            0
+            (marionette-eval '(system "~/.guix-profile/bin/hello")
+                             marionette))
+
+          (test-equal "create user account"
+            0
+            (marionette-eval '(system* "useradd" "-d" "/home/user" "-m"
+                                       "user")
+                             marionette))
+
+          (test-equal "guix install hello, unprivileged user"
+            0
+            ;; Check that 'guix' is in $PATH for new users and that
+            ;; ~user/.guix-profile also gets created.
+            (marionette-eval '(system "su - user -c \
+'guix install hello --no-grafts --bootstrap'")
+                             marionette))
+
+          (test-equal "user hello"
+            0
+            (marionette-eval '(system "~user/.guix-profile/bin/hello")
+                             marionette))
+
+          (test-equal "unprivileged user profile created"
+            0
+            (marionette-eval '(system "ls -lad ~user/.guix-profile")
+                             marionette))
+
+          (test-equal "store is read-only"
+            EROFS
+            (marionette-eval '(catch 'system-error
+                                (lambda ()
+                                  (mkdir (in-vicinity #$(%store-prefix)
+                                                      "whatever"))
+                                  0)
+                                (lambda args
+                                  (system-error-errno args)))
+                             marionette))
+
+          (test-assert "screenshot after"
+            (marionette-control (string-append "screendump " #$output
+                                               "/after-install.ppm")
+                                marionette))
+
+          (test-end))))
+
+  (mlet* %store-monad ((profile (profile-derivation
+                                 %installation-tarball-manifest))
+                       (tarball (pack:self-contained-tarball
+                                 "guix-binary" profile
+                                 #:compressor (lookup-compressor "zstd")
+                                 #:profile-name "current-guix"
+                                 #:localstatedir? #t)))
+    (gexp->derivation name (test tarball))))
+
+(define debian-12-qcow2
+  ;; Image taken from <https://www.debian.org/distrib/>.
+  ;; XXX: Those images are periodically removed from debian.org.
+  (origin
+    (uri
+     "https://cloud.debian.org/images/cloud/bookworm/20250210-2019/debian-12-nocloud-amd64-20250210-2019.qcow2")
+    (method url-fetch)
+    (sha256
+     (base32
+      "06vlcq2dzgczlyp9lfkkdf3dgvfjp22lh5xz0mnl0bdgzq61sykb"))))
+
+(define %test-debian-install
+  (system-test
+   (name "debian-install")
+   (description
+    "Test installation of Guix on Debian using the @file{guix-install.sh}
+script.")
+   (value (run-foreign-install-test debian-12-qcow2 name))))
