tests: install: Fix gui-installed-desktop-os-encrypted test.

* gnu/tests/base.scm (run-basic-test): Add a 'desktop?' argument. Wait 30
seconds before trying to switch to TTY1 on desktop.
* gnu/tests/install.scm (guided-installation-test): Use 512MiB of RAM and pass
the desktop argument to "run-basic-test".

gnu/tests/base.scm

@@ -55,7 +55,10 @@
 
 
 (define* (run-basic-test os command #:optional (name "basic")
-                         #:key initialization root-password)
+                         #:key
+                         initialization
+                         root-password
+                         desktop?)
   "Return a derivation called NAME that tests basic features of the OS started
 using COMMAND, a gexp that evaluates to a list of strings.  Compare some
 properties of running system to what's declared in OS, an <operating-system>.
@@ -300,6 +303,12 @@ info --version")
           (test-equal "login on tty1"
             "root\n"
             (begin
+              ;; XXX: On desktop, GDM3 will switch to TTY7. If this happens
+              ;; after we switched to TTY1, we won't be able to login. Make
+              ;; sure to wait long enough before switching to TTY1.
+              (when #$desktop?
+                (sleep 30))
+
               (marionette-control "sendkey ctrl-alt-f1" marionette)
               ;; Wait for the 'term-tty1' service to be running (using
               ;; 'start-service' is the simplest and most reliable way to do

gnu/tests/install.scm

@@ -1317,10 +1317,11 @@ build (current-guix) and then store a couple of full system images.")
                                   marionette
                                   #:desktop? desktop?
                                   #:encrypted? encrypted?))))
-         (command (qemu-command/writable-image image)))
+         (command (qemu-command/writable-image image #:memory-size 512)))
       (run-basic-test target-os command name
                       #:initialization (and encrypted? enter-luks-passphrase)
-                      #:root-password %root-password)))))
+                      #:root-password %root-password
+                      #:desktop? desktop?)))))
 
 (define %test-gui-installed-os
   (guided-installation-test