tests/dbusrunner: Use separate HOME, Temp and XDG Runtime dirs

We need to use a different $XDG_RUNTIME_DIR path to be able to start most
tests in parallel, and we can use a temporary directory for that which python
cleans up when done.

Also, given that most of settings are stored in HOME use temporary one
for that too, to prevent mutter to fail because it may load some local
configuration (e.g. monitors.xml) that don't meet the expectations or
that may change the test behavior in an unexpected way.

As per this, CI needs to be adapted for new args handling

Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/3793>

.gitlab-ci.yml

@@ -518,6 +518,7 @@ build-wayland-only@x86_64:
         ./src/tests/meta-dbus-runner.py
           --launch=pipewire
           --launch=wireplumber
+          --
           meson test
             -C build
             --setup plain
@@ -680,6 +681,7 @@ dist-mutter:
         ./src/tests/meta-dbus-runner.py
           --launch=pipewire
           --launch=wireplumber
+          --
           meson dist -C build
   artifacts:
     expire_in: 7 day

src/tests/kvm/meson.build

@@ -50,7 +50,7 @@ foreach test_case: privileged_tests
     args: [
       kernel_image_path,
       meta_dbus_runner.full_path(),
-      '--kvm',
+      '--kvm --',
       meson.current_build_dir(),
       vm_env,
       kvm_wrapper,

src/tests/kvm/virtme-run.sh

@@ -40,6 +40,10 @@ SCRIPT="\
   $(printf "\"%s\" " "${@:6}")\
 "
 
+if [ -v "$MUTTER_TEST_ROOT" ]; then
+  ISOLATE_DIRS_ARGS="--rwdir=$MUTTER_TEST_ROOT"
+fi
+
 echo Running tests in virtual machine ...
 virtme-run \
   --memory=1024M \
@@ -47,6 +51,7 @@ virtme-run \
   --pwd \
   --kimg "$IMAGE" \
   --script-sh "sh -c \"$SCRIPT\"" \
+  $ISOLATE_DIRS_ARGS \
   --qemu-opts -cpu host,pdcm=off -smp 2
 VM_RESULT=$?
 if [ $VM_RESULT != 0 ]; then

src/tests/mutter_dbusrunner.py

@@ -8,6 +8,7 @@ import subprocess
 import getpass
 import argparse
 import logind_helpers
+import tempfile
 from collections import OrderedDict
 from dbusmock import DBusTestCase
 from dbus.mainloop.glib import DBusGMainLoop
@@ -286,12 +287,38 @@ def meta_run(klass):
     parser = argparse.ArgumentParser()
     parser.add_argument('--kvm', action='store_true', default=False)
     parser.add_argument('--launch', action='append', default=[])
+    parser.add_argument('--no-isolate-dirs', action='store_true', default=False)
     (args, rest) = parser.parse_known_args(sys.argv)
 
     rest.pop(0)
+    if not rest:
+        parser.error('Command or separator `--` not found')
     if rest[0] == '--':
-      rest.pop(0)
+        rest.pop(0)
+    else:
+        print('WARNING: Command or separator `--` not found', file=sys.stderr)
 
+    if args.no_isolate_dirs:
+        return meta_run_klass(klass, args, rest)
+
+    test_root = os.getenv('MUTTER_DBUS_RUNNER_TEST_ROOT')
+    if test_root:
+        print('Reusing MUTTER_DBUS_RUNNER_TEST_ROOT', test_root, file=sys.stderr)
+        return meta_run_klass(klass, args, rest)
+
+    with tempfile.TemporaryDirectory(prefix='mutter-testroot-',
+                                     ignore_cleanup_errors=True) as test_root:
+        env_dirs = ['HOME', 'TMPDIR', 'XDG_RUNTIME_DIR', 'XDG_CONFIG_DIR']
+        os.environ['MUTTER_DBUS_RUNNER_TEST_ROOT'] = test_root
+        print('Setup MUTTER_DBUS_RUNNER_TEST_ROOT as', test_root, file=sys.stderr)
+        for env_dir in env_dirs:
+            directory = os.path.join(test_root, env_dir.lower())
+            os.mkdir(directory, mode=0o700)
+            os.environ[env_dir] = directory
+            print('Setup', env_dir, 'as', directory, file=sys.stderr)
+        return meta_run_klass(klass, args, rest)
+
+def meta_run_klass(klass, args, rest):
     result = 1
 
     if os.getenv('META_DBUS_RUNNER_ACTIVE') == None: