gio/gtestdbus.c

   1 /* GIO testing utilities
   2  *
   3  * Copyright (C) 2008-2010 Red Hat, Inc.
   4  * Copyright (C) 2012 Collabora Ltd. <http://www.collabora.co.uk/>
   5  *
   6  * This library is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU Lesser General Public
   8  * License as published by the Free Software Foundation; either
   9  * version 2 of the License, or (at your option) any later version.
  10  *
  11  * This library is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General
  17  * Public License along with this library; if not, write to the
  18  * Free Software Foundation, Inc., 59 Temple Place, Suite 330,
  19  * Boston, MA 02111-1307, USA.
  20  *
  21  * Authors: David Zeuthen <davidz@redhat.com>
  22  *          Xavier Claessens <xavier.claessens@collabora.co.uk>
  23  */
  24
  25 #include "config.h"
  26
  27 #include <stdlib.h>
  28 #include <stdio.h>
  29 #include <gstdio.h>
  30 #ifdef HAVE_UNISTD_H
  31 #include <unistd.h>
  32 #endif
  33 #ifdef G_OS_WIN32
  34 #include <io.h>
  35 #endif
  36
  37 #include <glib.h>
  38
  39 #include "gdbusconnection.h"
  40 #include "gdbusprivate.h"
  41 #include "gfile.h"
  42 #include "gioenumtypes.h"
  43 #include "gtestdbus.h"
  44
  45 #include "glibintl.h"
  46
  47 #ifdef G_OS_WIN32
  48 #include <windows.h>
  49 #endif
  50
  51 /* -------------------------------------------------------------------------- */
  52 /* Utility: Wait until object has a single ref  */
  53
  54 typedef struct
  55 {
  56   GMainLoop *loop;
  57   gboolean   timed_out;
  58 } WeakNotifyData;
  59
  60 static gboolean
  61 on_weak_notify_timeout (gpointer user_data)
  62 {
  63   WeakNotifyData *data = user_data;
  64   data->timed_out = TRUE;
  65   g_main_loop_quit (data->loop);
  66   return FALSE;
  67 }
  68
  69 static gboolean
  70 unref_on_idle (gpointer object)
  71 {
  72   g_object_unref (object);
  73   return FALSE;
  74 }
  75
  76 static gboolean
  77 _g_object_unref_and_wait_weak_notify (gpointer object)
  78 {
  79   WeakNotifyData data;
  80   guint timeout_id;
  81
  82   data.loop = g_main_loop_new (NULL, FALSE);
  83   data.timed_out = FALSE;
  84
  85   g_object_weak_ref (object, (GWeakNotify) g_main_loop_quit, data.loop);
  86
  87   /* Drop the ref in an idle callback, this is to make sure the mainloop
  88    * is already running when weak notify happens */
  89   g_idle_add (unref_on_idle, object);
  90
  91   /* Make sure we don't block forever */
  92   timeout_id = g_timeout_add (30 * 1000, on_weak_notify_timeout, &data);
  93
  94   g_main_loop_run (data.loop);
  95
  96   g_source_remove (timeout_id);
  97
  98   if (data.timed_out)
  99     {
 100       g_warning ("Weak notify timeout, object ref_count=%d\n",
 101           G_OBJECT (object)->ref_count);
 102     }
 103
 104   return data.timed_out;
 105 }
 106
 107 /* -------------------------------------------------------------------------- */
 108 /* Utilities to cleanup the mess in the case unit test process crash */
 109
 110 #ifdef G_OS_WIN32
 111
 112 /* This could be interesting to expose in public API */
 113 static void
 114 _g_test_watcher_add_pid (GPid pid)
 115 {
 116   static gsize started = 0;
 117   HANDLE job;
 118
 119   if (g_once_init_enter (&started))
 120     {
 121       JOBOBJECT_EXTENDED_LIMIT_INFORMATION info;
 122
 123       job = CreateJobObjectW (NULL, NULL);
 124       memset (&info, 0, sizeof (info));
 125       info.BasicLimitInformation.LimitFlags = 0x2000 /* JOB_OBJECT_LIMIT_KILL_ON_JOB_CLOSE */;
 126
 127       if (!SetInformationJobObject(job, JobObjectExtendedLimitInformation, &info, sizeof (info)))
 128         g_warning ("Can't enable JOB_OBJECT_LIMIT_KILL_ON_JOB_CLOSE: %s", g_win32_error_message (GetLastError()));
 129
 130       g_once_init_leave (&started,(gsize)job);
 131     }
 132
 133   job = (HANDLE)started;
 134
 135   if (!AssignProcessToJobObject(job, pid))
 136     g_warning ("Can't assign process to job: %s", g_win32_error_message (GetLastError()));
 137 }
 138
 139 static void
 140 _g_test_watcher_remove_pid (GPid pid)
 141 {
 142   /* No need to unassign the process from the job object as the process
 143      will be killed anyway */
 144 }
 145
 146 #else
 147
 148 #define ADD_PID_FORMAT "add pid %d\n"
 149 #define REMOVE_PID_FORMAT "remove pid %d\n"
 150
 151 static void
 152 watch_parent (gint fd)
 153 {
 154   GIOChannel *channel;
 155   GPollFD fds[1];
 156   GArray *pids_to_kill;
 157
 158   channel = g_io_channel_unix_new (fd);
 159
 160   fds[0].fd = fd;
 161   fds[0].events = G_IO_HUP | G_IO_IN;
 162   fds[0].revents = 0;
 163
 164   pids_to_kill = g_array_new (FALSE, FALSE, sizeof (guint));
 165
 166   do
 167     {
 168       gint num_events;
 169       gchar *command = NULL;
 170       guint pid;
 171       guint n;
 172       GError *error = NULL;
 173
 174       num_events = g_poll (fds, 1, -1);
 175       if (num_events == 0)
 176         continue;
 177
 178       if (fds[0].revents == G_IO_HUP)
 179         {
 180           /* Parent quit, cleanup the mess and exit */
 181           for (n = 0; n < pids_to_kill->len; n++)
 182             {
 183               pid = g_array_index (pids_to_kill, guint, n);
 184               g_print ("cleaning up pid %d\n", pid);
 185               kill (pid, SIGTERM);
 186             }
 187
 188           g_array_unref (pids_to_kill);
 189           g_io_channel_shutdown (channel, FALSE, &error);
 190           g_assert_no_error (error);
 191           g_io_channel_unref (channel);
 192
 193           exit (0);
 194         }
 195
 196       /* Read the command from the input */
 197       g_io_channel_read_line (channel, &command, NULL, NULL, &error);
 198       g_assert_no_error (error);
 199
 200       /* Check for known commands */
 201       if (sscanf (command, ADD_PID_FORMAT, &pid) == 1)
 202         {
 203           g_array_append_val (pids_to_kill, pid);
 204         }
 205       else if (sscanf (command, REMOVE_PID_FORMAT, &pid) == 1)
 206         {
 207           for (n = 0; n < pids_to_kill->len; n++)
 208             {
 209               if (g_array_index (pids_to_kill, guint, n) == pid)
 210                 {
 211                   g_array_remove_index (pids_to_kill, n);
 212                   pid = 0;
 213                   break;
 214                 }
 215             }
 216           if (pid != 0)
 217             {
 218               g_warning ("unknown pid %d to remove", pid);
 219             }
 220         }
 221       else
 222         {
 223           g_warning ("unknown command from parent '%s'", command);
 224         }
 225
 226       g_free (command);
 227     }
 228   while (TRUE);
 229 }
 230
 231 static GIOChannel *
 232 watcher_init (void)
 233 {
 234   static gsize started = 0;
 235   static GIOChannel *channel = NULL;
 236
 237   if (g_once_init_enter (&started))
 238     {
 239       gint pipe_fds[2];
 240
 241       /* fork a child to clean up when we are killed */
 242       if (pipe (pipe_fds) != 0)
 243         {
 244           g_warning ("pipe() failed: %m");
 245           g_assert_not_reached ();
 246         }
 247
 248       switch (fork ())
 249         {
 250         case -1:
 251           g_warning ("fork() failed: %m");
 252           g_assert_not_reached ();
 253           break;
 254
 255         case 0:
 256           /* child */
 257           close (pipe_fds[1]);
 258           watch_parent (pipe_fds[0]);
 259           break;
 260
 261         default:
 262           /* parent */
 263           close (pipe_fds[0]);
 264           channel = g_io_channel_unix_new (pipe_fds[1]);
 265         }
 266
 267       g_once_init_leave (&started, 1);
 268     }
 269
 270   return channel;
 271 }
 272
 273 static void
 274 watcher_send_command (const gchar *command)
 275 {
 276   GIOChannel *channel;
 277   GError *error = NULL;
 278
 279   channel = watcher_init ();
 280
 281   g_io_channel_write_chars (channel, command, -1, NULL, &error);
 282   g_assert_no_error (error);
 283
 284   g_io_channel_flush (channel, &error);
 285   g_assert_no_error (error);
 286 }
 287
 288 /* This could be interesting to expose in public API */
 289 static void
 290 _g_test_watcher_add_pid (GPid pid)
 291 {
 292   gchar *command;
 293
 294   command = g_strdup_printf (ADD_PID_FORMAT, (guint) pid);
 295   watcher_send_command (command);
 296   g_free (command);
 297 }
 298
 299 static void
 300 _g_test_watcher_remove_pid (GPid pid)
 301 {
 302   gchar *command;
 303
 304   command = g_strdup_printf (REMOVE_PID_FORMAT, (guint) pid);
 305   watcher_send_command (command);
 306   g_free (command);
 307 }
 308
 309 #endif
 310
 311 /* -------------------------------------------------------------------------- */
 312 /* GTestDBus object implementation */
 313
 314 /**
 315  * SECTION:gtestdbus
 316  * @short_description: D-Bus testing helper
 317  * @include: gio/gio.h
 318  *
 319  * A helper class for testing code which uses D-Bus without touching the user's
 320  * session bus.
 321  */
 322
 323 typedef struct _GTestDBusClass   GTestDBusClass;
 324 typedef struct _GTestDBusPrivate GTestDBusPrivate;
 325
 326 /**
 327  * GTestDBus:
 328  *
 329  * The #GTestDBus structure contains only private data and
 330  * should only be accessed using the provided API.
 331  *
 332  * Since: 2.34
 333  */
 334 struct _GTestDBus {
 335   GObject parent;
 336
 337   GTestDBusPrivate *priv;
 338 };
 339
 340 struct _GTestDBusClass {
 341   GObjectClass parent_class;
 342 };
 343
 344 struct _GTestDBusPrivate
 345 {
 346   GTestDBusFlags flags;
 347   GPtrArray *service_dirs;
 348   GPid bus_pid;
 349   gchar *bus_address;
 350   gboolean up;
 351 };
 352
 353 enum
 354 {
 355   PROP_0,
 356   PROP_FLAGS,
 357 };
 358
 359 G_DEFINE_TYPE (GTestDBus, g_test_dbus, G_TYPE_OBJECT)
 360
 361 static void
 362 g_test_dbus_init (GTestDBus *self)
 363 {
 364   self->priv = G_TYPE_INSTANCE_GET_PRIVATE ((self), G_TYPE_TEST_DBUS,
 365       GTestDBusPrivate);
 366
 367   self->priv->service_dirs = g_ptr_array_new_with_free_func (g_free);
 368 }
 369
 370 static void
 371 g_test_dbus_dispose (GObject *object)
 372 {
 373   GTestDBus *self = (GTestDBus *) object;
 374
 375   if (self->priv->up)
 376     g_test_dbus_down (self);
 377
 378   G_OBJECT_CLASS (g_test_dbus_parent_class)->dispose (object);
 379 }
 380
 381 static void
 382 g_test_dbus_finalize (GObject *object)
 383 {
 384   GTestDBus *self = (GTestDBus *) object;
 385
 386   g_ptr_array_unref (self->priv->service_dirs);
 387   g_free (self->priv->bus_address);
 388
 389   G_OBJECT_CLASS (g_test_dbus_parent_class)->finalize (object);
 390 }
 391
 392 static void
 393 g_test_dbus_get_property (GObject *object,
 394     guint property_id,
 395     GValue *value,
 396     GParamSpec *pspec)
 397 {
 398   GTestDBus *self = (GTestDBus *) object;
 399
 400   switch (property_id)
 401     {
 402       case PROP_FLAGS:
 403         g_value_set_flags (value, g_test_dbus_get_flags (self));
 404         break;
 405       default:
 406         G_OBJECT_WARN_INVALID_PROPERTY_ID (object, property_id, pspec);
 407         break;
 408     }
 409 }
 410
 411 static void
 412 g_test_dbus_set_property (GObject *object,
 413     guint property_id,
 414     const GValue *value,
 415     GParamSpec *pspec)
 416 {
 417   GTestDBus *self = (GTestDBus *) object;
 418
 419   switch (property_id)
 420     {
 421       case PROP_FLAGS:
 422         self->priv->flags = g_value_get_flags (value);
 423         break;
 424       default:
 425         G_OBJECT_WARN_INVALID_PROPERTY_ID (object, property_id, pspec);
 426         break;
 427     }
 428 }
 429
 430 static void
 431 g_test_dbus_class_init (GTestDBusClass *klass)
 432 {
 433   GObjectClass *object_class = G_OBJECT_CLASS (klass);
 434
 435   object_class->dispose = g_test_dbus_dispose;
 436   object_class->finalize = g_test_dbus_finalize;
 437   object_class->get_property = g_test_dbus_get_property;
 438   object_class->set_property = g_test_dbus_set_property;
 439
 440   g_type_class_add_private (object_class, sizeof (GTestDBusPrivate));
 441
 442   /**
 443    * GTestDBus:flags:
 444    *
 445    * #GTestDBusFlags specifying the behaviour of the dbus session
 446    *
 447    * Since: 2.34
 448    */
 449   g_object_class_install_property (object_class, PROP_FLAGS,
 450     g_param_spec_flags ("flags",
 451                         P_("dbus session flags"),
 452                         P_("Flags specifying the behaviour of the dbus session"),
 453                         G_TYPE_TEST_DBUS_FLAGS, G_TEST_DBUS_NONE,
 454                         G_PARAM_READWRITE | G_PARAM_CONSTRUCT_ONLY |
 455                         G_PARAM_STATIC_STRINGS));
 456
 457 }
 458
 459 static gchar *
 460 write_config_file (GTestDBus *self)
 461 {
 462   GString *contents;
 463   gint fd;
 464   guint i;
 465   GError *error = NULL;
 466   gchar *path = NULL;
 467
 468   fd = g_file_open_tmp ("g-test-dbus-XXXXXX", &path, &error);
 469   g_assert_no_error (error);
 470
 471   contents = g_string_new (NULL);
 472   g_string_append (contents,
 473       "<busconfig>\n"
 474       "  <type>session</type>\n"
 475 #ifdef G_OS_WIN32
 476       "  <listen>nonce-tcp:</listen>\n"
 477 #else
 478       "  <listen>unix:tmpdir=/tmp</listen>\n"
 479 #endif
 480                    );
 481
 482   for (i = 0; i < self->priv->service_dirs->len; i++)
 483     {
 484       const gchar *path = g_ptr_array_index (self->priv->service_dirs, i);
 485
 486       g_string_append_printf (contents,
 487           "  <servicedir>%s</servicedir>\n", path);
 488     }
 489
 490   g_string_append (contents,
 491       "  <policy context=\"default\">\n"
 492       "    <!-- Allow everything to be sent -->\n"
 493       "    <allow send_destination=\"*\" eavesdrop=\"true\"/>\n"
 494       "    <!-- Allow everything to be received -->\n"
 495       "    <allow eavesdrop=\"true\"/>\n"
 496       "    <!-- Allow anyone to own anything -->\n"
 497       "    <allow own=\"*\"/>\n"
 498       "  </policy>\n"
 499       "</busconfig>\n");
 500
 501   g_file_set_contents (path, contents->str, contents->len, &error);
 502   g_assert_no_error (error);
 503
 504   g_string_free (contents, TRUE);
 505
 506   close (fd);
 507
 508   return path;
 509 }
 510
 511 static void
 512 start_daemon (GTestDBus *self)
 513 {
 514   gchar *argv[] = {"dbus-daemon", "--print-address", "--config-file=foo", NULL};
 515   gchar *config_path;
 516   gchar *config_arg;
 517   gint stdout_fd;
 518   GIOChannel *channel;
 519   gsize termpos;
 520   GError *error = NULL;
 521
 522   if (g_getenv ("G_TEST_DBUS_DAEMON") != NULL)
 523     argv[0] = (gchar *)g_getenv ("G_TEST_DBUS_DAEMON");
 524
 525   /* Write config file and set its path in argv */
 526   config_path = write_config_file (self);
 527   config_arg = g_strdup_printf ("--config-file=%s", config_path);
 528   argv[2] = config_arg;
 529
 530   /* Spawn dbus-daemon */
 531   g_spawn_async_with_pipes (NULL,
 532                             argv,
 533                             NULL,
 534 #ifdef G_OS_WIN32
 535                             /* We Need this to get the pid returned on win32 */
 536                             G_SPAWN_DO_NOT_REAP_CHILD |
 537 #endif
 538                             G_SPAWN_SEARCH_PATH,
 539                             NULL,
 540                             NULL,
 541                             &self->priv->bus_pid,
 542                             NULL,
 543                             &stdout_fd,
 544                             NULL,
 545                             &error);
 546   g_assert_no_error (error);
 547
 548   _g_test_watcher_add_pid (self->priv->bus_pid);
 549
 550   /* Read bus address from daemon' stdout */
 551   channel = g_io_channel_unix_new (stdout_fd);
 552   g_io_channel_read_line (channel, &self->priv->bus_address, NULL,
 553       &termpos, &error);
 554   g_assert_no_error (error);
 555   self->priv->bus_address[termpos] = '\0';
 556
 557   /* start dbus-monitor */
 558   if (g_getenv ("G_DBUS_MONITOR") != NULL)
 559     {
 560       gchar *command;
 561
 562       command = g_strdup_printf ("dbus-monitor --address %s",
 563           self->priv->bus_address);
 564       g_spawn_command_line_async (command, NULL);
 565       g_free (command);
 566
 567       g_usleep (500 * 1000);
 568     }
 569
 570   /* Cleanup */
 571   g_io_channel_shutdown (channel, FALSE, &error);
 572   g_assert_no_error (error);
 573   g_io_channel_unref (channel);
 574
 575   /* Don't use g_file_delete since it calls into gvfs */
 576   if (g_unlink (config_path) != 0)
 577     g_assert_not_reached ();
 578
 579   g_free (config_path);
 580   g_free (config_arg);
 581 }
 582
 583 static void
 584 stop_daemon (GTestDBus *self)
 585 {
 586 #ifdef G_OS_WIN32
 587   if (!TerminateProcess (self->priv->bus_pid, 0))
 588     g_warning ("Can't terminate process: %s", g_win32_error_message (GetLastError()));
 589 #else
 590   kill (self->priv->bus_pid, SIGTERM);
 591 #endif
 592   _g_test_watcher_remove_pid (self->priv->bus_pid);
 593   g_spawn_close_pid (self->priv->bus_pid);
 594   self->priv->bus_pid = 0;
 595
 596   g_free (self->priv->bus_address);
 597   self->priv->bus_address = NULL;
 598 }
 599
 600 /**
 601  * g_test_dbus_new:
 602  * @flags: a #GTestDBusFlags
 603  *
 604  * Create a new #GTestDBus object.
 605  *
 606  * Returns: (transfer full): a new #GTestDBus.
 607  */
 608 GTestDBus *
 609 g_test_dbus_new (GTestDBusFlags flags)
 610 {
 611   return g_object_new (G_TYPE_TEST_DBUS,
 612       "flags", flags,
 613       NULL);
 614 }
 615
 616 /**
 617  * g_test_dbus_get_flags:
 618  * @self: a #GTestDBus
 619  *
 620  * Gets the flags of the #GTestDBus object.
 621  *
 622  * Returns: the value of #GTestDBus:flags property
 623  */
 624 GTestDBusFlags
 625 g_test_dbus_get_flags (GTestDBus *self)
 626 {
 627   g_return_val_if_fail (G_IS_TEST_DBUS (self), G_TEST_DBUS_NONE);
 628
 629   return self->priv->flags;
 630 }
 631
 632 /**
 633  * g_test_dbus_get_bus_address:
 634  * @self: a #GTestDBus
 635  *
 636  * Get the address on which dbus-daemon is running. if g_test_dbus_up() has not
 637  * been called yet, %NULL is returned. This can be used with
 638  * g_dbus_connection_new_for_address()
 639  *
 640  * Returns: the address of the bus, or %NULL.
 641  */
 642 const gchar *
 643 g_test_dbus_get_bus_address (GTestDBus *self)
 644 {
 645   g_return_val_if_fail (G_IS_TEST_DBUS (self), NULL);
 646
 647   return self->priv->bus_address;
 648 }
 649
 650 /**
 651  * g_test_dbus_add_service_dir:
 652  * @self: a #GTestDBus
 653  * @path: path to a directory containing .service files
 654  *
 655  * Add a path where dbus-daemon will lookup for .services files. This can't be
 656  * called after g_test_dbus_up().
 657  */
 658 void
 659 g_test_dbus_add_service_dir (GTestDBus *self,
 660     const gchar *path)
 661 {
 662   g_return_if_fail (G_IS_TEST_DBUS (self));
 663   g_return_if_fail (self->priv->bus_address == NULL);
 664
 665   g_ptr_array_add (self->priv->service_dirs, g_strdup (path));
 666 }
 667
 668 /**
 669  * g_test_dbus_up:
 670  * @self: a #GTestDBus
 671  *
 672  * Start a dbus-daemon instance and set DBUS_SESSION_BUS_ADDRESS. After this
 673  * call, it is safe for unit tests to start sending messages on the session bus.
 674  *
 675  * If this function is called from setup callback of g_test_add(),
 676  * g_test_dbus_down() must be called in its teardown callback.
 677  *
 678  * If this function is called from unit test's main(), then g_test_dbus_down()
 679  * must be called after g_test_run().
 680  */
 681 void
 682 g_test_dbus_up (GTestDBus *self)
 683 {
 684   g_return_if_fail (G_IS_TEST_DBUS (self));
 685   g_return_if_fail (self->priv->bus_address == NULL);
 686   g_return_if_fail (!self->priv->up);
 687
 688   start_daemon (self);
 689
 690   g_setenv ("DBUS_SESSION_BUS_ADDRESS", self->priv->bus_address, TRUE);
 691   self->priv->up = TRUE;
 692 }
 693
 694
 695 /**
 696  * g_test_dbus_stop:
 697  * @self: a #GTestDBus
 698  *
 699  * Stop the session bus started by g_test_dbus_up().
 700  *
 701  * Unlike g_test_dbus_down(), this won't verify the #GDBusConnection
 702  * singleton returned by g_bus_get() or g_bus_get_sync() is destroyed. Unit
 703  * tests wanting to verify behaviour after the session bus has been stopped
 704  * can use this function but should still call g_test_dbus_down() when done.
 705  */
 706 void
 707 g_test_dbus_stop (GTestDBus *self)
 708 {
 709   g_return_if_fail (G_IS_TEST_DBUS (self));
 710   g_return_if_fail (self->priv->bus_address != NULL);
 711
 712   stop_daemon (self);
 713 }
 714
 715 /**
 716  * g_test_dbus_down:
 717  * @self: a #GTestDBus
 718  *
 719  * Stop the session bus started by g_test_dbus_up().
 720  *
 721  * This will wait for the singleton returned by g_bus_get() or g_bus_get_sync()
 722  * is destroyed. This is done to ensure that the next unit test won't get a
 723  * leaked singleton from this test.
 724  */
 725 void
 726 g_test_dbus_down (GTestDBus *self)
 727 {
 728   GDBusConnection *connection;
 729
 730   g_return_if_fail (G_IS_TEST_DBUS (self));
 731   g_return_if_fail (self->priv->up);
 732
 733   connection = _g_bus_get_singleton_if_exists (G_BUS_TYPE_SESSION);
 734   if (connection != NULL)
 735     g_dbus_connection_set_exit_on_close (connection, FALSE);
 736
 737   if (self->priv->bus_address != NULL)
 738     stop_daemon (self);
 739
 740   if (connection != NULL)
 741     _g_object_unref_and_wait_weak_notify (connection);
 742
 743   g_unsetenv ("DBUS_SESSION_BUS_ADDRESS");
 744   self->priv->up = FALSE;
 745 }
 746
 747 /**
 748  * g_test_dbus_unset:
 749  *
 750  * Unset DISPLAY and DBUS_SESSION_BUS_ADDRESS env variables to ensure the test
 751  * won't use user's session bus.
 752  *
 753  * This is useful for unit tests that want to verify behaviour when no session
 754  * bus is running. It is not necessary to call this if unit test already calls
 755  * g_test_dbus_up() before acquiring the session bus.
 756  */
 757 void
 758 g_test_dbus_unset (void)
 759 {
 760   g_unsetenv ("DISPLAY");
 761   g_unsetenv ("DBUS_SESSION_BUS_ADDRESS");
 762 }