diff --git a/test_seat.c b/test_seat.c
new file mode 100644
index 0000000..ebcf1e0
--- /dev/null
+++ b/test_seat.c
@@ -0,0 +1,790 @@
+/* Wayland compositor running on top of an X server.
+
+Copyright (C) 2022 to various contributors.
+
+This file is part of 12to11.
+
+12to11 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.
+
+12to11 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 12to11.  If not, see <https://www.gnu.org/licenses/>.  */
+
+#include "12to11-test.h"
+
+/* This file is included by seat.c at the very bottom, so it does not
+   have to include anything itself! */
+
+typedef struct _TestSeatController TestSeatController;
+typedef struct _TestXIModifierState TestXIModifierState;
+typedef struct _TestXIValuatorState TestXIValuatorState;
+typedef struct _TestXIButtonState TestXIButtonState;
+
+/* The current test seat counter.  */
+static unsigned int test_seat_counter;
+
+/* The test serial counter.  */
+static unsigned long request_serial_counter;
+
+struct _TestSeatController
+{
+  /* The associated seat.  */
+  Seat *seat;
+
+  /* The associated controller resource.  */
+  struct wl_resource *resource;
+};
+
+struct _TestXIModifierState
+{
+  /* Modifier state.  These fields mean the same as they do in
+     XIModifierState.  */
+  int base;
+  int latched;
+  int locked;
+  int effective;
+};
+
+struct _TestXIValuatorState
+{
+  /* The mask of set valuators.  */
+  unsigned char *mask;
+
+  /* Sparse array of valuators.  */
+  double *values;
+
+  /* The length of the mask.  */
+  size_t mask_len;
+
+  /* The number of valuators set.  */
+  int num_valuators;
+};
+
+struct _TestXIButtonState
+{
+  /* Mask of set buttons.  Always between 0 and 8.  */
+  unsigned char mask[XIMaskLen (8)];
+};
+
+
+
+static void
+DestroyXIModifierState (struct wl_client *client,
+			struct wl_resource *resource)
+{
+  wl_resource_destroy (resource);
+}
+
+static void
+SetValues (struct wl_client *client, struct wl_resource *resource,
+	   int32_t base, int32_t latched, int32_t locked, int32_t effective)
+{
+  TestXIModifierState *state;
+
+  state = wl_resource_get_user_data (resource);
+  state->base = base;
+  state->latched = latched;
+  state->locked = locked;
+  state->effective = effective;
+}
+
+static const struct test_XIModifierState_interface XIModifierState_impl =
+  {
+    .destroy = DestroyXIModifierState,
+    .set_values = SetValues,
+  };
+
+static void
+HandleXIModifierStateDestroy (struct wl_resource *resource)
+{
+  TestXIModifierState *state;
+
+  state = wl_resource_get_user_data (resource);
+  XLFree (state);
+}
+
+
+
+static void
+DestroyXIButtonState (struct wl_client *client,
+		      struct wl_resource *resource)
+{
+  wl_resource_destroy (resource);
+}
+
+static void
+AddButton (struct wl_client *client, struct wl_resource *resource,
+	   uint32_t button)
+{
+  TestXIButtonState *state;
+
+  state = wl_resource_get_user_data (resource);
+
+  if (button < 1 || button > 8)
+    /* The button is invalid.  */
+    wl_resource_post_error (resource, TEST_MANAGER_ERROR_INVALID_BUTTON,
+			    "invalid button specified");
+  else
+    SetMask (state->mask, button);
+}
+
+static void
+RemoveButton (struct wl_client *client, struct wl_resource *resource,
+	      uint32_t button)
+{
+  TestXIButtonState *state;
+
+  state = wl_resource_get_user_data (resource);
+
+  if (button < 1 || button > 8)
+    wl_resource_post_error (resource, TEST_MANAGER_ERROR_INVALID_BUTTON,
+			    "invalid button specified");
+  else
+    ClearMask (state->mask, button);
+}
+
+static const struct test_XIButtonState_interface XIButtonState_impl =
+  {
+    .destroy = DestroyXIButtonState,
+    .add_button = AddButton,
+    .remove_button = RemoveButton,
+  };
+
+static void
+HandleXIButtonStateDestroy (struct wl_resource *resource)
+{
+  TestXIButtonState *state;
+
+  state = wl_resource_get_user_data (resource);
+  XLFree (state);
+}
+
+
+
+static void
+AddValuatorToTestXIValuatorState (struct wl_client *client,
+				  struct wl_resource *resource,
+				  uint32_t valuator,
+				  wl_fixed_t value)
+{
+  TestXIValuatorState *state;
+  double *old_values, *new_values;
+  size_t i, j;
+
+  if (valuator < 1 || valuator > 65535)
+    {
+      /* The valuator cannot be represented.  */
+      wl_resource_post_error (resource, TEST_MANAGER_ERROR_INVALID_VALUATOR,
+			      "the specified valuator cannot be represented");
+      return;
+    }
+
+  state = wl_resource_get_user_data (resource);
+
+  /* Check if the valuator is already present and post a
+     value_exists error if so.  */
+  if (XIMaskLen (valuator) <= state->mask_len
+      && MaskIsSet (state->mask, valuator))
+    wl_resource_post_error (resource, TEST_MANAGER_ERROR_VALUE_EXISTS,
+			    "the specified valuator is already set");
+  else
+    {
+      /* If the mask needs to be expanded, do it now.  */
+      if (state->mask_len < XIMaskLen (valuator))
+	{
+	  state->mask = XLRealloc (state->mask,
+				   state->mask_len);
+
+	  /* Clear the newly allocated part of the mask.  */
+	  memset (state->mask + state->mask_len,
+		  0, XIMaskLen (valuator) - state->mask_len);
+	}
+
+      SetMask (state->mask, valuator);
+      state->num_valuators++;
+
+      /* Now, rewrite the sparse array of values.  */
+      old_values = state->values;
+      new_values = XLCalloc (state->num_valuators,
+			     sizeof *state->values);
+
+      for (i = 0, j = 0; i < MAX (state->mask_len,
+				  XIMaskLen (valuator)) * 8; ++i)
+	{
+	  if (i == valuator)
+	    /* Insert the new value.  */
+	    new_values[j++] = wl_fixed_to_double (value);
+	  else if (XIMaskIsSet (state->mask, valuator))
+	    /* Use the old value.  */
+	    new_values[j++] = *old_values++;
+	}
+
+      /* Free the old values.  */
+      XLFree (state->values);
+
+      /* Assign the new values and mask length to the state.  */
+      state->values = new_values;
+      state->mask_len = MAX (state->mask_len,
+			     XIMaskLen (valuator));
+    }
+}
+
+static const struct test_XIValuatorState_interface XIValuatorState_impl =
+  {
+    .add_valuator = AddValuatorToTestXIValuatorState,
+  };
+
+static void
+HandleXIValuatorStateDestroy (struct wl_resource *resource)
+{
+  TestXIValuatorState *state;
+
+  state = wl_resource_get_user_data (resource);
+
+  /* Free the mask.  */
+  XLFree (state->mask);
+
+  /* Free the values.  */
+  XLFree (state->values);
+
+  /* Free the state itself.  */
+  XLFree (state);
+}
+
+
+
+static void
+DestroyTestSeatController (struct wl_client *client,
+			   struct wl_resource *resource)
+{
+  wl_resource_destroy (resource);
+}
+
+static void
+BindSeat (struct wl_client *client, struct wl_resource *resource,
+	  uint32_t version, uint32_t id)
+{
+  TestSeatController *controller;
+
+  controller = wl_resource_get_user_data (resource);
+
+  if (!version || version > 8)
+    wl_resource_post_error (resource, TEST_MANAGER_ERROR_BAD_SEAT_VERSION,
+			    "the specified version of the wl_seat interface"
+			    " is not supported");
+  else
+    /* Bind the resource to the seat.  */
+    HandleBind1 (client, controller->seat, version, id);
+}
+
+static void
+GetXIModifierState (struct wl_client *client, struct wl_resource *resource,
+		    uint32_t id)
+{
+  TestXIModifierState *state;
+  struct wl_resource *state_resource;
+
+  state = XLSafeMalloc (sizeof *state);
+
+  if (!state)
+    {
+      /* Allocating the state structure failed.  */
+      wl_resource_post_no_memory (resource);
+      return;
+    }
+
+  /* Now, try to create the modifier state resource.  */
+  state_resource
+    = wl_resource_create (client, &test_XIModifierState_interface,
+			  wl_resource_get_version (resource), id);
+
+  if (!state_resource)
+    {
+      /* Allocating the resource failed.  */
+      XLFree (state);
+      wl_resource_post_no_memory (resource);
+
+      return;
+    }
+
+  /* Clear the state.  */
+  memset (state, 0, sizeof *state);
+
+  /* Set the resource data.  */
+  wl_resource_set_implementation (state_resource, &XIModifierState_impl,
+				  state, HandleXIModifierStateDestroy);
+}
+
+static void
+GetXIButtonState (struct wl_client *client, struct wl_resource *resource,
+		  uint32_t id)
+{
+  TestXIButtonState *state;
+  struct wl_resource *state_resource;
+
+  state = XLSafeMalloc (sizeof *state);
+
+  if (!state)
+    {
+      /* Allocating the state structure failed.  */
+      wl_resource_post_no_memory (resource);
+      return;
+    }
+
+  /* Now, try to create the button state resource.  */
+  state_resource
+    = wl_resource_create (client, &test_XIButtonState_interface,
+			  wl_resource_get_version (resource), id);
+
+  if (!state_resource)
+    {
+      /* Allocating the resource failed.  */
+      XLFree (state);
+      wl_resource_post_no_memory (resource);
+
+      return;
+    }
+
+  /* Clear the state.  */
+  memset (state, 0, sizeof *state);
+
+  /* Set the resource data.  */
+  wl_resource_set_implementation (state_resource, &XIButtonState_impl,
+				  state, HandleXIButtonStateDestroy);
+}
+
+static void
+GetXIValuatorState (struct wl_client *client, struct wl_resource *resource,
+		    uint32_t id)
+{
+  TestXIValuatorState *state;
+  struct wl_resource *state_resource;
+
+  state = XLSafeMalloc (sizeof *state);
+
+  if (!state)
+    {
+      /* Allocating the state structure failed.  */
+      wl_resource_post_no_memory (resource);
+      return;
+    }
+
+  /* Now, try to create the button state resource.  */
+  state_resource
+    = wl_resource_create (client, &test_XIValuatorState_interface,
+			  wl_resource_get_version (resource), id);
+
+  if (!state_resource)
+    {
+      /* Allocating the resource failed.  */
+      XLFree (state);
+      wl_resource_post_no_memory (resource);
+
+      return;
+    }
+
+  /* Clear the state.  */
+  memset (state, 0, sizeof *state);
+
+  /* Set the resource data.  */
+  wl_resource_set_implementation (state_resource, &XIValuatorState_impl,
+				  state, HandleXIValuatorStateDestroy);
+}
+
+
+
+static void
+TranslateTestButtons (struct wl_resource *resource, XIButtonState *buttons)
+{
+  TestXIButtonState *state;
+
+  if (!resource)
+    {
+      /* Use default values if nothing was specified.  */
+
+      buttons->mask_len = 0;
+      buttons->mask = NULL;
+
+      return;
+    }
+
+  /* The mask in buttons will be destroyed along with the resource! */
+  state = wl_resource_get_user_data (resource);
+  buttons->mask_len = sizeof state->mask;
+  buttons->mask = state->mask;
+}
+
+static void
+TranslateTestValuators (struct wl_resource *resource,
+			XIValuatorState *valuators)
+{
+  TestXIValuatorState *state;
+
+  if (!resource)
+    {
+      /* Use default values if nothing was specified.  */
+      valuators->mask_len = 0;
+      valuators->values = NULL;
+      valuators->mask = NULL;
+
+      return;
+    }
+
+  state = wl_resource_get_user_data (resource);
+  valuators->mask_len = state->mask_len;
+  valuators->mask = state->mask;
+  valuators->values = state->values;
+}
+
+static void
+TranslateTestModifiers (struct wl_resource *resource,
+			XIModifierState *modifiers)
+{
+  TestXIModifierState *state;
+
+  if (!resource)
+    {
+      /* Use default values if nothing was specified.  */
+      modifiers->base = 0;
+      modifiers->latched = 0;
+      modifiers->locked = 0;
+      modifiers->effective = 0;
+
+      return;
+    }
+
+  state = wl_resource_get_user_data (resource);
+  modifiers->base = state->base;
+  modifiers->latched = state->latched;
+  modifiers->locked = state->locked;
+  modifiers->effective = state->effective;
+}
+
+static void
+DispatchTestEvent (TestSeatController *controller, Window window,
+		   XIEvent *event)
+{
+  Surface *surface;
+  Subcompositor *subcompositor;
+
+  /* Look up a test surface with the given window and dispatch the
+     event to it.  */
+
+  surface = XLLookUpTestSurface (window, &subcompositor);
+
+  if (!surface)
+    /* The client submitted an invalid event window! */
+    return;
+
+  if (event->evtype == XI_FocusIn)
+    DispatchFocusIn (surface, (XIFocusInEvent *) event);
+  else if (event->evtype == XI_FocusOut)
+    DispatchFocusOut (surface, (XIFocusOutEvent *) event);
+  else if (event->evtype == XI_Enter
+	   || event->evtype == XI_Leave)
+    DispatchEntryExit (subcompositor, (XIEnterEvent *) event);
+  else if (event->evtype == XI_Motion)
+    DispatchMotion (subcompositor, (XIDeviceEvent *) event);
+  else if (event->evtype == XI_ButtonPress
+	   || event->evtype == XI_ButtonRelease)
+    DispatchButton (subcompositor, (XIDeviceEvent *) event);
+  else if (event->evtype == XI_KeyPress
+	   || event->evtype == XI_KeyRelease)
+    DispatchKey ((XIDeviceEvent *) event);
+  else if (event->evtype == XI_BarrierHit)
+    DispatchBarrierHit ((XIBarrierEvent *) event);
+  else if (event->evtype == XI_GesturePinchBegin
+	   || event->evtype == XI_GesturePinchUpdate
+	   || event->evtype == XI_GesturePinchEnd)
+    DispatchGesturePinch (subcompositor, (XIGesturePinchEvent *) event);
+  else if (event->evtype == XI_GestureSwipeBegin
+	   || event->evtype == XI_GestureSwipeUpdate
+	   || event->evtype == XI_GestureSwipeEnd)
+    DispatchGestureSwipe (subcompositor, (XIGestureSwipeEvent *) event);
+}
+
+#define GenerateCrossingEvent(event_type, controller, test_event)	\
+  test_event.type = GenericEvent;					\
+  test_event.serial = request_serial_counter++;				\
+  test_event.send_event = True;						\
+  test_event.display = compositor.display;				\
+  test_event.extension = xi2_opcode;					\
+  test_event.evtype = event_type;					\
+  test_event.time = time;						\
+  test_event.deviceid = controller->seat->master_pointer;		\
+  test_event.sourceid = sourceid;					\
+  test_event.detail = detail;						\
+  test_event.root = root;						\
+  test_event.event = event;						\
+  test_event.child = child;						\
+  test_event.root_x = wl_fixed_to_double (root_x);			\
+  test_event.root_y = wl_fixed_to_double (root_y);			\
+  test_event.event_x = wl_fixed_to_double (event_x);			\
+  test_event.event_y = wl_fixed_to_double (event_y);			\
+  test_event.mode = mode;						\
+  test_event.focus = focus;						\
+  test_event.same_screen = same_screen;					\
+  TranslateTestButtons (buttons_resource, &test_event.buttons);		\
+  TranslateTestModifiers (mods_resource, &test_event.mods);		\
+  TranslateTestModifiers (group_resource, &test_event.group)
+
+static void
+DispatchXIEnter (struct wl_client *client, struct wl_resource *resource,
+		 uint32_t time, int32_t sourceid, int32_t detail,
+		 uint32_t root, uint32_t event, uint32_t child,
+		 wl_fixed_t root_x, wl_fixed_t root_y,
+		 wl_fixed_t event_x, wl_fixed_t event_y, int32_t mode,
+		 int32_t focus, int32_t same_screen,
+		 struct wl_resource *buttons_resource,
+		 struct wl_resource *mods_resource,
+		 struct wl_resource *group_resource)
+{
+  TestSeatController *controller;
+  XIEnterEvent test_event;
+
+  controller = wl_resource_get_user_data (resource);
+  GenerateCrossingEvent (XI_Enter, controller, test_event);
+
+  /* Now dispatch the event.  */
+  DispatchTestEvent (controller, event, (XIEvent *) &test_event);
+}
+
+static void
+DispatchXILeave (struct wl_client *client, struct wl_resource *resource,
+		 uint32_t time, int32_t sourceid, int32_t detail,
+		 uint32_t root, uint32_t event, uint32_t child,
+		 wl_fixed_t root_x, wl_fixed_t root_y,
+		 wl_fixed_t event_x, wl_fixed_t event_y, int32_t mode,
+		 int32_t focus, int32_t same_screen,
+		 struct wl_resource *buttons_resource,
+		 struct wl_resource *mods_resource,
+		 struct wl_resource *group_resource)
+{
+  TestSeatController *controller;
+  XILeaveEvent test_event;
+
+  controller = wl_resource_get_user_data (resource);
+  GenerateCrossingEvent (XI_Leave, controller, test_event);
+
+  /* Now dispatch the event.  */
+  DispatchTestEvent (controller, event, (XIEvent *) &test_event);
+}
+
+#define GenerateDeviceEvent(event_type, controller, test_event)		\
+  test_event.type = GenericEvent;					\
+  test_event.serial = request_serial_counter++;				\
+  test_event.send_event = True;						\
+  test_event.display = compositor.display;				\
+  test_event.extension = xi2_opcode;					\
+  test_event.evtype = event_type;					\
+  test_event.time = time;						\
+  test_event.deviceid = controller->seat->master_pointer;		\
+  test_event.sourceid = sourceid;					\
+  test_event.detail = detail;						\
+  test_event.root = root;						\
+  test_event.child = child;						\
+  test_event.event = event;						\
+  test_event.root_x = wl_fixed_to_double (root_x);			\
+  test_event.root_y = wl_fixed_to_double (root_y);			\
+  test_event.event_x = wl_fixed_to_double (event_x);			\
+  test_event.event_y = wl_fixed_to_double (event_y);			\
+  test_event.flags = flags;						\
+  TranslateTestButtons (buttons_resource, &test_event.buttons);		\
+  TranslateTestValuators (valuators_resource, &test_event.valuators);	\
+  TranslateTestModifiers (mods_resource, &test_event.mods);		\
+  TranslateTestModifiers (group_resource, &test_event.group)
+
+static void
+DispatchXIMotion (struct wl_client *client, struct wl_resource *resource,
+		  uint32_t time, int32_t sourceid, int32_t detail,
+		  uint32_t root, uint32_t event, uint32_t child,
+		  wl_fixed_t root_x, wl_fixed_t root_y, wl_fixed_t event_x,
+		  wl_fixed_t event_y, int32_t flags,
+		  struct wl_resource *buttons_resource,
+		  struct wl_resource *valuators_resource,
+		  struct wl_resource *mods_resource,
+		  struct wl_resource *group_resource)
+{
+  TestSeatController *controller;
+  XIDeviceEvent test_event;
+
+  controller = wl_resource_get_user_data (resource);
+  GenerateDeviceEvent (XI_Motion, controller, test_event);
+
+  /* Now dispatch the event.  */
+  DispatchTestEvent (controller, event, (XIEvent *) &test_event);
+}
+
+static void
+DispatchXIButtonPress (struct wl_client *client, struct wl_resource *resource,
+		       uint32_t time, int32_t sourceid, int32_t detail,
+		       uint32_t root, uint32_t event, uint32_t child,
+		       wl_fixed_t root_x, wl_fixed_t root_y,
+		       wl_fixed_t event_x, wl_fixed_t event_y, int32_t flags,
+		       struct wl_resource *buttons_resource,
+		       struct wl_resource *valuators_resource,
+		       struct wl_resource *mods_resource,
+		       struct wl_resource *group_resource)
+{
+  TestSeatController *controller;
+  XIDeviceEvent test_event;
+
+  controller = wl_resource_get_user_data (resource);
+  GenerateDeviceEvent (XI_ButtonPress, controller, test_event);
+
+  /* Now dispatch the event.  */
+  DispatchTestEvent (controller, event, (XIEvent *) &test_event);
+}
+
+static void
+DispatchXIButtonRelease (struct wl_client *client, struct wl_resource *resource,
+			 uint32_t time, int32_t sourceid, int32_t detail,
+			 uint32_t root, uint32_t event, uint32_t child,
+			 wl_fixed_t root_x, wl_fixed_t root_y,
+			 wl_fixed_t event_x, wl_fixed_t event_y, int32_t flags,
+			 struct wl_resource *buttons_resource,
+			 struct wl_resource *valuators_resource,
+			 struct wl_resource *mods_resource,
+			 struct wl_resource *group_resource)
+{
+  TestSeatController *controller;
+  XIDeviceEvent test_event;
+
+  controller = wl_resource_get_user_data (resource);
+  GenerateDeviceEvent (XI_ButtonRelease, controller, test_event);
+
+  /* Now dispatch the event.  */
+  DispatchTestEvent (controller, event, (XIEvent *) &test_event);
+}
+
+static const struct test_seat_controller_interface seat_controller_impl =
+  {
+    .destroy = DestroyTestSeatController,
+    .bind_seat = BindSeat,
+    .get_XIModifierState = GetXIModifierState,
+    .get_XIButtonState = GetXIButtonState,
+    .get_XIValuatorState = GetXIValuatorState,
+    .dispatch_XI_Enter = DispatchXIEnter,
+    .dispatch_XI_Leave = DispatchXILeave,
+    .dispatch_XI_Motion = DispatchXIMotion,
+    .dispatch_XI_ButtonPress = DispatchXIButtonPress,
+    .dispatch_XI_ButtonRelease = DispatchXIButtonRelease,
+  };
+
+static void
+HandleControllerResourceDestroy (struct wl_resource *resource)
+{
+  TestSeatController *controller;
+  Seat *seat;
+
+  controller = wl_resource_get_user_data (resource);
+  seat = controller->seat;
+
+  /* Make the seat inert and remove it from live_seats.  */
+  seat->flags |= IsInert;
+
+  /* Set the focus surface to NULL, so surfaces don't mistakenly
+     treat themselves as still focused.  */
+
+  SetFocusSurface (seat, NULL);
+
+  /* Run destroy handlers.  */
+
+  RunDestroyListeners (seat);
+
+  /* Since the seat is now inert, remove it from the assoc
+     table and destroy the global.  */
+
+  XLDeleteAssoc (seats, seat->master_keyboard);
+  XLDeleteAssoc (seats, seat->master_pointer);
+
+  /* Also remove it from the list of live seats.  */
+
+  live_seats = XLListRemove (live_seats, seat);
+
+  /* Run and remove all resize completion callbacks.  */
+
+  RunResizeDoneCallbacks (seat);
+
+  /* And release the seat.  */
+
+  ReleaseSeat (seat);
+
+  /* Free the controller resource.  */
+  XLFree (controller);
+}
+
+
+
+void
+XLGetTestSeat (struct wl_client *client, struct wl_resource *resource,
+	       uint32_t id)
+{
+  TestSeatController *controller;
+  Seat *seat;
+  char name_format[sizeof "test seat: " + 40];
+
+  controller = XLSafeMalloc (sizeof *controller);
+
+  if (!controller)
+    {
+      wl_resource_post_no_memory (resource);
+      return;
+    }
+
+  memset (controller, 0, sizeof *controller);
+  controller->resource
+    = wl_resource_create (client, &test_seat_controller_interface,
+			  wl_resource_get_version (resource), id);
+
+  if (!controller->resource)
+    {
+      wl_resource_post_no_memory (resource);
+      XLFree (controller);
+      return;
+    }
+
+  seat = XLCalloc (1, sizeof *seat);
+
+  /* Allocate a "device ID" for the seat.  Device IDs are unsigned 16
+     bit values, so any larger value is guaranteed to be okay for our
+     own use.  */
+
+  if (!test_seat_counter)
+    test_seat_counter = 65555;
+  test_seat_counter++;
+
+  /* Initialize some random bogus values.  */
+  seat->master_pointer = test_seat_counter;
+  seat->master_keyboard = test_seat_counter;
+
+  /* Add a unique seat name.  */
+  sprintf (name_format, "test seat %u", test_seat_counter);
+  seat->name = XLStrdup (name_format);
+
+  /* Refrain from creating a global for this seat.  */
+  seat->global = NULL;
+
+  InitSeatCommon (seat);
+
+  /* Associate the dummy device with the seat.  */
+  XLMakeAssoc (seats, test_seat_counter, seat);
+  seat->flags |= IsTestSeat;
+
+  /* Add the seat to the live seat list.  */
+  live_seats = XLListPrepend (live_seats, seat);
+
+  /* Retain the seat.  */
+  RetainSeat (seat);
+  controller->seat = seat;
+
+  wl_resource_set_implementation (controller->resource, &seat_controller_impl,
+				  controller, HandleControllerResourceDestroy);
+}
diff --git a/tests/seat_test.c b/tests/seat_test.c
new file mode 100644
index 0000000..5a74081
--- /dev/null
+++ b/tests/seat_test.c
@@ -0,0 +1,480 @@
+/* Tests for the Wayland compositor running on the X server.
+
+Copyright (C) 2022 to various contributors.
+
+This file is part of 12to11.
+
+12to11 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.
+
+12to11 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 12to11.  If not, see <https://www.gnu.org/licenses/>.  */
+
+#include "test_harness.h"
+
+#include <X11/extensions/XI2.h>
+
+enum test_expect_event_kind
+  {
+    POINTER_ENTER_EVENT,
+    POINTER_FRAME_EVENT,
+    POINTER_MOTION_EVENT,
+  };
+
+struct test_expect_data
+{
+  /* The coordinates of the event.  */
+  double x, y;
+
+  /* What kind of event is being waited for.  */
+  enum test_expect_event_kind kind;
+
+  /* Whether or not the expected event arrived.  */
+  bool arrived;
+};
+
+enum test_kind
+  {
+    MAP_WINDOW_KIND,
+    TEST_ENTRY_KIND,
+  };
+
+static const char *test_names[] =
+  {
+    "map_window",
+    "test_entry",
+  };
+
+#define LAST_TEST	        TEST_ENTRY_KIND
+#define TEST_SOURCE_DEVICE	4500000
+
+/* The display.  */
+static struct test_display *display;
+
+/* Test interfaces.  */
+static struct test_interface test_interfaces[] =
+  {
+    /* No interfaces yet.  */
+  };
+
+/* The test surface window.  */
+static Window test_surface_window;
+
+/* The test surface and Wayland surface.  */
+static struct test_surface *test_surface;
+static struct wl_surface *wayland_surface;
+
+/* How many elements are in the current listener data.  */
+static int num_listener_data;
+
+/* The current listener data.  */
+struct test_expect_data *current_listener_data;
+
+
+
+/* Forward declarations.  */
+static void submit_surface_damage (struct wl_surface *, int, int, int, int);
+static void expect_surface_enter (double, double);
+static void expect_surface_motion (double, double);
+
+
+
+/* Get a timestamp suitable for use in events dispatched to the test
+   seat.  */
+
+static uint32_t
+test_get_time (void)
+{
+  struct timespec timespec;
+
+  clock_gettime (CLOCK_MONOTONIC, &timespec);
+
+  return (timespec.tv_sec * 1000
+	  + timespec.tv_nsec / 1000000);
+}
+
+/* Get the root window.  */
+
+static Window
+test_get_root (void)
+{
+  return DefaultRootWindow (display->x_display);
+}
+
+
+
+static void
+test_single_step (enum test_kind kind)
+{
+  struct wl_buffer *buffer;
+
+  test_log ("running test step: %s", test_names[kind]);
+
+  switch (kind)
+    {
+    case MAP_WINDOW_KIND:
+      buffer = load_png_image (display, "seat_test.png");
+
+      if (!buffer)
+	report_test_failure ("failed to load seat_test.png");
+
+      wl_surface_attach (wayland_surface, buffer, 0, 0);
+      submit_surface_damage (wayland_surface, 0, 0, 500, 500);
+      wl_surface_commit (wayland_surface);
+      wl_buffer_destroy (buffer);
+      break;
+
+    case TEST_ENTRY_KIND:
+      /* Enter the 500x500 window.  The window is at 0, 0 relative to
+	 the root window.  */
+      test_seat_controller_dispatch_XI_Enter (display->seat->controller,
+					      test_get_time (),
+					      TEST_SOURCE_DEVICE,
+					      XINotifyAncestor,
+					      test_get_root (),
+					      test_surface_window,
+					      None,
+					      wl_fixed_from_double (0.0),
+					      wl_fixed_from_double (0.0),
+					      wl_fixed_from_double (0.0),
+					      wl_fixed_from_double (0.0),
+					      XINotifyNormal,
+					      False, True, NULL, NULL,
+					      NULL);
+
+      /* Expect an enter at 0.0 by 0.0.  */
+      expect_surface_enter (0.0, 0.0);
+
+      /* Now move the mouse a little.  */
+      test_seat_controller_dispatch_XI_Motion (display->seat->controller,
+					       test_get_time (),
+					       TEST_SOURCE_DEVICE,
+					       0,
+					       test_get_root (),
+					       test_surface_window,
+					       None,
+					       wl_fixed_from_double (1.0),
+					       wl_fixed_from_double (2.0),
+					       wl_fixed_from_double (1.0),
+					       wl_fixed_from_double (2.0),
+					       0,
+					       NULL, NULL, NULL, NULL);
+
+      /* Expect mouse motion at the specified coordinates.  */
+      expect_surface_motion (1.0, 2.0);
+      break;
+    }
+
+  if (kind == LAST_TEST)
+    test_complete ();
+}
+
+
+
+static void
+expect_surface_enter (double x, double y)
+{
+  struct test_expect_data data[2];
+
+  test_log ("waiting for enter at %g, %g", x, y);
+
+  memset (data, 0, sizeof data);
+
+  data[0].x = x;
+  data[0].y = y;
+  data[0].kind = POINTER_ENTER_EVENT;
+  data[1].kind = POINTER_FRAME_EVENT;
+
+  /* Set the current listener data and do a roundtrip.  */
+  current_listener_data = data;
+  num_listener_data = 2;
+
+  wl_display_roundtrip (display->display);
+  current_listener_data = NULL;
+  num_listener_data = 0;
+
+  /* See whether or not the event arrived.  */
+  if (!data[0].arrived || !data[1].arrived)
+    report_test_failure ("expected events did not arrive");
+  else
+    test_log ("received enter followed by frame");
+}
+
+static void
+expect_surface_motion (double x, double y)
+{
+  struct test_expect_data data[2];
+
+  test_log ("waiting for motion at %g, %g", x, y);
+
+  memset (data, 0, sizeof data);
+
+  data[0].x = x;
+  data[0].y = y;
+  data[0].kind = POINTER_MOTION_EVENT;
+  data[1].kind = POINTER_FRAME_EVENT;
+
+  /* Set the current listener data and do a roundtrip.  */
+  current_listener_data = data;
+  num_listener_data = 2;
+
+  wl_display_roundtrip (display->display);
+  current_listener_data = NULL;
+  num_listener_data = 0;
+
+  /* See whether or not the event arrived.  */
+  if (!data[0].arrived || !data[1].arrived)
+    report_test_failure ("expected events did not arrive");
+  else
+    test_log ("received motion followed by frame");
+}
+
+
+
+static void
+handle_test_surface_mapped (void *data, struct test_surface *surface,
+			    uint32_t xid, const char *display_string)
+{
+  /* Sleep for 1 second to ensure that the window is exposed and
+     redirected.  */
+  sleep (1);
+
+  /* Start the test.  */
+  test_surface_window = xid;
+
+  /* Run the test again.  */
+  test_single_step (TEST_ENTRY_KIND);
+}
+
+static const struct test_surface_listener test_surface_listener =
+  {
+    handle_test_surface_mapped,
+  };
+
+
+
+/* Obtain the next test data record.  The events arriving are checked
+   to be in the order in which they arrive in
+   current_listener_data.  */
+
+static struct test_expect_data *
+get_next_expect_data (void)
+{
+  struct test_expect_data *data;
+  int i;
+
+  data = current_listener_data;
+
+  for (i = 0; i < num_listener_data; ++i)
+    {
+      if (current_listener_data[i].arrived)
+	continue;
+
+      return &current_listener_data[i];
+    }
+
+  return NULL;
+}
+
+static void
+handle_pointer_enter (void *data, struct wl_pointer *wl_pointer,
+		      uint32_t serial, struct wl_surface *surface,
+		      wl_fixed_t surface_x, wl_fixed_t surface_y)
+{
+  struct test_expect_data *test_data;
+
+  test_data = get_next_expect_data ();
+
+  if (!test_data)
+    {
+      test_log ("ignored enter event at %g %g",
+		wl_fixed_to_double (surface_x),
+		wl_fixed_to_double (surface_y));
+      return;
+    }
+
+  if (test_data->kind != POINTER_ENTER_EVENT)
+    return;
+
+  test_log ("got enter event at %g, %g",
+	    wl_fixed_to_double (surface_x),
+	    wl_fixed_to_double (surface_y));
+
+  if (test_data->x == wl_fixed_to_double (surface_x)
+      && test_data->y == wl_fixed_to_double (surface_y))
+    test_data->arrived = true;
+  else
+    report_test_failure ("missed enter event at %g %g",
+			 test_data->x, test_data->y);
+}
+
+static void
+handle_pointer_leave (void *data, struct wl_pointer *wl_pointer,
+		      uint32_t serial, struct wl_surface *surface)
+{
+  /* ... */
+}
+
+static void
+handle_pointer_motion (void *data, struct wl_pointer *wl_pointer,
+		       uint32_t time, wl_fixed_t surface_x,
+		       wl_fixed_t surface_y)
+{
+  struct test_expect_data *test_data;
+
+  test_data = get_next_expect_data ();
+
+  if (!test_data)
+    {
+      test_log ("ignored motion event at %g %g",
+		wl_fixed_to_double (surface_x),
+		wl_fixed_to_double (surface_y));
+      return;
+    }
+
+  if (test_data->kind != POINTER_MOTION_EVENT)
+    return;
+
+  test_log ("got motion event at %g, %g",
+	    wl_fixed_to_double (surface_x),
+	    wl_fixed_to_double (surface_y));
+
+  if (test_data->x == wl_fixed_to_double (surface_x)
+      && test_data->y == wl_fixed_to_double (surface_y))
+    test_data->arrived = true;
+  else
+    report_test_failure ("missed motion event at %g %g",
+			 test_data->x, test_data->y);
+}
+
+static void
+handle_pointer_button (void *data, struct wl_pointer *wl_pointer,
+		       uint32_t serial, uint32_t time, uint32_t button,
+		       uint32_t state)
+{
+  /* TODO... */
+}
+
+static void
+handle_pointer_axis (void *data, struct wl_pointer *wl_pointer,
+		     uint32_t time, uint32_t axis, wl_fixed_t value)
+{
+  /* TODO... */
+}
+
+static void
+handle_pointer_frame (void *data, struct wl_pointer *wl_pointer)
+{
+  struct test_expect_data *test_data;
+
+  test_data = get_next_expect_data ();
+
+  if (!test_data)
+    {
+      test_log ("ignored frame event");
+      return;
+    }
+
+  if (test_data->kind != POINTER_FRAME_EVENT)
+    return;
+
+  test_log ("got frame event");
+  test_data->arrived = true;
+}
+
+static void
+handle_pointer_axis_source (void *data, struct wl_pointer *wl_pointer,
+			    uint32_t axis_source)
+{
+  /* TODO... */
+}
+
+static void
+handle_pointer_axis_stop (void *data, struct wl_pointer *wl_pointer,
+			  uint32_t time, uint32_t axis)
+{
+  /* TODO... */
+}
+
+static void
+handle_pointer_axis_discrete (void *data, struct wl_pointer *wl_pointer,
+			      uint32_t axis, int32_t discrete)
+{
+  /* TODO... */
+}
+
+static void
+handle_pointer_axis_value120 (void *data, struct wl_pointer *wl_pointer,
+			      uint32_t axis, int32_t value120)
+{
+  /* TODO... */
+}
+
+static const struct wl_pointer_listener pointer_listener =
+  {
+    handle_pointer_enter,
+    handle_pointer_leave,
+    handle_pointer_motion,
+    handle_pointer_button,
+    handle_pointer_axis,
+    handle_pointer_frame,
+    handle_pointer_axis_source,
+    handle_pointer_axis_stop,
+    handle_pointer_axis_discrete,
+    handle_pointer_axis_value120,
+  };
+
+
+
+static void
+submit_surface_damage (struct wl_surface *surface, int x, int y, int width,
+		       int height)
+{
+  test_log ("damaging surface by %d, %d, %d, %d", x, y, width,
+	    height);
+
+  wl_surface_damage (surface, x, y, width, height);
+}
+
+static void
+run_test (void)
+{
+  if (!make_test_surface (display, &wayland_surface,
+			  &test_surface))
+    report_test_failure ("failed to create test surface");
+
+  test_surface_add_listener (test_surface, &test_surface_listener,
+			     NULL);
+  test_single_step (MAP_WINDOW_KIND);
+
+  /* Initialize the pointer listener.  */
+  wl_pointer_add_listener (display->seat->pointer, &pointer_listener,
+			   NULL);
+
+  while (true)
+    {
+      if (wl_display_dispatch (display->display) == -1)
+        die ("wl_display_dispatch");
+    }
+}
+
+int
+main (void)
+{
+  test_init ();
+  display = open_test_display (test_interfaces,
+			       ARRAYELTS (test_interfaces));
+
+  if (!display)
+    report_test_failure ("failed to open display");
+
+  test_init_seat (display);
+  run_test ();
+}
diff --git a/tests/seat_test.png b/tests/seat_test.png
new file mode 100644
index 0000000..ce46f94
Binary files /dev/null and b/tests/seat_test.png differ