uitests: Handle slow app launch on fedora 39

Not quite sure what's going on here, I think it has something to
do with slowness when the accessibility bus is being polled.

Add some infrastructure to increase the timeout while we wait for
the app to pop up

Signed-off-by: Cole Robinson <crobinso@redhat.com>

tests/uitests/lib/app.py

@@ -347,6 +347,11 @@ class VMMDogtailApp(object):
         if check_already_running:
             self.error_if_already_running()
         self._proc = subprocess.Popen(cmd, stdout=stdout, stderr=stderr)
-        if not will_fail:
+        if will_fail:
+            return
+
+        with utils.dogtail_timeout(10):
+            # On Fedora 39 sometimes app launch from the test suite
+            # takes a while for reasons I can't quite figure
             self._root = dogtail.tree.root.application("virt-manager")
             self._topwin = self.find_window(window_name)

tests/uitests/lib/utils.py

@@ -3,6 +3,8 @@
 
 import time
 
+import dogtail.config
+
 
 def check(func, timeout=2):
     """
@@ -19,6 +21,26 @@ def check(func, timeout=2):
         time.sleep(interval)
 
 
+class dogtail_timeout:
+    """
+    Context helper to run a specific check with custom timeout, in seconds
+    """
+    def __init__(self, timeout):
+        backoff = dogtail.config.config.searchBackoffDuration
+        self._tmpval = int(timeout / backoff)
+        self._origval = dogtail.config.config.searchCutoffCount
+
+    def _set(self, val):
+        dogtail.config.config.searchCutoffCount = val
+
+    def __enter__(self):
+        self._set(self._tmpval)
+        return self
+
+    def __exit__(self, exc_type, exc_val, exc_tb):
+        self._set(self._origval)
+
+
 def walkUIList(app, win, lst, error_cb, reverse=False):
     """
     Toggle down through a UI list like addhardware, net/storage/iface