If this is the only failing test - most likely no, the test is probably not reliable enough. Does it still fail if you build in a clean chroot (extra-x86_64-build)?

Could you please create a bug report in https://github.com/ddterm/gnome-shell-extension-ddterm, with full log (build/meson-logs/testlog.txt and build/meson-logs/testlog.junit.xml) attached?

Version 56-1 fails building for me with test failures, anything I missed?

----------------------------------------------------
 756   │ Summary of Failures:
 757   │
 758   │ 37/39 ddterm:pytest / test_app.TestApp                                                  FAIL            19.89s   exit status 1
 759   │
 760   │ Ok:                 38
 761   │ Expected Fail:      0
 762   │ Fail:               1
 763   │ Unexpected Pass:    0
 764   │ Skipped:            0
 765   │ Timeout:            0
------------------------------------------------
535   │ tmp_path = PosixPath('/tmp/pytest-of-greuelr/pytest-3/test_context_menu_leak_tab_0')
 536   │ widget = 'tab'
 537   │
 538   │     @pytest.mark.usefixtures('hide')
 539   │     @pytest.mark.parametrize('widget', ('terminal', 'tab'))
 540   │     def test_context_menu_leak(
 541   │         self,
 542   │         app_debug_dbus_interface,
 543   │         extension_dbus_interface,
 544   │         extension_test_hook,
 545   │         shell_test_hook,
 546   │         tmp_path,
 547   │         widget,
 548   │     ):
 549   │         extension_dbus_interface.Activate(timeout=dbusutil.DEFAULT_LONG_TIMEOUT_MS)
 550   │         extension_test_hook.wait_property('RenderedFirstFrame', True)
 551   │         app_debug_dbus_interface.wait_connected()
 552   │
 553   │         workarea = shell_test_hook.Workareas[0]
 554   │
 555   │         widget_location = {
 556   │             'terminal': workarea.center(),
 557   │             'tab': geometry.Point(workarea.center().x, workarea.y + workarea.height - 16)
 558   │         }[widget]
 559   │
 560   │         shell_test_hook.SetPointer(*widget_location)
 561   │
 562   │         dump_pre = tmp_path / 'heap-pre.dump'
 563   │         app_debug_dbus_interface.DumpHeap(dump_pre)
 564   │
 565   │         with shell_test_hook.watch_signal('WindowCreated') as window_created:
 566   │             shell_test_hook.Mouse2Down()
 567   │             shell_test_hook.Mouse2Up()
 568   │
 569   │ >           window_created.get()
 570   │
 571   │ ../gnome-shell-extension-ddterm-56/test/test_app.py:334:
 572   │ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
 573   │ ../gnome-shell-extension-ddterm-56/test/dbusutil.py:175: in get
 574   │     glibutil.wait_any_source(deadline.check_remaining_ms(), context=context)
 575   │ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
 576   │
 577   │ self = <test.glibutil.Deadline object at 0x7483801f2a30>
 578   │
 579   │     def check_remaining_ms(self):
 580   │         remaining_us = self.deadline_us - GLib.get_monotonic_time()
 581   │
 582   │         if remaining_us < 0:
 583   │ >           raise TimeoutError()
 584   │ E           TimeoutError
 585   │
 586   │ ../gnome-shell-extension-ddterm-56/test/glibutil.py:137: TimeoutError

Happy to see, that Gnome45 is now supported with version 48. But it looks like that glib-schemas have not been compiled automatically after upgrading the extension. I had to run sudo glib-compile-schemas /usr/share/gnome-shell/extensions/ddterm@amezin.github.com/schemas manually to make the extension work. Can we somehow add this to the post-install steps?

Sure will add when next version drops.