{Overview.} This fixture stands in for xdg-desktop-portal so that tests can exercise portal-backed PipeWire code paths without a human present. The real stack looks like:
client (e.g. QPipeWireCaptureHelper)
-> xdg-desktop-portal (interactive consent dialog)
-> compositor's PipeWire node
QFakeXdgPortalFixture (qfakexdgportalfixture_p.h) replaces the middle two: it starts a private, hardware-free pipewire daemon, then re-execs the test binary itself as a helper process on a private D-Bus session bus with no service activation, so the real xdg-desktop-portal can never be reached. That helper process is what this namespace implements. It owns org.freedesktop.portal.Desktop and answers portal calls immediately with canned, always-successful responses (FakePortalObject and its per-interface QDBusAbstractAdaptor subclasses in qfakexdgportal.cpp), backed by a QSyntheticPipeWireVideoSource (qsyntheticpipewirevideosource_p.h) that publishes a synthetic, painter-generated frame as if it came from a real screen or camera. A private org.qtproject.qtmultimedia.FakeXdgPortal D-Bus interface lets the fixture drive the helper from the test process (change the published scene, force a specific response code, and so on).
1.18.0