QLPreviewController only renders its share, print and open-in actions
when it is inside a navigation controller, so diagram and report
previews were dead ends. Wrap it in one, add an explicit Done button
and assert both in a UI test.
The Overview share menu offered a wiring diagram and a full report even
for an empty system. Gate it on loads, batteries or chargers being
present (iOS + Android) and add UI tests for both states.
