Download Xcode 27.1 and run your app in the iPhone Duo simulator using Device Hub. On-screen control buttons let you open, close, rotate, and fold the device to check your layout in every pose.
A pose matrix worth running
Poses multiply with orientation and multitasking, so test deliberately rather than by exploration:
| State | What to check |
|---|---|
| Closed, portrait | Compact-width layout on the outer display |
| Closed, landscape | Heavier toolbar overflow |
| Open flat, portrait | Regular width; sidebar should appear |
| Open flat, landscape | Vertical bars active |
| Partially folded | Division region active; nothing across the fold |
| Propped on a table | Content readable at distance in the top region; controls reachable in the bottom |
| Split View, various widths | Continuous reflow across the divider’s full range |
| Second scene open | Independent state in each window |
The transitions matter as much as the states. Most bugs surface while folding, not after.
Automate the parts you can
Snapshot tests at the two display sizes catch regressions cheaply once the layout is right:
- Inner display: 626 × 890 points
- Outer display: 466 × 678 points
These will not catch division regions or pose-specific behaviour, so keep the manual pass for those.
How to verify
Walk the matrix above once per release on your primary flows. Record the pass so a regression later has something to compare against.