OpenPrinterVirtual Printer
Test protocol delivery and rendering without physical printer hardware.
A virtual printer participates in discovery and job delivery like a physical target but captures output locally instead of opening a device connection.
Use it to:
- develop an integrating server without printer hardware
- inspect the structured document sent by the server
- inspect rendered ESC/POS bytes and byte counts
- preview raster or receipt output when available
- test restart recovery and idempotency
- simulate predictable failures
Simulation modes
| Mode | Behavior |
|---|---|
| Always succeed | Captures output and returns a submission receipt |
| Fail next job | Fails once, then returns to success |
| Always fail | Returns a structured simulated failure |
| Delay submission | Waits for the configured bounded delay |
| Offline | Reports that the printer is unavailable |
The virtual printer never reports physical completion. A successful simulation produces the same submitted state used by other spoolers.
Local history
Captured output is bounded and stored as development-oriented local history. The UI can inspect or clear it. Diagnostics still avoid including complete print contents by default.
Automated tests
Agent lifecycle tests use the virtual spooler to verify the required order: persistence, receipt acknowledgement, rendering, submission, result persistence, and result reporting. This keeps CI independent of platform printer drivers.