Clone this repo:
  1. f2f199d Reland "virtual-usb-printer: fix unit tests" by Paul Moy · 6 hours ago chromeos
  2. 8c2bbc2 Revert "virtual-usb-printer: fix unit tests" by Aaron Massey · 2 days ago
  3. 24080ed Revert "virtual-usb-printer: Allow empty IPP responses" by Aaron Massey · 2 days ago
  4. bda7736 virtual-usb-printer: Allow empty IPP responses by Paul Moy · 2 days ago
  5. d10a77b virtual-usb-printer: fix unit tests by Paul Moy · 2 days ago

Virtual USB Printer

Virtual USB Printer provides a server which can be used with USBIP in order to emulate a USB printing device and bind it to the system as if it were physically connected to a USB port.

Virtual USB Printer supports both regular USB printers as well as IPP-over-USB devices.

Motivation

This project was created in order to make on-device tests which check for any regressions in the native USB printing system.

Installation

As of https://crrev.com/c/3093381, virtual-usb-printer is built and installed by default on all test images that support it.

If for some reason you need to build it yourself, you can USE=usbip when building packages for your board - i.e.

USE="usbip" ./build_packages --board=$BOARD
virtual-usb-printer relies on usbip to manifest as a virtual USB device. Most test images seem to come with this built-in by default. If you need to build your own kernel with usbip support, make sure to build with CONFIG_USBIP_CORE and CONFIG_USBIP_VHCI_HCD.

How to Use

virtual-usb-printer can behave like

For ease of human operation, start virtual-usb-printer via its Upstart unit. Pass the appropriate arguments to the invocation as needed.

For example, to start and connect the virtual-usb-printer as an IPP-over-USB printer, issue

start virtual-usb-printer USB_DESCRIPTORS=ippusb_printer.json IPP_ATTRIBUTES=ipp_attributes.json

Consult the Upstart config file to see the arguments understood in this context.

When managed by Upstart, virtual-usb-printer sends its output to the system log.

Configuration

The printer's USB descriptors and defined IPP attributes can be configured using a JSON file and are loaded at run-time using command line flags. Example configurations can be found in the config/ directory.

The configuration files can be loaded with the following flags:

  • --descriptors_path - full path to the JSON file which defines the USB descriptors
  • --attributes_path - full path to the JSON file which defines the supported IPP attributes
    • Only needed for IPP-over-USB printer configurations
  • --record_doc_path - full path to the file used to record documents received from print jobs
  • --output_log_dir - directory path specifying where scan settings will be logged

Using in Tast

Refer to these existing tast tests for examples of how to use the virtual-usb-printer to test the Chromium OS printing stack.

Print Tests

Scan Tests