No subject

The test backend is a SANE backend designed to test frontends and as
an example of what SANE is able to do. No scanner or other device is
needed for this driver so frontend programmers can test the more
obscure scan modes and options also. Everything the pnm backend can do
(but reading PNM files) is or will be supported. This code is ALPHA
level software. There is no documentation but this page and the source
code yet.

Supported features

The backend provides an (almost) unlimited number of virtual devices.
The default is 2. The value can be adjusted in the test.conf file.

All single-pass scan-modes are supported (1, 8, 16 bit depth, gray and
rgb scans). Geometry and resolution can be adjusted to (almost)
unlimeted values. The actual values and their minima and maxima can be
set in test.conf. Be carefull, even with the default settings the
image size can reach about 500 MB. Scanning results in pure black
images. The backend tries to catch all errors it can and print
messages. Set SANE_DEBUG_TEST=255 to see them.

Bye,
  Henning