Allow multiple tests per driver by using the first section of the directory name, before the separating '-', as the driver name.
3 KiB
umockdev
Tests
umockdev
tests use fingerprint devices mocked by umockdev
toolchain.
This document describes how to create a 'capture' test: a test that
captures a picture of a fingerprint from the device (mocked by
umockdev
) and compares it with the standard one.
Other kinds of umockdev
tests can be created in a similar manner. For
match-on-chip devices you would instead create a test specific custom.py
script, capture it and store the capture to custom.pcapng
.
'Capture' Test Creation
A new 'capture' test is created by means of capture.py
script:
-
Create (if needed) a directory for the driver under
tests
directory:mkdir DRIVER
Note that the name must be the exact name of the libfprint driver, or the exact name of the driver followed by a
-
and a unique identifier of your choosing. -
Prepare your execution environment.
In the next step a working and up to date libfprint is needed. This can be achieved by installing it into your system. Alternatively, you can set the following environment variables to run a local build:
export LD_PRELOAD=<meson-build-dir>/libfprint/libfprint-2.so
export GI_TYPELIB_PATH=<meson-build-dir>/libfprint
Also, sometimes the driver must be adapted to the emulated environment (mainly if it uses random numbers, see
synaptics.c
for an example). Set the following environment variable to enable this adaptation:export FP_DEVICE_EMULATION=1
Run the next steps in the same terminal.
-
Find the real USB fingerprint device with
lsusb
, e.g.:Bus 001 Device 005: ID 138a:0090 Validity Sensors, Inc. VFS7500 Touch Fingerprint Sensor
The following USB device is used in the example above:
/dev/bus/usb/001/005
.For the following commands, it is assumed that the user that's running the commands has full access to the device node, whether by running the commands as
root
, or changing the permissions for that device node. -
Record information about this device:
umockdev-record /dev/bus/usb/001/005 > DRIVER/device
-
Record interaction of
capture.py
(or other test) with the device. To do so, start wireshark and recordusbmonX
(where X is the bus number). Then run the test script:python3 ./capture.py DRIVER/capture.png
Save the wireshark recording as
capture.pcapng
. The command will createcapture.png
. -
Add driver's name to
drivers_tests
in themeson.build
. -
Check whether everything works as expected.
Note. To avoid submitting a real fingerprint, the side of finger, arm, or anything else producing an image with the device can be used.
Possible Issues
Other changes may be needed to get everything working. For example the
elan
driver relies on a timeout that is not reported correctly. In
this case the driver works around it by interpreting the protocol
error differently in the virtual environment (by means of
FP_DEVICE_EMULATION
environment variable).