95 lines
2.9 KiB
Markdown
95 lines
2.9 KiB
Markdown
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`umockdev` Tests
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================
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`umockdev` tests use fingerprint devices mocked by [`umockdev`
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toolchain][umockdev].
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This document describes how to create a 'capture' test: a test that
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captures a picture of a fingerprint from the device (mocked by
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`umockdev`) and compares it with the standard one.
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Other kinds of `umockdev` tests could be created in a similar manner.
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'Capture' Test Creation
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-----------------------
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A new 'capture' test is created by means of `capture.py` script:
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1. Create (if needed) a directory for the driver under `tests`
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directory:
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`mkdir DRIVER`
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2. Prepare your execution environment.
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In the next step a working and up to date libfprint is needed. This can be
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achieved by installing it into your system. Alternatively, you can set
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the following environment variables to run a local build:
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- `export LD_PRELOAD=<meson-build-dir>/libfprint/libfprint-2.so`
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- `export GI_TYPELIB_PATH=<meson-build-dir>/libfprint`
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Also, sometimes the driver must be adopted to the emulated environment
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(mainly if it uses random numbers, see `synaptics.c` for an example).
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Set the following environment variable to enable this adaptation:
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- `export FP_DEVICE_EMULATION=1`
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Run the next steps in the same terminal.
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3. Find the real USB fingerprint device with `lsusb`, e.g.:
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`Bus 001 Device 005: ID 138a:0090 Validity Sensors, Inc. VFS7500 Touch Fingerprint Sensor`
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The following USB device is used in the example above:
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`/dev/bus/usb/001/005`.
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4. Record information about this device:
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`umockdev-record /dev/bus/usb/001/005 > DRIVER/device`
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5. Record interaction of `capture.py` (or other test) with the device:
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`umockdev-record -i /dev/bus/usb/001/005=DRIVER/capture.ioctl -- python3 ./capture.py DRIVER/capture.png`
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Files `capture.ioctl` and `capture.png` will be created as the
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result of this command.
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6. Add driver's name to `drivers_tests` in the `meson.build`.
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7. Check whether everything works as expected.
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**Note.** To avoid submitting a real fingerprint, the side of finger,
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arm, or anything else producing an image with the device can be used.
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Possible Issues
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---------------
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`umockdev-record` aggressively groups URBs. In most cases, manual
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intervention is unfortunately required. Often, drivers do a chain of
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commands like: A then B each with a different reply. However,
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`umockdev-record` could create a file like this:
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A
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reply 1
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reply 2
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B
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reply 1
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reply 2
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In that case, records must be re-ordered:
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A
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reply 1
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B
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reply 1
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A
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reply 2
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B
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reply 2
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Other changes may be needed to get everything working. For example the
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`elan` driver relies on a timeout that is not reported correctly. In
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this case the driver works around it by interpreting the protocol
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error differently in the virtual environment (by means of
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`FP_DEVICE_EMULATION` environment variable).
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[umockdev]: https://github.com/martinpitt/umockdev
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