Emulation

By leveraging iio-emu hardware or contexts can be emulated for testing without physical devices. However, currently this emulation does not validate attribute rates, states of drivers, or equivalent data sources. This feature should be used to test a library itself rather than hardware drivers.

Set up

To use device emulation you will need libtinyiiod and iio-emu libraries installed. pytest-libiio will take care of managing the iio-emu server automatically for you. iio-emu will also provide additional utilities incase XML need to be created for new devices.

Adding device support

Emulating hardware is done through a XML file generated from an existing hardware set up and pointing the tool xml_gen or gen-xml to the target context:

xml_gen ip:pluto.local > pluto.xml

This XML file can be manually used with pytest-libiio by leveraging the --emu-xml flag as so:

pytest --emu --emu-xml=pluto.xml

This will launch a server when testing is started with a device matching the provided context description in XML form.

Device library

pytest-libiio does ship with a number of built-in XML files for different devices. When the flag --emu is used without --emu-xml these will be dynamically loaded based on different required hardware as defined by pytest markers.

However, since not all tests work with emulated hardware there is a input available to the test markers to mark tests to not run when in emulation mode. This would work as follows:

import pytest
import iio


@pytest.mark.iio_hardware("pluto", True)  # Set True disables test during emulation
def test_libiio_device(iio_uri):
    ctx = iio.Context(iio_uri)
    ...

When adding new devices to the library itself, they must be defined in the hardware map. The default one is the adi_hardware_map.yml. To define the device the name of the XML file must be provided along with which drivers interface with data (TX or RX drivers). Here is an example:

pluto_rev_c:
  - ad9361-phy
  - cf-ad9361-lpc,2
  - ctx_attr:
    - hw_model: Analog Devices PlutoSDR Rev.C
  - emulate:
    - filename: pluto.xml
    - data_devices:
        - iio:device2
        - iio:device3
ad9081:
  - axi-ad9081-tx-hpc
  - axi-ad9081-rx-hpc
  - emulate:
    - filename: ad9081.xml
    - data_devices:
        - iio:device1
        - iio:device2

Note that the data_devices with names device* are the generic IIO driver names of the DMA drivers for TX and RX.