Pytest

The pytest framework helps developers writing test scripts from simple to complex. Pynvme is integrated with pytest, but it can also be used standalone.

Fixtures

Pytest’s fixture is a powerful way to create and free resources in the test. Pynvme provides following fixtures:

fixture	scope	notes
pciaddr	session	PCIe BDF address of the DUT, pass in by argument –pciaddr
pcie	session	the object of the PCIe device.
nvme0	session	the object of default NVMe controller
nvme0n1	session	the object of first Namespace of the default controller
verify	function	declare this fixture in test cases where data CRC is to be verified.

In the following example, the fixture nvme0n1 initializes the namespace for the test. Then, we can use it to start an ioworker directly. Super intuitive!

def test_ioworker_simplified_context(nvme0n1):
    with nvme0n1.ioworker(io_size=8, lba_align=16,
                          lba_random=True, qdepth=16,
                          read_percentage=0, time=2):
        pass

We no longer need to repeat nvme0n1 creation in every test case as usual way:

nvme0 = d.Controller(b'01:00.0')
nvme0n1 = d.Namespace(nvme0, 1)

Execution

With pytest and pre-defined makefile, we can execute tests in many flexible ways, like these:

# all tests under the directory
make test TESTS=scripts

# all tests in one file
make test TESTS=scripts/demo_test.py

# a specific test function
make test TESTS=scripts/utility_test.py::test_download_firmware

# a test function with a specified parameter
make test TESTS="driver_test.py::test_ioworker_iops_multiple_queue[1]"

# start tests on multiple drives with 1GB reserved memory space each
make test TESTS=scripts/stress/endurance_test.py::test_replay_jedec_client_trace pciaddr=01:00.0
make test TESTS=scripts/stress/endurance_test.py::test_replay_jedec_client_trace pciaddr=02:00.0
make test TESTS=scripts/stress/endurance_test.py::test_replay_jedec_client_trace pciaddr=172.168.5.44

Without specified pciaddr commandline parameter, make test automatically uses the last PCIe NVMe device in the lspci list. Pynvme supports multiple test sessions with different NVMe devices, or even NVMe over TCP targets, specified in the command line.