I have to admit, after adding the final test for checking the Nornir course code repo, it felt good. 56 tests in total. Job done! Well, kind of. After performing a final run and feeling smug that I was getting a screen of green passes, it raised the next question:
How can I speed up Pytest to run faster?
As it stood, it took around 2 minutes to run all the tests due to Pytest running them sequentially.
After some quick Googling, I discovered the awesome tool - pytest-xdist. In a nutshell, pytest-xdist is a Pytest plugin that (from the pytest-xdist repo):
extends Pytest with new test execution modes, the most used being distributing tests across multiple CPUs to speed up test execution.
Great! Here's a quick example:
# Install (for pip users, perform a pip install pytest-xdist, instead).
$ poetry add pytest-xdist
# Use -n auto to spawn work processes equal to CPUs and distribute tests across them.
$ pytest -v tests/ -n auto
...
The result? The testing was reduced from 2mins to ~30 secs!
$ pytest -v tests/ -n auto
========================================================================================================= test session starts =========================================================================================================
platform linux -- Python 3.8.5, pytest-7.1.1, pluggy-1.0.0 -- /home/rick/.cache/pypoetry/virtualenvs/nornir-course-iatnHwlm-py3.8/bin/python
cachedir: .pytest_cache
rootdir: /mnt/c/Users/rick/nornir-course
plugins: forked-1.4.0, xdist-2.5.0
[gw0] linux Python 3.8.5 cwd: /mnt/c/Users/rick/nornir-course
[gw1] linux Python 3.8.5 cwd: /mnt/c/Users/rick/nornir-course
[gw2] linux Python 3.8.5 cwd: /mnt/c/Users/rick/nornir-course
...
[gw0] Python 3.8.5 (default, Jan 27 2021, 15:41:15) -- [GCC 9.3.0]
[gw1] Python 3.8.5 (default, Jan 27 2021, 15:41:15) -- [GCC 9.3.0]
[gw2] Python 3.8.5 (default, Jan 27 2021, 15:41:15) -- [GCC 9.3.0]
[gw3] Python 3.8.5 (default, Jan 27 2021, 15:41:15) -- [GCC 9.3.0]
...
gw0 [56] / gw1 [56] / gw2 [56] / gw3 [56] / gw4 [56] / gw5 [56] / gw6 [56] / gw7 [56]
scheduling tests via LoadScheduling
tests/test_003_inventory.py::test_nr_print_inventory_dynamic
tests/test_003_inventory.py::test_nr_print_inventory_static
tests/test_003_inventory.py::test_nr_cred_inject
tests/test_002_config.py::test_inspect_config
tests/test_001_fundamentals.py::test_run_first_test
tests/test_002_config.py::test_set_config_dict
tests/test_003_inventory.py::test_nr_inspect_inventory
tests/test_002_config.py::test_set_config_yaml
[gw1] [ 1%] PASSED tests/test_002_config.py::test_set_config_yaml
[gw2] [ 3%] PASSED tests/test_002_config.py::test_set_config_dict
[gw6] [ 5%] PASSED tests/test_003_inventory.py::test_nr_cred_inject
[gw3] [ 7%] PASSED tests/test_002_config.py::test_inspect_config
tests/test_004_tasks.py::test_changed
tests/test_004_tasks.py::test_creating_a_task
tests/test_003_inventory.py::test_f_object_filtering
tests/test_004_tasks.py::test_running_a_task
[gw4] [ 8%] PASSED tests/test_003_inventory.py::test_nr_print_inventory_static
tests/test_004_tasks.py::test_grouping_tasks
[gw7] [ 10%] PASSED tests/test_003_inventory.py::test_nr_inspect_inventory
tests/test_004_tasks.py::test_failed
[gw3] [ 12%] PASSED tests/test_004_tasks.py::test_creating_a_task
[gw6] [ 14%] PASSED tests/test_004_tasks.py::test_changed
...
tests/test_009_imports.py::test_imports[007_plugins/004_scrapli.py]
[gw6] [ 94%] PASSED tests/test_009_imports.py::test_imports[007_plugins/002_netmiko.py]
[gw2] [ 96%] PASSED tests/test_009_imports.py::test_imports[007_plugins/003_napalm.py]
[gw3] [ 98%] PASSED tests/test_008_processors.py::test_progress_bar
[gw0] [100%] PASSED tests/test_009_imports.py::test_imports[008_processors/002_progress_bars.py]
========================================================================================================== warnings summary ===========================================================================================================
...
================================================================================================== 56 passed, 26 warnings in 29.16s ===================================================================================================
Great stuff!
