pytest-blender

Pytest plugin for Blender testing. Executes your pytest testsuite with Blender in headless mode using its builtin Python interpreter.

Install

pip install pytest-blender

Documentation

Usage

Install dependencies in Blender Python interpreter

Before execute it, you need to install your testing dependencies inside the builtin Blender Python interpreter. To get the interpreter location you can use the CLI utility pytest-blender, something like:

blender_python="$(pytest-blender)"
$blender_python -m ensurepip
$blender_python -m pip install -r test-requirements.txt

You can also get the intepreter for a custom Blender installation location with --blender-executable option:

pytest-blender --blender-executable ~/blender-2.91.2-linux64/blender

Execute tests

After installing dependencies, just call pytest as usually.

pytest -svv

Blender 2.82 (sub 7)
Read prefs: ~/.config/blender/2.82/config/userpref.blend
========================= test session starts ==================================
platform linux -- Python 3.8.5, pytest-6.1.2, py-1.9.0, pluggy-0.13.1 -- /usr/bin/blender
cachedir: .pytest_cache
rootdir: /home/mondeja/files/code/pytest-blender
collected 1 item

tests/test_bpy_import.py::test_inside_blender <module 'bpy' from '/usr/share/blender/scripts/modules/bpy/__init__.py'>
PASSED
=========================== 1 passed in 0.01s ==================================

You can specify a custom blender executable path using --blender-executable option:

pytest --blender-executable ~/blender-2.91.2-linux64/blender

Blender 2.91.2 (hash 5be9ef417703 built 2021-01-19 16:16:34)
Read prefs: ~/.config/blender/2.91/config/userpref.blend
found bundled python: ~/blender-2.91.2-linux64/2.91/python
============================ test session starts ===============================
platform linux -- Python 3.7.7, pytest-6.2.2, py-1.10.0, pluggy-0.13.1
rootdir: ~/pytest-blender
collected 1 item

tests/test_bpy_import.py .                                                [100%]

============================== 1 passed in 0.00s ===============================

Arguments propagation

When you call pytest, all options like --blender-executable are passed to the pytest suite running pytest-blender. If you want to pass arguments to blender in its headless execution, add a -- between pytest and blender arguments. If you want to pass arguments to the python Blender's interpreter, you need to add another -- between arguments in a third group.

For example:

pytest -svv --blender-executable ~/blender -- --enable-event-simulate -- -b

In case that you don't want to pass arguments to blender but yes to python, use double arguments group separation (-- --):

pytest -svv -- -- -b

Load startup template

You can use the --blender-template argument to pass a custom startup file:

pytest -svv --blender-template ~/.config/blender/2.93/config/startup.blend

Reference

Fixtures

# blender_executable ⇒ str

Returns the path of the executable that has started the current Blender session.

# blender_version ⇒ str

Returns the version of Blender running in the current session.

# blender_python_executable ⇒ str

Returns the path of the Python executable builtin in the Blender release of the currently running session.

# blender_python_version ⇒ str

Returns the version of the Python executable builtin in the Blender release of the currently running session.

# install_addons_from_dir(addons_dir, addon_module_names=None, recursive=False, save_userpref=True, default_set=True, persistent=True, **kwargs) ⇒ list

Function that installs and enables a set of addons whose modules are located in a directory. This function is designed to be executed before the pytest session to install the addons that you want to test, using the other fixture disable_addons to disable them after the execution of the test suite:

import os

import pytest

@pytest.fixture(scope="session", autouse=True)
def _register_addons(request, install_addons_from_dir, disable_addons):
    addon_module_names = install_addons_from_dir(os.path.abspath("src"))
    yield
    disable_addons(addon_module_names)

addons_dir (str) Directory in which are located the modules of the addons.
addon_module_names (list) Name of the addons modules. If not defined (default) these will be discovered searching for addons in addons_dir directory. By default the discovering is not recursive through subdirectories, but you can enable it using the recursive argument.
recursive (bool) If addon_module_names is not defined, the discovering of addons inside addons_dir is done recursively through subdirectories.
save_userpref (bool) Save user preferences after installation.
default_set (bool) Set the user-preference calling addon_utils.enable.
persistent (bool) Ensure the addon is enabled for the entire session (after loading new files).
**kwargs (dict) Subsecuent keyword arguments are passed to bpy.ops.preferences.addon_install.

Returns the addon module names as a list, ready to be passed to disable_addons function.

# disable_addons(addon_module_names, save_userpref=True, default_set=True, **kwargs)

Function that disables a set of addons by module name. Is designed to disable your addons after a pytest suite execution (check install_addons_from_dir for an example).

addon_module_names (list) Name of the addons modules (without the .py extension).
save_userpref (bool) Save user preferences after installation.
default_set (bool) Set the user-preference calling addon_utils.disable.
**kwargs (dict) Subsecuent keyword arguments are passed to addon_utils.disable.

CI integration

You can use blender-downloader to download multiple versions of Blender in your CI and test against them. There is an example for Github Actions in the CI configuration of this repository:

jobs:
  test:
    name: Test
    runs-on: ${{ matrix.platform }}
    strategy:
      matrix:
        platform:
          - ubuntu-latest
          - macos-latest
        blender-version:
          - '2.90.1'
          - '2.83.9'
          - '2.82'
          - '2.81'
          - '2.80'
    steps:
      - uses: actions/checkout@v2
      - name: Set up Python v3.8
        uses: actions/setup-python@v2
        with:
          python-version: 3.8
      - name: Upgrade PIP
        run: python -m pip install --upgrade pip
      - name: Cache Blender ${{ matrix.blender-version }}
        uses: actions/cache@v2.1.5
        id: cache-blender
        with:
          path: |
            blender-*
            _blender-executable-path.txt
          key: ${{ runner.os }}-${{ matrix.blender-version }}
      - name: Download Blender ${{ matrix.blender-version }}
        if: steps.cache-blender.outputs.cache-hit != 'true'
        id: download-blender
        run: |
          python -m pip install --upgrade blender-downloader
          echo "$(blender-downloader \
          ${{ matrix.blender-version }} --extract --remove-compressed \
          --quiet --print-blender-executable)" > _blender-executable-path.txt
      - name: Install dependencies
        id: install-dependencies
        run: |
          python -m pip install .[test]
          blender_executable="$(< _blender-executable-path.txt tr -d '\n')"
          python_blender_executable="$(pytest-blender --blender-executable $blender_executable)"
          $python_blender_executable -m ensurepip
          $python_blender_executable -m pip install pytest
          echo "::set-output name=blender-executable::$blender_executable"
      - name: Test with pytest
        run: pytest -svv --blender-executable "${{ steps.install-dependencies.outputs.blender-executable }}" tests

superstar54/pytest-blender