Initial commit

.gitignore

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+# Byte-compiled / optimized / DLL files
+__pycache__/
+*.py[cod]
+*$py.class
+
+# C extensions
+*.so
+
+# Distribution / packaging
+.Python
+build/
+develop-eggs/
+dist/
+downloads/
+eggs/
+.eggs/
+lib/
+lib64/
+parts/
+sdist/
+var/
+wheels/
+pip-wheel-metadata/
+share/python-wheels/
+*.egg-info/
+.installed.cfg
+*.egg
+MANIFEST
+
+# PyInstaller
+#  Usually these files are written by a python script from a template
+#  before PyInstaller builds the exe, so as to inject date/other infos into it.
+*.manifest
+*.spec
+
+# Installer logs
+pip-log.txt
+pip-delete-this-directory.txt
+
+# Unit test / coverage reports
+htmlcov/
+.tox/
+.nox/
+.coverage
+.coverage.*
+.cache
+nosetests.xml
+coverage.xml
+*.cover
+*.py,cover
+.hypothesis/
+.pytest_cache/
+
+# Translations
+*.mo
+*.pot
+
+# Django stuff:
+*.log
+local_settings.py
+db.sqlite3
+db.sqlite3-journal
+
+# Flask stuff:
+instance/
+.webassets-cache
+
+# Scrapy stuff:
+.scrapy
+
+# Sphinx documentation
+docs/_build/
+
+# PyBuilder
+target/
+
+# Jupyter Notebook
+.ipynb_checkpoints
+
+# IPython
+profile_default/
+ipython_config.py
+
+# pyenv
+.python-version
+
+# pipenv
+#   According to pypa/pipenv#598, it is recommended to include Pipfile.lock in version control.
+#   However, in case of collaboration, if having platform-specific dependencies or dependencies
+#   having no cross-platform support, pipenv may install dependencies that don't work, or not
+#   install all needed dependencies.
+#Pipfile.lock
+
+# PEP 582; used by e.g. github.com/David-OConnor/pyflow
+__pypackages__/
+
+# Celery stuff
+celerybeat-schedule
+celerybeat.pid
+
+# SageMath parsed files
+*.sage.py
+
+# Environments
+.env
+.venv
+env/
+venv/
+ENV/
+env.bak/
+venv.bak/
+
+# Spyder project settings
+.spyderproject
+.spyproject
+
+# Rope project settings
+.ropeproject
+
+# mkdocs documentation
+/site
+
+# mypy
+.mypy_cache/
+.dmypy.json
+dmypy.json
+
+# Pyre type checker
+.pyre/

.pre-commit-config.yaml

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+# See https://pre-commit.com for more information
+# See https://pre-commit.com/hooks.html for more hooks
+
+repos:
+
+-   repo: https://github.com/pre-commit/pre-commit-hooks
+    rev: v3.4.0
+    hooks:
+    -   id: end-of-file-fixer
+    -   id: trailing-whitespace
+    -   id: check-yaml
+
+-   repo: https://github.com/asottile/pyupgrade
+    rev: v2.11.0
+    hooks:
+    -   id: pyupgrade
+        args: ["--py38-plus"]
+
+-   repo: https://github.com/asottile/seed-isort-config
+    rev: v2.2.0
+    hooks:
+    -   id: seed-isort-config
+
+-   repo: https://github.com/pre-commit/mirrors-isort
+    rev: v5.8.0
+    hooks:
+    -   id: isort
+        additional_dependencies:
+          - toml
+
+-   repo: https://github.com/ambv/black
+    rev: 20.8b1
+    hooks:
+    - id: black
+      args: [--line-length=88, --safe]
+
+-   repo: https://github.com/pycqa/pylint
+    rev: pylint-2.7.4
+    hooks:
+    -   id: pylint
+        args: [--extension-pkg-whitelist=django]
+        additional_dependencies: ["Django"]
+
+-   repo: https://github.com/pre-commit/mirrors-mypy
+    rev: v0.812
+    hooks:
+      - id: mypy

LICENSE

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+MIT License
+
+Copyright (c) 2021 Sid Mitra
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

README.md

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+# django-parallel-test
+
+Django test runner to run a test suite across different machines.
+
+It supports any CI system, like Heroku CI, Jenkins, Travis etc.
+
+## Quickstart
+
+To run the test suite on machine 1 out of a total 3, run the following:
+
+```shell
+pip install django-parallel-test
+
+CI_NODE_INDEX=0 CI_NODE_TOTAL=3 python manage.py test --testrunner=django_parallel_test.ParallelRunner
+```
+
+### Heroku
+
+Additional steps are needed for Heroku to enable parallel dynos.
+
+- Update `app.json`, to add the quantity of dynos you want to run the tests on.
+
+To run your tests on 3 dynos in parallel, your config will look something like
+the following.
+
+```json
+...
+  "test": {
+    "formation": {
+      "test": {
+        "quantity": 3,
+      }
+    },
+    "scripts": {
+      "test": "python manage.py test --testrunner=django_parallel_test.ParallelRunner",
+    }
+  }
+...
+```
+
+Heroku already adds the config vars `CI_NODE_INDEX`_ and `CI_NODE_TOTAL`, so
+you do not need to add it explicitly
+
+- Commit and push to watch it in action!
+
+![Heroku CI](/images/heroku-ci.png)
+
+### References
+
+- [Heroku CI Parallel Test Runs](https://devcenter.heroku.com/articles/heroku-ci-parallel-test-runs)
+- [Heroku CI Updates: Parallel Tests, CI API, and Automated UAT](https://blog.heroku.com/ci-parallel-tests)
+
+## Other CI
+
+- You can add the environment variables to your settings.py instead
+
+```python
+TEST_RUNNER = "django_parallel_test.HerokuParallelRunner"  # or using --runner param
+CI_NODE_TOTAL = os.environ.get("CI_NODE_TOTAL", 1)  # total number of CI dynos
+CI_NODE_INDEX = os.environ.get("CI_NODE_INDEX", 0)  # index of the current dyno
+```

django_parallel_test.py

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+"""
+Custom Django test runner
+"""
+from __future__ import annotations
+
+import logging
+import os
+
+from django.conf import settings
+from django.test.runner import DiscoverRunner
+
+logger = logging.getLogger(__name__)
+
+
+__all__ = ["ParallelRunner"]
+
+
+class ParallelRunner(DiscoverRunner):
+    """
+    Django test runner that runs the test suite in parallel on different machines
+
+    It divides the entire test suite into different subsets and runs one particular
+    subset on each of the dynos. It uses the variables `CI_NODE_TOTAL, CI_NODE_INDEX` in
+    django settings or environment variables to select which subset to run on which
+    machine.
+    """
+
+    @property
+    def ci_node_total(self) -> int:
+        """
+        Return total number of dynos that will run the tests.
+        """
+        if hasattr(settings, "CI_NODE_TOTAL"):
+            return int(settings.CI_NODE_TOTAL)
+
+        return int(os.environ.get("CI_NODE_TOTAL", 1))
+
+    @property
+    def ci_node_index(self) -> int:
+        """
+        Return index number of the current machine out of total machines available.
+        """
+        if hasattr(settings, "CI_NODE_INDEX"):
+            return int(settings.CI_NODE_INDEX)
+
+        return int(os.environ.get("CI_NODE_INDEX", 0))
+
+    def split_suite(self, suite):
+        """
+        Return a subset of the test classes in the suite to be run on the current node.
+        """
+
+        def get_class_name(test_method):
+            return str(test_method.__class__)
+
+        # Get a list of all test classes we found in the suite.
+        classes = sorted({get_class_name(test_method) for test_method in suite})
+        # Only select a subset of the test classes to be run on the node.
+        classes_subset = [
+            test_class
+            for idx, test_class in enumerate(classes)
+            if idx % self.ci_node_total == self.ci_node_index
+        ]
+
+        # Create a new test suite with only test methods from the subset of classes.
+        suite_class = type(suite)
+        new_suite = suite_class()
+        count = 0
+        for test_method in suite:
+            if get_class_name(test_method) in classes_subset:
+                count += 1
+                new_suite.addTest(test_method)
+        logger.info(
+            f"{count} tests will be run on this node from the following classes:"
+            f"\n{classes_subset}"
+        )
+        return new_suite
+
+    def run_suite(self, suite, **kwargs):
+        """
+        Run the entire test suite.
+        """
+        if self.parallel > 1:
+            logger.warning(
+                "--parallel is not supported by this runner. "
+                "Please use `quantity` key in app.json to increase number of "
+                "nodes instead, if using Heroku"
+            )
+            raise ValueError("Unsupported parameter passed `--parallel`.")
+
+        suite_with_subset = self.split_suite(suite)
+        return super().run_suite(suite_with_subset, **kwargs)