Add tests setup and first tests

Author: adamalton

massmigration/tests/__init__.py

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+# Standard library
+import os
+import shutil
+
+# Third party
+from django.apps.registry import apps
+from django.core.management import execute_from_command_line
+from django.test import TestCase
+
+# Mass Migration
+from massmigration.constants import MIGRATIONS_FOLDER
+
+
+class MakeMassMigrationTestCase(TestCase):
+    """ Tests for the 'makemassmigration' command. """
+
+    def tearDown(self):
+        super().tearDown()
+        self.delete_massmigrations_folder()
+
+    def migrations_folder_path(self, app_name="massmigration"):
+        """ The expected folder path where the command will put the migration files. """
+        app = apps.get_app_config(app_name)
+        return os.path.join(app.path, MIGRATIONS_FOLDER)
+
+    def delete_massmigrations_folder(self, app_name="massmigration"):
+        """ Delete the folder which the command puts the migration files into. """
+        path = self.migrations_folder_path(app_name)
+        if os.path.exists(path):
+            shutil.rmtree(path)
+
+    def get_migration_file(self, file_name, app_name="massmigration"):
+        """ Return the file contents of the given migration file. """
+        file_path = os.path.join(self.migrations_folder_path(app_name), file_name)
+        with open(file_path) as file:
+            return file.read()
+
+    def assert_migration_file_exists(self, file_name, app_name="massmigration"):
+        file_path = os.path.join(self.migrations_folder_path(app_name), file_name)
+        if not os.path.exists(file_path):
+            self.fail(f"Migration file not found at {file_path}")
+
+    def run_command(self, file_name, *args, app_name="massmigration"):
+        execute_from_command_line([
+            "django-admin",
+            "makemassmigration",
+            app_name,
+            file_name,
+            *args,
+        ])
+
+    def test_increments_numbers(self):
+        self.run_command("first_migration")
+        self.assert_migration_file_exists("0001_first_migration.py")
+        self.run_command("second_migration")
+        self.assert_migration_file_exists("0002_second_migration.py")
+
+    def test_uses_correct_template(self):
+        for index, (template, expected_base_class) in enumerate([
+            ("simple", "SimpleMigration"),
+            ("mapper", "MapperMigration"),
+            ("custom", "BaseMigration"),
+        ]):
+            self.run_command("my_migration", "--template", template)
+            file_contents = self.get_migration_file(f"000{index + 1}_my_migration.py")
+            self.assertIn(f"\nclass Migration({expected_base_class}):\n", file_contents)

massmigration/tests/test_commands.py

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+#!/usr/bin/env python3
+
+""" Builds a Docker image locally to run the tests (if it's not already built), then uses it to run
+    the massmigration tests.
+"""
+
+import os
+import subprocess
+import sys
+
+
+IMAGE_NAME = "django-mass-migrations-test"
+
+
+def abort(msg):
+    print(f"🚨 {msg}")
+    sys.exit(1)
+
+
+def check_have_docker():
+    try:
+        subprocess.check_call(["which", "docker"])
+    except subprocess.CalledProcessError:
+        abort(
+            "It looks like you don't have the 'docker' command installed. "
+            "This utility script uses Docker to run the tests."
+        )
+
+
+def project_folder():
+    scripts_dir = os.path.dirname(os.path.abspath(__file__))
+    return os.path.dirname(scripts_dir)
+
+
+def dockerfile_path():
+    return os.path.join(project_folder(), "testing", "Dockerfile")
+
+
+def image_exists():
+    output = subprocess.check_output(["docker", "images", "-q", IMAGE_NAME])
+    return bool(output.strip())
+
+
+def build_image():
+    subprocess.check_call([
+        "docker",
+        "build",
+        "-t",
+        IMAGE_NAME,
+        "--file",
+        dockerfile_path(),
+        project_folder(),
+    ])
+
+
+def run_tests():
+    subprocess.check_call(
+        [
+            "docker",
+            "run",
+            "--rm",
+            "--volume",
+            f"{project_folder()}/massmigration:/code/massmigration",
+            IMAGE_NAME,
+            *sys.argv[1:],
+        ],
+        cwd=project_folder(),
+    )
+
+
+def main():
+    check_have_docker()
+    if not image_exists():
+        build_image()
+    run_tests()
+
+
+if __name__ == '__main__':
+    main()

scripts/run_tests_locally.py

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+FROM python:3.10-slim
+
+ENV PYTHONUNBUFFERED 1
+
+RUN mkdir /code
+WORKDIR /code
+COPY . /code/
+
+# Install *this* package in editable mode. If we then mount the 'massmigration' folder as a volume
+# when running the Docker container, it should pick up local changes to the files.
+RUN pip install -e .
+COPY . /code/
+
+ENV DJANGO_SETTINGS_MODULE "testing.test_settings"
+
+ENTRYPOINT ["./testing/docker_entrypoint.sh"]

testing/Dockerfile

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+#!/bin/sh
+
+# A shell script to be used as the ENTRYPOINT for the Docker container for running tests so that
+# the passed arguments (i.e. test name(s)) can be passed through to Django.
+
+django-admin test massmigration $@

testing/docker_entrypoint.sh

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+""" Barebones settings for running tests for 'massmigration' app. """
+
+from pathlib import Path
+
+# Build paths inside the project like this: BASE_DIR / 'subdir'.
+BASE_DIR = Path(__file__).resolve().parent.parent
+
+
+SECRET_KEY = 'MASSMIGRATION_TEST_SECRET_KEY'
+
+DEBUG = True
+
+ALLOWED_HOSTS = []
+
+
+INSTALLED_APPS = [
+    'django.contrib.admin',
+    'django.contrib.auth',
+    'django.contrib.contenttypes',
+    'django.contrib.sessions',
+    'django.contrib.messages',
+    'django.contrib.staticfiles',
+    'massmigration',
+]
+
+MIDDLEWARE = [
+    'django.middleware.security.SecurityMiddleware',
+    'django.contrib.sessions.middleware.SessionMiddleware',
+    'django.middleware.common.CommonMiddleware',
+    'django.middleware.csrf.CsrfViewMiddleware',
+    'django.contrib.auth.middleware.AuthenticationMiddleware',
+    'django.contrib.messages.middleware.MessageMiddleware',
+    'django.middleware.clickjacking.XFrameOptionsMiddleware',
+]
+
+ROOT_URLCONF = 'massmigration.urls'
+
+TEMPLATES = [
+    {
+        'BACKEND': 'django.template.backends.django.DjangoTemplates',
+        'DIRS': [],
+        'APP_DIRS': True,
+        'OPTIONS': {
+            'context_processors': [
+                'django.template.context_processors.debug',
+                'django.template.context_processors.request',
+                'django.contrib.auth.context_processors.auth',
+                'django.contrib.messages.context_processors.messages',
+            ],
+        },
+    },
+]
+
+# WSGI_APPLICATION = '{{ project_name }}.wsgi.application'
+
+
+DATABASES = {
+    'default': {
+        'ENGINE': 'django.db.backends.sqlite3',
+        'NAME': ':memory:',
+    }
+}
+
+DEFAULT_AUTO_FIELD = 'django.db.models.BigAutoField'