test: add foreign key tests (#807)

Author: IlyaFaer

.github/workflows/foreign_keys.yaml

@@ -0,0 +1,30 @@
+on:
+  push:
+    branches:
+      - main
+  pull_request:
+name: foreign-keys-test
+jobs:
+  system-tests:
+    runs-on: ubuntu-latest
+
+    services:
+      emulator-0:
+        image: gcr.io/cloud-spanner-emulator/emulator:latest
+        ports:
+          - 9010:9010
+
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v3
+      - name: Setup Python
+        uses: actions/setup-python@v4
+        with:
+          python-version: 3.8
+      - name: Run Django foreign key test
+        run: sh foreign_key_test.sh
+        env:
+          SPANNER_EMULATOR_HOST: localhost:9010
+          GOOGLE_CLOUD_PROJECT: emulator-test-project
+          GOOGLE_CLOUD_TESTS_CREATE_SPANNER_INSTANCE: true
+          SPANNER_TEST_INSTANCE: google-cloud-django-backend-tests

foreign_key_test.sh

@@ -0,0 +1,42 @@
+pip install django==3.2
+
+mkdir django_test
+cd django_test
+
+django-admin startproject foreign_keys
+cd foreign_keys
+python manage.py startapp applic
+
+echo "
+from django.db import models
+
+
+class Country(models.Model):
+    name = models.CharField(max_length=32)
+
+
+class City(models.Model):
+    name = models.CharField(max_length=32)
+    country = models.ForeignKey(Country, on_delete=models.DO_NOTHING)
+" > applic/models.py
+
+
+echo "from django.test import TestCase
+from .models import City, Country
+
+
+class EnqueuedRoutesTest(TestCase):
+    def setUp(self):
+        self.country = Country.objects.create(name='Country123')
+        self.city = City.objects.create(name='City123', country=self.country)
+    
+    def test_foreign_key(self):
+        city = City.objects.get(pk=1)
+        assert city.country == Country.objects.get(pk=1)" > applic/tests.py
+
+sed -i -- 's/INSTALLED_APPS = \[/INSTALLED_APPS = \[\"applic\.apps\.ApplicConfig\"\,/g' foreign_keys/settings.py
+
+python manage.py makemigrations
+python manage.py migrate
+
+python manage.py test