Run posthog-production CI in a way testing migration continuity

.github/workflows/ci-backend.yml

@@ -142,8 +142,8 @@ jobs:
                   touch frontend/dist/shared_dashboard.html
                   python manage.py test ee --testrunner="ee.clickhouse.clickhouse_test_runner.ClickhouseTestRunner"
 
-    multitenancy:
-        name: Django tests – posthog-production
+    cloud:
+        name: Django tests – Cloud
         runs-on: ubuntu-latest
 
         services:
@@ -169,11 +169,13 @@ jobs:
                   curl -L https://github.com/posthog/posthog-production/tarball/master | tar --strip-components=1 -xz --
                   mkdir deploy/
 
-            - uses: actions/checkout@v2
+            - name: Checkout master
+              uses: actions/checkout@v2
               with:
+                  ref: 'master'
                   path: 'deploy/'
 
-            - name: Link posthog-production
+            - name: Link posthog-production at master
               run: |
                   cp -r multi_tenancy deploy/
                   cp -r messaging deploy/
@@ -200,6 +202,29 @@ jobs:
                   python -m pip install freezegun
               if: steps.cache.outputs.cache-hit != 'true'
 
+            # The 2-step migration process (first master, then current branch) verifies that it'll always
+            # be possible to migrate to the new version without problems in production
+            - name: Migrate initially at master, then remove master deploy code
+              env:
+                  SECRET_KEY: '6b01eee4f945ca25045b5aab440b953461faf08693a9abbf1166dc7c6b9772da' # unsafe - for testing only
+                  DATABASE_URL: 'postgres://postgres:postgres@localhost:${{ job.services.postgres.ports[5432] }}/postgres'
+                  REDIS_URL: 'redis://localhost'
+              run: |
+                  python deploy/manage.py migrate
+                  rm -rf deploy
+
+            - name: Checkout current branch
+              uses: actions/checkout@v2
+              with:
+                  path: 'deploy/'
+
+            - name: Link posthog-production at current branch
+              run: |
+                  cp -r multi_tenancy deploy/
+                  cp -r messaging deploy/
+                  cat multi_tenancy_settings.py >> deploy/posthog/settings.py
+                  cat requirements.txt >> deploy/requirements.txt
+
             - name: Check migrations
               env:
                   SECRET_KEY: '6b01eee4f945ca25045b5aab440b953461faf08693a9abbf1166dc7c6b9772da' # unsafe - for testing only
@@ -208,6 +233,7 @@ jobs:
               run: |
                   cd deploy
                   python manage.py makemigrations --check --dry-run
+                  python manage.py migrate
 
             - name: Run posthog tests
               env:
@@ -235,9 +261,22 @@ jobs:
               run: |
                   cd deploy
                   python manage.py test multi_tenancy messaging --keepdb -v 2 --exclude-tag=skip_on_multitenancy
+            - name: Run EE tests
+              env:
+                  SECRET_KEY: '6b01eee4f945ca25045b5aab440b953461faf08693a9abbf1166dc7c6b9772da' # unsafe - for testing only
+                  DATABASE_URL: 'postgres://postgres:postgres@localhost:${{ job.services.postgres.ports[5432] }}/postgres'
+                  REDIS_URL: 'redis://localhost'
+                  PRIMARY_DB: 'clickhouse'
+                  CLICKHOUSE_HOST: 'localhost'
+                  CLICKHOUSE_DATABASE: 'posthog_test'
+                  CLICKHOUSE_SECURE: 'False'
+                  CLICKHOUSE_VERIFY: 'False'
+              run: |
+                  cd deploy
+                  python manage.py test ee --keepdb
 
     foss:
-        name: Django tests – posthog-foss
+        name: Django tests – FOSS
         runs-on: ubuntu-latest
 
         services: