Integrity check for DIFF mode (#1245)

This test applies 2-3 months of weekly updates on the `europe/monaco` extract from [Geofabrik](http://download.geofabrik.de/europe/).

It is worth noting that the contents of the updates may vary, and some SQL update flows may not be tested if the relevant changes did not occur during that period.

Resolves #1226

.github/workflows/integrity.yml

@@ -36,3 +36,36 @@ jobs:
         run: |
           export TEST_MODE=yes
           make generate-devdoc
+
+      - name: Run quickstart and update in DIFF mode
+        env:
+          area: europe/monaco
+          QUIET: 1
+        run: |
+          echo MIN_ZOOM=0 >> .env
+          echo MAX_ZOOM=14 >> .env
+          echo DIFF_MODE=true >> .env
+          # Cleanup
+          rm -fr data build cache
+          # Create data/$area.repl.json
+          make download-geofabrik area=$area
+          # Download 2+ month old data
+          export old_date=$(date --date="$(date +%Y-%m-15) -2 month" +'%y%m01')
+          echo Downloading $old_date extract of $area
+          docker-compose run --rm --user=$(id -u):$(id -g) openmaptiles-tools sh -c "wget -O data/$area.osm.pbf http://download.geofabrik.de/$area-$old_date.osm.pbf"
+          # Initial import and tile generation
+          ./quickstart.sh $area
+          sleep 2
+          echo Downloading updates
+          # Loop to recover from potential "ERROR 429: Too Many Requests"
+          docker-compose run --rm --user=$(id -u):$(id -g) openmaptiles-tools sh -c "
+            while ! osmupdate --keep-tempfiles --base-url=$(sed -n 's/ *\"replication_url\": //p' data/$area.repl.json) data/$area.osm.pbf data/changes.osc.gz ; do 
+              sleep 2;
+              echo Sleeping...;
+              sleep 630;
+            done"
+          echo Downloading updates completed
+          echo Importing updates
+          make import-diff
+          echo Generating new tiles
+          make generate-tiles-pg