docker/test: improve setup

`make test` now automatically forces a rebuild. Also passing `keepdb=true` runs
the test suite with `--keepdb` which is useful when repeatedly running tests.

Makefile

@@ -1,8 +1,12 @@
 build-test:
 	cd docker/test; docker compose build
 
-test:
-	touch docker/test/coverage.xml
-	chmod 666 docker/test/coverage.xml
+test: build-test
+	mkdir -p docker/test/htmlcov
+	chmod 777 docker/test/htmlcov
+ifeq ($(keepdb), true)
+	cd docker/test; DJANGO_TEST_KEEPDB=1 docker compose up --abort-on-container-exit
+else
 	cd docker/test; docker compose up --abort-on-container-exit
-	sed -i 's/\/app\/jdav_web/jdav_web/g' docker/test/coverage.xml
+endif
+	echo "Generated coverage report. To read it, point your browser to:\n\nfile://$$(pwd)/docker/test/htmlcov/index.html"

docker/test/docker-compose.yaml

@@ -7,6 +7,8 @@ services:
             context: ./../../
             dockerfile: docker/test/Dockerfile
         env_file: docker.env
+        environment:
+          - DJANGO_TEST_KEEPDB=$DJANGO_TEST_KEEPDB
         depends_on:
           - redis
           - cache

docker/test/entrypoint-master.sh

@@ -38,5 +38,9 @@ fi
 
 cd jdav_web
 
-coverage run manage.py test startpage finance members contrib logindata mailer material -v 2 --noinput
+if [[ "$DJANGO_TEST_KEEPDB" == 1 ]]; then
+    coverage run manage.py test startpage finance members contrib logindata mailer material -v 2 --noinput --keepdb
+else
+    coverage run manage.py test startpage finance members contrib logindata mailer material -v 2 --noinput
+fi
 coverage html