diff --git a/Dockerfile b/Dockerfile
index 978b23e..6897a36 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -2,6 +2,8 @@
 FROM python:3.7-slim-bullseye
 
 RUN python -m venv /app
+# Make sure a 'db.sqlite' file exists in '.' if you want to launch the container
+# without referencing an external database.
 COPY . /app/reps/djaodjin-deployutils
 WORKDIR /app/reps/djaodjin-deployutils
 RUN /app/bin/pip install -r testsite/requirements.txt
diff --git a/testsite/wsgi.py b/testsite/wsgi.py
index fc8123e..d604d78 100644
--- a/testsite/wsgi.py
+++ b/testsite/wsgi.py
@@ -18,8 +18,10 @@ def save_coverage():
 if os.getenv('DJANGO_COVERAGE'):
     import atexit, sys
     import coverage
-    cov = coverage.coverage(data_file=os.path.join(os.getenv('DJANGO_COVERAGE'),
-        ".coverage.%d" % os.getpid()))
+    data_file=os.path.join(os.getenv('DJANGO_COVERAGE'),
+        ".coverage.%d" % os.getpid())
+    cov = coverage.coverage(data_file=data_file)
+    sys.stderr.write("start recording coverage in %s\n" % str(data_file))
     cov.start()
     atexit.register(save_coverage)
     try: