try this

Dockerfile

@@ -116,6 +116,8 @@ ENV PYTHONPYCACHEPREFIX=/tmp/pycache
 # Disable pytest's .pytest_cache directory (also writes to /app, which is root-owned).
 # Only has an effect when running tests inside the container.
 ENV PYTEST_ADDOPTS="-p no:cacheprovider"
+# Redirect test logs to the datastore (writable) instead of /app/tests/logs (read-only in container).
+ENV TEST_LOG_DIR=/datastore/test_logs
 
 # Re #80, sets SECLEVEL=1 in openssl.conf to allow monitoring sites with weak/old cipher suites
 RUN sed -i 's/^CipherString = .*/CipherString = DEFAULT@SECLEVEL=1/' /etc/ssl/openssl.cnf

changedetectionio/tests/conftest.py

@@ -39,8 +39,9 @@ def per_test_log_file(request):
     """Create a separate log file for each test function with pytest output."""
     import re
 
-    # Create logs directory if it doesn't exist
-    log_dir = os.path.join(os.path.dirname(__file__), "logs")
+    # Create logs directory if it doesn't exist.
+    # TEST_LOG_DIR can be overridden e.g. to a writable path when /app is read-only (Docker).
+    log_dir = os.environ.get('TEST_LOG_DIR', os.path.join(os.path.dirname(__file__), "logs"))
     os.makedirs(log_dir, exist_ok=True)
 
     # Generate log filename from test name and worker ID (for parallel runs)