Update README.md

Author: cfedermann

README.md

@@ -22,3 +22,21 @@ In your `.github/workflows/main.yml`, set environment variable `PYLINT_THRESHOLD
 You can drop the `env:` section in your `main.yml` file if you want to use the default value `9`.
 
 Set `BLACK_LINE_MAXLEN` to the desired max line length.
+
+In your local repo, it may be useful to add a `validation.sh` script to allow local testing before the GitHub action is run on the server. The following is an example used in a GitHub codespace (where `./venv/` stores the virtual environment):
+
+    #!/bin/sh -e
+
+    pip install black mypy pylint-fail-under reorder-python-imports safety
+    pip install -r requirements.txt
+
+    export PYLINT_THRESHOLD=8
+    export BLACK_LINE_MAXLEN=100
+
+    black -S -l $BLACK_LINE_MAXLEN --check .
+    find . -name "*.py" -not -path "./.venv/*" | xargs mypy
+    find . -name "*.py" -not -path "./.venv/*" | xargs pylint-fail-under --fail_under $PYLINT_THRESHOLD
+    find . -name "*.py" -not -path "./.venv/*" | xargs reorder-python-imports --diff-only
+    cat requirements.txt | safety check --stdin
+    
+Note that this should match `entrypoint.sh` but you are free to ignore local folders (such as `./.venv/`) if they exist in your dev environment.