Some tests, and some functionality, will not be enabled unless a full set of 32-bit character encodings are available through Python.
The package 'iconvcodec' provides the necessary codecs, if your underlying operating system supports them. Its web page is at http://cjkpython.i18n.org/#iconvcodec, and a range of packages are provided.
Python 2.3.x is required, for its Unicode support.
To run with Docker: docker build -t feedvalidator . docker run -p 8080:80 feedvalidator