test the reader with the writer

[MichaelPFrey]

Description

I think that currently, there are only few good tests for the reader. (see for e.g. #2700 where the reader and writer where modified, but only the writer is actually covered by a test)

Creating and adding artifacts (docx and odt) is not ideal, as they are hard to verify and will contain random other artifacts.

By dynamically creating the test-file using the writer and reading it back in with the reader, we can simply test the reader against the writer.

In general, a WYSWYG word processor is assumed to read and save files without loosing anything. For a project like PHPOffice, the focus is stronger on the writer then the reader. With this setup, it is a lot easier to work on the reader, as a test driven development purely in PHP gets enabled - the need to use a word processor for verification gets significantly reduced.

There is also simply charm in self testing, as a simple to read test makes a literal "end to end" test, covering a lot of complex code with a few lines of simple code.

Fixes # (issue)

Checklist:

• My CI is 🟢
• I have covered by unit tests my new code (check build/coverage for coverage report)
• I have updated the documentation to describe the changes
• I have updated the changelog

This are literal test. They do not effect the production code. So the checklist does not directly apply.

[coveralls]

coverage: 96.765% (+0.008%) from 96.757%
when pulling a902537 on MichaelPFrey:mfr-2025-02-09
into 5c84adf on PHPOffice:master.

[Progi1984]

@MichaelPFrey Could you update the changelog, please ?

[Progi1984]

@MichaelPFrey Thank you for your contribution 🥳