Tests

add hypothesis test for ExtendedData, refactor ExtendedData #1606

Job	Run time
doctest-lxml (3.12)	41s
cpython-lxml (3.8)	2m 30s
cpython (3.8)	13s
Build & inspect our package.	19s
cpython-lxml (3.9)	2m 1s
cpython (3.9)	13s
cpython-lxml (3.10)	1m 57s
pypy (pypy-3.8)	32s
cpython (3.10)	15s
cpython-lxml (3.11)	2m 12s
pypy (pypy-3.9)	32s
static-tests (3.12)	29s
cpython-lxml (3.12)	2m 46s
cpython (3.11)	18s
pypy (pypy-3.10)	30s
cpython-lxml (3.13)	3m 10s
cpython (3.12)	12s
cpython (3.13)	21s
cpython (3.14-dev)	25s
Test install on TestPyPI	0s
Publish to PyPI on push to main	0s
	19m 36s

Provide feedback