Migration of runtime tests to hypothesis based property testing

[abelcheung]

This issue tracks the progress of migrating existing runtime tests to hypothesis:

• [ ] test_elem_class_lookup.py
• [ ] test_iterparse.py
  • Depends on whether XML/HTMLPullParser options are tested or not (currently not)
• [x] test_attrib.py (ec203cf76b2b06a3d3968bb97993674d3058e870)
• [x] test_errorlog.py (f07ad28bda9c876240b0f1fe3a96b143c837d1a2)
• [x] test_etree_element.py
  • [x] Magic methods and basic mixin methods (72d73806f148039bd57c3e71652c8d123f3d9c87)
  • [x] Content only elements (81eac99847c610bfc7c8a2fc77f380f469eb1862)
  • [x] Attribute access methods (fed3bb8c7327ca5294589681352ff9e61b3da905)
  • [x] find* family methods. (c2c5bf8d008d0c88547fbd2f4ad097eb9e4c95f8)
  • [x] add* family methods (e02626e5e9d5d198d0eea5085d3de3b1a8ee6235)
  • [x] iter* family methods (4b078ca7f9a48e2ca6ec4441b60e799898c828aa)
• [x] html/test_beautifulsoup.py (cfe2af58ce0f0a4cf369ec50f8b80140fd91b125)
• [x] html/test_html5lib.py (e2c3ebd0165a7a5ce536805f7f264899d63ca7e5)
• [x] html/test_link_func.py (bde5482b59d7bf0e5beb2832c37056ac6af45067)

Following files don't need converting:

• test_constants.py
• test_xinclude.py
• test_etree_element.py get*() family methods