* Update matcher engine for regex and extensions
Add support for matching over arbitrary Python predicate functions, and
arbitrary Python attribute getters. This will allow matching over regex
patterns, and allow supporting extension attributes.
The results of the Python predicate functions are cached, so that we don't
call the same predicate function twice for the same token. The extension
attributes are fetched into an array for each token in the doc. This
should minimise the performance impact of the new features.
We still need to wire up these features to the patterns, and test it
all.
* Work on wiring up extra attributes in matcher
* Work on tests for extra matcher attrs
* Add support for extension attrs to matcher
* Test extension attribute matching
* Work on implementing predicate-based match patterns
* Get predicates working for set membership
* Add test for set membership
* Make extensions+predicates work
* Test matcher extensions
* Cache predicate results better in Matcher
* Remove print statement in matcher test
* Use srsly to get key for predicates
* Auto-format tests with black
* Add flake8 config
* Tidy up and remove unused imports
* Fix redefinitions of test functions
* Replace orths_and_spaces with words and spaces
* Fix compatibility with pytest 4.0
* xfail test for now
Test was previously overwritten by following test due to naming conflict, so failure wasn't reported
* Unfail passing test
* Only use fixture via arguments
Fixes pytest 4.0 compatibility
## Description
Related issues: #2379 (should be fixed by separating model tests)
* **total execution time down from > 300 seconds to under 60 seconds** 🎉
* removed all model-specific tests that could only really be run manually anyway – those will now live in a separate test suite in the [`spacy-models`](https://github.com/explosion/spacy-models) repository and are already integrated into our new model training infrastructure
* changed all relative imports to absolute imports to prepare for moving the test suite from `/spacy/tests` to `/tests` (it'll now always test against the installed version)
* merged old regression tests into collections, e.g. `test_issue1001-1500.py` (about 90% of the regression tests are very short anyways)
* tidied up and rewrote existing tests wherever possible
### Todo
- [ ] move tests to `/tests` and adjust CI commands accordingly
- [x] move model test suite from internal repo to `spacy-models`
- [x] ~~investigate why `pipeline/test_textcat.py` is flakey~~
- [x] review old regression tests (leftover files) and see if they can be merged, simplified or deleted
- [ ] update documentation on how to run tests
### Types of change
enhancement, tests
## Checklist
<!--- Before you submit the PR, go over this checklist and make sure you can
tick off all the boxes. [] -> [x] -->
- [x] I have submitted the spaCy Contributor Agreement.
- [x] I ran the tests, and all new and existing tests passed.
- [ ] My changes don't require a change to the documentation, or if they do, I've added all required information.
