Test Incorporation

Inspired by the recent incidents of change-in-some-scripts resulting in the breaking of other scripts and back-and-forth reversing the change (see https://github.com/acl-org/acl-anthology/commit/8500a12307de69be9b799308dbdf7e57841d9537#r67683715, https://github.com/acl-org/acl-anthology/pull/1836/commits/50531e243ea5b9842cb359c75a2f8851a1b42002 and discussion in https://github.com/acl-org/acl-anthology/pull/1833#issuecomment-1055813438), it seems like we could really use some tests.

While trying to use `pytest` package for the tests, I encountered a problem. The version of`texsoup` package we currently use is ancient and isn't compatible with `pytest`. https://github.com/acl-org/acl-anthology/blob/56145deed72d4b3a43788e5ea7bfe200b12cd2d8/bin/requirements.txt#L18

Upgradinig the `texsoup` version will solve the problem and I think is the best solution (unless for some reason we have to work with the ancient version). Before I dive into changing the code (https://github.com/acl-org/acl-anthology/blob/master/bin/anthology/texmath.py):

- I'm not terribly familiar with texsoup so upgrading the codebase isn't trivia. Any insights/tips that could speed up the process are greatly appreciated!
- Any other suggestions/solutions?

@mjpost @mbollmann

Review the dependency entry in bin/requirements.txt and the TexSoup integration in bin/anthology/texmath.py. Start by checking whether the current TexSoup version is compatible with pytest, then identify the scripts that need coverage from the linked incident context. Done means pytest can be used and tests cover the changes without breaking those scripts.

Do mô hình lập chỉ mục viết ra từ nội dung của issue.