Cassette names:

- Should be meaningful so that it is obvious to you what test/function
they relate to. Meaningful names are important so that you can quickly
determine to what test file or test block a cassette belongs. Note that
vcr cannot check that your cassette names are meaningful.
- Should not be duplicated. Duplicated cassette names would lead to
a test using the wrong cassette.
- Should not have spaces. Spaces can lead to problems in using file paths.
- Should not include a file extension. vcr handles file extensions for
the user.
- Should not have illegal characters that can lead to problems in using
file paths: `/`, `?`, `<`, `>`, `\\`, `:`, `*`, `|`, and `\"`
- Should not have control characters, e.g., `\n`
- Should not have just dots, e.g., `.` or `..`
- Should not have Windows reserved words, e.g., `com1`
- Should not have trailing dots
- Should not be longer than 255 characters

`vcr::check_cassette_names()` is meant to be run during your tests, from a
`setup-pkgname.R` file inside the `tests/testthat` directory. It only
checks that cassette names are not duplicated. Note that if you do 
need to have duplicated cassette names you can do so by using the
`allowed_duplicates` parameter in `check_cassette_names()`. A helper function
`check_cassette_names()` runs inside [insert_cassette()] that checks
that cassettes do not have: spaces, file extensions, unaccepted
characters (slashes)
