Problem:
13748512f6#15610 The no-colors codepath of the nvim.lua test output
handler does not handle nil, leading to weird symptoms if e.g. a test
has a syntax error:
test/busted/outputHandlers/nvim.lua:105: attempt to concatenate a nil value
Solution:
Coerce to string in no-colors handler.
Problem
-------
Because test/busted/outputHandlers/nvim.lua doesn't know if it's running
in a terminal (no "isatty" equivalent), it outputs color codes in CI
logs and local tooling that runs the tests in a pipe:
[1m[33m[ SKIPPED ][0m[0m [36m
This is just noise, hard for humans to read.
Solution
--------
Disable the color codes. If we later find a clever way to detect
a terminal in nvim.lua, we might consider re-enabling colors, but that
would still affect the CI build logs...
* tests: move "busted" dir to "test"
It is used for outputHandlers only, and clearly belongs to the tests.
Use the full module name with the `-o` option to `busted` then for
clarity.
* luacheck
* test/busted/outputHandlers/TAP.lua: use/extend upstream
