Specifically, functions that are run in the context of the test runner
are put in module `test/testutil.lua` while the functions that are run
in the context of the test session are put in
`test/functional/testnvim.lua`.
Closes https://github.com/neovim/neovim/issues/27004.
Dispense with the FuncUndefined/CmdUndefined quasi-optimization.
If there are no rplugins, plugin/rplugin.vim takes less than 1ms.
Closes#5821Closes#6250
Helped-by: Qiming zhao <chemzqm@gmail.com>
It is otherwise impossible to determine which test failed sanitizer/valgrind
check. test/functional/helpers.lua module return was changed so that tests which
do not provide after_each function to get new check will automatically fail.