Allows to explicitly select a backend for the unit tests.
Currently supported are "testthat"
and "tinytest"
.
The respective package must be installed and are loaded (but not attached).
If this function is not explicitly called, defaults to "testthat"
unless
the "tinytest"
's namespace is loaded.
register_test_backend(name)
NULL
(invisibly).
[character(1)
]
"testthat"
or "tinytest"
.