Require usage of expect_false(.) over expect_true(!.)Source:
testthat::expect_false() exists specifically for testing that an output is
testthat::expect_true() can also be used for such tests by
negating the output, but it is better to use the tailored function instead.
The reverse is also true -- use
expect_false(A) instead of
linters for a complete list of linters available in lintr.