Require usage of expect_length(x, n) over expect_equal(length(x), n)

testthat::expect_length() exists specifically for testing the length() of an object. testthat::expect_equal() can also be used for such tests, but it is better to use the tailored function instead.

Usage

expect_length_linter()

See also

linters for a complete list of linters available in lintr.

Tags

best_practices, package_development, pkg_testthat, readability

Examples

# will produce lints
lint(
  text = "expect_equal(length(x), 2L)",
  linters = expect_length_linter()
)
#> <text>:1:1: warning: [expect_length_linter] expect_length(x, n) is better than expect_equal(length(x), n)
#> expect_equal(length(x), 2L)
#> ^~~~~~~~~~~~~~~~~~~~~~~~~~~

# okay
lint(
  text = "expect_length(x, 2L)",
  linters = expect_length_linter()
)
#> ℹ No lints found.