Require usage of expect_s4_class(x, k) over expect_true(is(x, k))

testthat::expect_s4_class() exists specifically for testing the class of S4 objects. testthat::expect_true() can also be used for such tests, but it is better to use the tailored function instead.

Usage

expect_s4_class_linter()

See also

• linters for a complete list of linters available in lintr.

• expect_s3_class_linter()

Tags

best_practices, package_development, pkg_testthat

Examples

# will produce lints
lint(
  text = 'expect_true(is(x, "Matrix"))',
  linters = expect_s4_class_linter()
)
#> <text>:1:1: warning: [expect_s4_class_linter] expect_s4_class(x, k) is better than expect_true(is(x, k)). Note also expect_s3_class() available for testing S3 objects.
#> expect_true(is(x, "Matrix"))
#> ^~~~~~~~~~~~~~~~~~~~~~~~~~~~

# okay
lint(
  text = 'expect_s4_class(x, "Matrix")',
  linters = expect_s4_class_linter()
)
#> ℹ No lints found.