Require usage of expect_gt(x, y) over expect_true(x > y) (and similar)

testthat::expect_gt(), testthat::expect_gte(), testthat::expect_lt(), testthat::expect_lte(), and testthat::expect_equal() exist specifically for testing comparisons between two objects. testthat::expect_true() can also be used for such tests, but it is better to use the tailored function instead.

Usage

expect_comparison_linter()

See also

linters for a complete list of linters available in lintr.

Tags

best_practices, package_development, pkg_testthat

Examples

# will produce lints
lint(
  text = "expect_true(x > y)",
  linters = expect_comparison_linter()
)
#> <text>:1:1: warning: [expect_comparison_linter] expect_gt(x, y) is better than expect_true(x > y).
#> expect_true(x > y)
#> ^~~~~~~~~~~~~~~~~~

lint(
  text = "expect_true(x <= y)",
  linters = expect_comparison_linter()
)
#> <text>:1:1: warning: [expect_comparison_linter] expect_lte(x, y) is better than expect_true(x <= y).
#> expect_true(x <= y)
#> ^~~~~~~~~~~~~~~~~~~

lint(
  text = "expect_true(x == (y == 2))",
  linters = expect_comparison_linter()
)
#> <text>:1:1: warning: [expect_comparison_linter] expect_identical(x, y) is better than expect_true(x == y).
#> expect_true(x == (y == 2))
#> ^~~~~~~~~~~~~~~~~~~~~~~~~~

# okay
lint(
  text = "expect_gt(x, y)",
  linters = expect_comparison_linter()
)
#> ℹ No lints found.

lint(
  text = "expect_lte(x, y)",
  linters = expect_comparison_linter()
)
#> ℹ No lints found.

lint(
  text = "expect_identical(x, y == 2)",
  linters = expect_comparison_linter()
)
#> ℹ No lints found.

lint(
  text = "expect_true(x < y | x > y^2)",
  linters = expect_comparison_linter()
)
#> ℹ No lints found.