test_that("equals_na_linter skips allowed usages", {
  linter <- equals_na_linter()

  expect_no_lint("blah", linter)
  expect_no_lint("  blah", linter)
  expect_no_lint("  blah", linter)
  expect_no_lint("x == 'NA'", linter)
  expect_no_lint("x <- NA", linter)
  expect_no_lint("x <- NaN", linter)
  expect_no_lint("x <- NA_real_", linter)
  expect_no_lint("is.na(x)", linter)
  expect_no_lint("is.nan(x)", linter)
  expect_no_lint("x[!is.na(x)]", linter)

  # equals_na_linter should ignore strings and comments
  expect_no_lint("is.na(x) # do not flag x == NA if inside a comment", linter)
  expect_no_lint("lint_msg <- 'do not flag x == NA if inside a string'", linter)

  # nested NAs are okay
  expect_no_lint("x==f(1, ignore = NA)", linter)
})

skip_if_not_installed("tibble")
patrick::with_parameters_test_that(
  "equals_na_linter blocks disallowed usages for all combinations of operators and types of NAs",
  expect_lint(
    paste("x", operation, type_na),
    "Use is.na for comparisons to NA (not == or !=)",
    NULL
  ),
  .cases = tibble::tribble(
    ~.test_name                , ~operation , ~type_na        ,
    "equality, logical NA"     , "=="       , NA              ,
    "equality, integer NA"     , "=="       , "NA_integer_"   ,
    "equality, real NA"        , "=="       , "NA_real_"      ,
    "equality, complex NA"     , "=="       , "NA_complex_"   ,
    "equality, character NA"   , "=="       , "NA_character_" ,
    "inequality, logical NA"   , "!="       , NA              ,
    "inequality, integer NA"   , "!="       , "NA_integer_"   ,
    "inequality, real NA"      , "!="       , "NA_real_"      ,
    "inequality, complex NA"   , "!="       , "NA_complex_"   ,
    "inequality, character NA" , "!="       , "NA_character_"
  )
)

test_that("equals_na_linter blocks disallowed usages in edge cases", {
  linter <- equals_na_linter()
  lint_msg <- "Use is.na for comparisons to NA (not == or !=)"

  # missing spaces around operators
  expect_lint("x==NA", lint_msg, linter)
  expect_lint("x!=NA", lint_msg, linter)

  # order doesn't matter
  expect_lint("NA == x", lint_msg, linter)

  # correct line number for multiline code
  expect_lint("x ==\nNA", lint_msg, linter)
})