tests/testthat/test-seq_linter.R

In jimhester/lintr: A 'Linter' for R Code

test_that("other : expressions are fine", {
  linter <- seq_linter()
  expect_lint("1:10", NULL, linter)
  expect_lint("2:length(x)", NULL, linter)
  expect_lint("1:(length(x) || 1)", NULL, linter)
})

test_that("seq_len(...) or seq_along(...) expressions are fine", {
  linter <- seq_linter()

  expect_lint("seq_len(x)", NULL, linter)
  expect_lint("seq_along(x)", NULL, linter)

  expect_lint("seq(2, length(x))", NULL, linter)
  expect_lint("seq(length(x), 2)", NULL, linter)
})

test_that("finds seq(...) expressions", {
  linter <- seq_linter()
  lint_msg <- function(want, got) rex::rex("Use ", want, " instead of ", got)

  expect_lint(
    "seq(length(x))",
    lint_msg("seq_along(...)", "seq(length(...))"),
    linter
  )

  expect_lint(
    "seq(nrow(x))",
    lint_msg("seq_len(nrow(...))", "seq(nrow(...))"),
    linter
  )

  expect_lint(
    "rev(seq(length(x)))",
    lint_msg("seq_along(...)", "seq(length(...))"),
    linter
  )

  expect_lint(
    "rev(seq(nrow(x)))",
    lint_msg("seq_len(nrow(...))", "seq(nrow(...))"),
    linter
  )
})

test_that("finds 1:length(...) expressions", {
  linter <- seq_linter()
  lint_msg <- function(want, got) rex::rex("Use ", want, " instead of ", got)

  expect_lint(
    "1:length(x)",
    lint_msg("seq_along(...)", "1:length(...)"),
    linter
  )

  expect_lint(
    "1:nrow(x)",
    lint_msg("seq_len(nrow(...))", "1:nrow(...)"),
    linter
  )

  expect_lint(
    "1:ncol(x)",
    lint_msg("seq_len(ncol(...))", "1:ncol(...)"),
    linter
  )

  expect_lint(
    "1:NROW(x)",
    lint_msg("seq_len(NROW(...))", "1:NROW(...)"),
    linter
  )

  expect_lint(
    "1:NCOL(x)",
    lint_msg("seq_len(NCOL(...))", "1:NCOL(...)"),
    linter
  )

  expect_lint(
    "1:dim(x)[1L]",
    lint_msg("seq_len(dim(...)[1L])", "1:dim(...)[1L]"),
    linter
  )

  expect_lint(
    "1L:dim(x)[[1]]",
    rex::rex("Use seq_len", anything, "dim(...)"),
    linter
  )

  expect_lint(
    "mutate(x, .id = 1:n())",
    lint_msg("seq_len(n())", "1:n(),"),
    linter
  )

  expect_lint(
    "x[, .id := 1:.N]",
    lint_msg("seq_len(.N)", "1:.N,"),
    linter
  )
})

test_that("1L is also bad", {
  expect_lint(
    "1L:length(x)",
    rex::rex("seq_along", anything, "1L:length(...)"),
    seq_linter()
  )
})

test_that("reverse seq is ok", {
  linter <- seq_linter()
  expect_lint("rev(seq_along(x))", NULL, linter)
  expect_lint("rev(seq_len(nrow(x)))", NULL, linter)

  expect_lint(
    "length(x):1",
    rex::rex("rev(seq_along(...))", anything, "length(...):1"),
    linter
  )
})

test_that("Message vectorization works for multiple lints", {
  linter <- seq_linter()

  expect_lint(
    trim_some("{
      1:length(x)
      1:nrow(y)
    }"),
    list(
      list(rex::rex("seq_along(...)", anything, "1:length(...)"), line_number = 2L),
      list(rex::rex("seq_len(nrow(...))", anything, "1:nrow(...)"), line_number = 3L)
    ),
    linter
  )

  expect_lint(
    trim_some("{
      seq(length(x))
      1:nrow(y)
    }"),
    list(
      list(rex::rex("seq_along(...)", anything, "seq(length(...))"), line_number = 2L),
      list(rex::rex("seq_len(nrow(...))", anything, "1:nrow(...)"), line_number = 3L)
    ),
    linter
  )

  expect_lint(
    trim_some("{
      seq(length(x))
      seq(nrow(y))
    }"),
    list(
      list(rex::rex("seq_along(...)", anything, "seq(length(...))"), line_number = 2L),
      list(rex::rex("seq_len(nrow(...))", anything, "seq(nrow(...))"), line_number = 3L)
    ),
    linter
  )

  expect_lint(
    trim_some("{
      1:NROW(x)
      seq(NCOL(y))
    }"),
    list(
      list(rex::rex("seq_len(NROW(...))", anything, "1:NROW(...)"), line_number = 2L),
      list(rex::rex("seq_len(NCOL(...))", anything, "seq(NCOL(...))"), line_number = 3L)
    ),
    linter
  )
})

test_that("Message recommends rev() correctly", {
  linter <- seq_linter()

  expect_lint(".N:1", rex::rex("Use rev(seq_len(.N))"), linter)
  expect_lint("n():1", rex::rex("Use rev(seq_len(n()))"), linter)
  expect_lint("nrow(x):1", rex::rex("Use rev(seq_len(nrow(...)))"), linter)
  expect_lint("length(x):1", rex::rex("Use rev(seq_along(...))"), linter)
})