tests/testthat/test-capture.R

In rex: Friendly Regular Expressions

context("capture")
test_that("matches basic characters", {
  x <- "text"
  re <- rex(capture(x))

  expect_equal(re, regex("(text)"))

  expect_true(grepl(re, x))

  expect_equal(gsub(re, "\\1", x), x)

  expect_equal(gsub(re, "replacement", x), "replacement")
})

test_that("escapes special characters", {
  x <- "^[x$\\"
  re <- rex(capture(x))

  expect_equal(re, regex("(\\^\\[x\\$\\\\)"))

  expect_true(grepl(re, x))

  expect_equal(gsub(re, "\\1", x), x)

  expect_equal(gsub(re, "replacement", x), "replacement")
})

test_that("examples work", {
 re <- rex(
   # first quotation mark
   capture(quote),

   # match all non-matching quotation marks
   zero_or_more(except(capture_group(1))),

   # end quotation mark (matches first)
   capture_group(1)
 )

 expect_equal(re, regex("(['\"])(?:[^\\g{1}])*\\g{1}"))

 lapply(c("\"\"", "\"'\"", "\"arst\"", "''", "'arst'", "'\"'"),
   function(x) {
     expect_true(grepl(re, x, perl = TRUE), info=x)
   }
 )

 lapply(c("'a", "'asr\""), function(x) {
    expect_false(grepl(re, x, perl = TRUE), info = x)
 })

})

context("named capture")
test_that("examples work", {
  re <- rex(
    capture(name = "fruit", or("apple", "orange")),
    "=",
    capture_group("fruit")
    )

  expect_true(grepl(re, "apple=apple", perl=TRUE))
  expect_true(grepl(re, "orange=orange", perl=TRUE))
  expect_false(grepl(re, "apple=orange", perl=TRUE))
})