test_that("Returns correct quarter in correct format", {
  expect_equal(
    "Jan-Mar 2018",
    qtr(date = lubridate::dmy(25032018), format = "short")
  )
  expect_equal(
    "January to March 2018",
    qtr(date = lubridate::dmy(25032018), format = "long")
  )
  expect_equal(
    "Oct-Dec 2018",
    qtr(date = lubridate::dmy(15102018), format = "short")
  )
  expect_equal(
    "October to December 2018",
    qtr(date = lubridate::dmy(15102018), format = "long")
  )
  expect_equal(
    "Sep 2018",
    qtr_end(date = lubridate::dmy(03072018), format = "short")
  )
  expect_equal(
    "September 2018",
    qtr_end(date = lubridate::dmy(03072018), format = "long")
  )
  expect_equal(
    "Dec 2018",
    qtr_end(date = lubridate::dmy(15112018), format = "short")
  )
  expect_equal(
    "December 2018",
    qtr_end(date = lubridate::dmy(15112018), format = "long")
  )
  expect_equal(
    "Oct-Dec 1998",
    qtr_next(date = lubridate::dmy(02091998), format = "short")
  )
  expect_equal(
    "October to December 1998",
    qtr_next(date = lubridate::dmy(02091998), format = "long")
  )
  expect_equal(
    "Jan-Mar 2006",
    qtr_next(date = lubridate::dmy(14112005), format = "short")
  )
  expect_equal(
    "January to March 2006",
    qtr_next(date = lubridate::dmy(14112005), format = "long")
  )
  expect_equal(
    "Oct-Dec 2017",
    qtr_prev(date = lubridate::dmy(25032018), format = "short")
  )
  expect_equal(
    "October to December 2017",
    qtr_prev(date = lubridate::dmy(25032018), format = "long")
  )
  expect_equal(
    "Jul-Sep 2018",
    qtr_prev(date = lubridate::dmy(15102018), format = "short")
  )
  expect_equal(
    "July to September 2018",
    qtr_prev(date = lubridate::dmy(15102018), format = "long")
  )
})

test_that("Errors if the input date is not in date format", {
  expect_error(qtr(date = "2018-03-25", format = "short"))
  expect_error(qtr_end(date = as.factor("2018-03-25"), format = "long"))
  expect_error(qtr_next(date = NULL, format = "short"))
  expect_error(qtr_prev(
    date = as.numeric(lubridate::dmy(25032018)),
    format = "long"
  ))
})