test_that(
  "returns errors appropriately", {

    expect_condition(dates(list(filter = "date_range_ymd")))
    expect_condition(
      dates(list(filter = "date_range_ymd", "this is not a date"))
    )

  }
)

test_that(
  "correctly convert dates", {

    f <- "date_range_ymd"
    expect_identical(dates(list(filter = f, "2001")), "2001")
    expect_identical(dates(list(filter = f, 2001)), "2001")
    expect_identical(dates(list(filter = f, 2001L)), "2001")
    expect_identical(dates(list(filter = f, end = "2001")), "2001")
    expect_identical(dates(list(filter = f, end = 2001)), "2001")
    expect_identical(dates(list(filter = f, end = 2001L)), "2001")

    expect_identical(dates(list(filter = f, "2001-05")), "2001-05")
    expect_identical(dates(list(filter = f, end = "2001-05")), "2001-05")

    expect_identical(dates(list(filter = f, "2001-05-01")), "2001-05-01")
    expect_identical(dates(list(filter = f, end = "2001-05-01")), "2001-05-01")

    expect_identical(
      dates(list(filter = f, as.Date("2001-05-01"))), "2001-05-01"
    )
    expect_identical(
      dates(list(filter = f, end = as.Date("2001-05-01"))),
      "2001-05-01"
    )

    expect_identical(dates(list(filter = f, 2001, 2004)), "2001/2004")
    expect_identical(dates(list(filter = f, "2001", 2004)), "2001/2004")
    expect_identical(dates(list(filter = f, 2001L, 2004)), "2001/2004")
    expect_identical(dates(list(filter = f, 2001, "2004")), "2001/2004")

    expect_identical(
      dates(list(filter = f, "2001-05", "2002-06")), "2001-05/2002-06"
    )

    expect_identical(
      dates(list(filter = f, "2001", "2002-06")), "2001-01/2002-06"
    )
    expect_identical(
      dates(list(filter = f, "2001-05", "2003")), "2001-05/2003-12"
    )

    expect_identical(
      dates(list(filter = f, "2001-05-01", "2002-06-11")),
      "2001-05-01/2002-06-11"
    )
    expect_identical(
      dates(list(filter = f, "2001", "2002-06-11")), "2001-01-01/2002-06-11"
    )
    expect_identical(
      dates(list(filter = f, "2001-02", "2002-06-11")), "2001-02-01/2002-06-11"
    )
    expect_identical(
      dates(list(filter = f, "2001-05-01", "2002-06")), "2001-05-01/2002-06-30"
    )
    expect_identical(
      dates(list(filter = f, "2001-05-01", "2002")), "2001-05-01/2002-12-31"
    )
    expect_identical(
      dates(
        list(
          filter = f,
          structure(
            list(
              start = as.Date("2001-05-01"),
              .Data = as.difftime(609, units = "days")
            ),
            class = "Interval"
          )
        )
      ),
      "2001-05-01/2002-12-31"
    )

    f <- "date_range_ym"
    expect_identical(dates(list(filter = f, "2001")), "2001")
    expect_identical(dates(list(filter = f, 2001)), "2001")
    expect_identical(dates(list(filter = f, 2001L)), "2001")
    expect_identical(dates(list(filter = f, end = "2001")), "2001")
    expect_identical(dates(list(filter = f, end = 2001)), "2001")
    expect_identical(dates(list(filter = f, end = 2001L)), "2001")

    expect_identical(dates(list(filter = f, "2001-05")), "2001-05")
    expect_identical(dates(list(filter = f, end = "2001-05")), "2001-05")

    expect_identical(dates(list(filter = f, "2001-05-01")), "2001-05")
    expect_identical(dates(list(filter = f, end = "2001-05-01")), "2001-05")

    expect_identical(
      dates(list(filter = f, as.Date("2001-05-01"))), "2001-05"
    )
    expect_identical(
      dates(list(filter = f, end = as.Date("2001-05-01"))), "2001-05"
    )

    expect_identical(dates(list(filter = f, 2001, 2004)), "2001/2004")
    expect_identical(dates(list(filter = f, "2001", 2004)), "2001/2004")
    expect_identical(dates(list(filter = f, 2001L, 2004)), "2001/2004")
    expect_identical(dates(list(filter = f, 2001, "2004")), "2001/2004")

    expect_identical(
      dates(list(filter = f, "2001-05", "2002-06")), "2001-05/2002-06"
    )

    expect_identical(
      dates(list(filter = f, "2001", "2002-06")), "2001-01/2002-06"
    )
    expect_identical(
      dates(list(filter = f, "2001-05", "2003")), "2001-05/2003-12"
    )

    expect_identical(
      dates(list(filter = f, "2001-05-01", "2002-06-11")), "2001-05/2002-06"
    )
    expect_identical(
      dates(list(filter = f, "2001", "2002-06-11")), "2001-01/2002-06"
    )
    expect_identical(
      dates(list(filter = f, "2001-02", "2002-06-11")), "2001-02/2002-06"
    )
    expect_identical(
      dates(list(filter = f, "2001-05-01", "2002-06")), "2001-05/2002-06"
    )
    expect_identical(
      dates(list(filter = f, "2001-05-01", "2002")), "2001-05/2002-12"
    )

    expect_identical(dates(list(filter = "date_range_d", 1, 50)), "1/50")
    expect_identical(
      dates(list(filter = "date_range_md", "05-03", "06-01")), "503/601"
    )
    expect_identical(
      dates(list(filter = "last_import_date_min", 2001)), "2001"
    )
    expect_identical(
      dates(list(filter = "last_import_date_max", 2001)), "2001"
    )
    expect_identical(
      dates(list(filter = "first_import_date_min", 2001)), "2001"
    )
    expect_identical(
      dates(list(filter = "first_import_date_max", 2001)), "2001"
    )
  }
)