# testing calculate_test_date() --------------------------------------------

test_that("start_date is correct format", {
  expect_error(
    calculate_test_date(2023 - 01 - 01),
    class = "pregnancy_error_class"
  )
})

test_that("start_date accepts character dates", {
  expect_equal(calculate_test_date("2023-01-31"), as.Date("2023-02-28"))
})

test_that("start_type matches arg", {
  start_date <- as.Date("2023-01-31")
  expect_error(
    calculate_test_date(start_date, start_type = "hello"),
    "must be one of"
  )
})

test_that("cycle is allowed value", {
  start_date <- as.Date("2023-01-31")
  expect_error(
    calculate_test_date(start_date, cycle = "28"),
    class = "pregnancy_error_class_or_length"
  )
  expect_error(
    calculate_test_date(start_date, cycle = 27:28),
    class = "pregnancy_error_class_or_length"
  )
  expect_error(
    calculate_test_date(start_date, cycle = NULL),
    class = "pregnancy_error_class_or_length"
  )
  expect_error(
    calculate_test_date(start_date, cycle = 19),
    class = "pregnancy_error_value"
  )
  expect_error(
    calculate_test_date(start_date, cycle = 45),
    class = "pregnancy_error_value"
  )
  expect_error(
    calculate_test_date(start_date, cycle = 27.5),
    class = "pregnancy_error_value"
  )
})

test_that("correct test date for each start type", {
  start_date <- as.Date("2023-01-31")
  expect_equal(calculate_test_date(start_date), as.Date("2023-02-28"))
  expect_equal(
    calculate_test_date(start_date, "conception"),
    as.Date("2023-02-14")
  )
  expect_equal(
    calculate_test_date(start_date, "transfer_day_3"),
    as.Date("2023-02-11")
  )
  expect_equal(
    calculate_test_date(start_date, "transfer_day_5"),
    as.Date("2023-02-09")
  )
  expect_equal(
    calculate_test_date(start_date, "transfer_day_6"),
    as.Date("2023-02-08")
  )
})

test_that("correct output for test_type = 'blood'", {
  start_date <- as.Date("2023-01-31")
  expect_equal(
    calculate_test_date(start_date, test_type = "blood"),
    as.Date("2023-02-26")
  )
})

test_that("test date for LMP adjusts with cycle", {
  start_date <- as.Date("2023-01-31")
  expect_equal(
    calculate_test_date(start_date, cycle = 27),
    as.Date("2023-02-27")
  )
  expect_equal(
    calculate_test_date(start_date, cycle = 29),
    as.Date("2023-03-01")
  )
})

test_that("calculate_test_date message", {
  start_date <- as.Date("2023-01-31")
  expect_snapshot(calculate_test_date(start_date))
})