data_dir <- file.path("..", "testdata")
tempfile_nc <- function() {
  tempfile_helper("extract.level_")
}

########## default input ##########
file_out <- tempfile_nc()
extract.level("SIS", file.path(data_dir, "ex_extract.level.nc"), file_out)
file <- nc_open(file_out)

test_that("data is correct", {
  actual <- ncvar_get(file)

  expected_data <- c(seq(250, 258), seq(254, 262))
  expected <- array(expected_data, dim = c(3, 3, 2))

  expect_equivalent(actual, expected)
})

test_that("variable attributes are correct", {
  actual <- ncatt_get(file, "SIS", "units")$value
  expect_equal(actual, "W m-2")

  actual <- ncatt_get(file, "SIS", "_FillValue")$value
  expect_equal(actual, -999)

  actual <- ncatt_get(file, "SIS", "standard_name")$value
  expect_equal(actual, "SIS_standard")

  actual <- ncatt_get(file, "SIS", "long_name")$value
  expect_equal(actual, "Surface Incoming Shortwave Radiation")

  actual <- ncatt_get(file, "SIS", "missing_value")$value
  expect_equal(actual, 0)
})

test_that("attributes are correct", {
  actual <- ncatt_get(file, "lon", "units")$value
  expect_equal(actual, "degrees_east")

  actual <- ncatt_get(file, "lon", "long_name")$value
  expect_equal(actual, "longitude")

  actual <- ncatt_get(file, "lon", "standard_name")$value
  expect_equal(actual, "longitude")

  actual <- ncatt_get(file, "lon", "axis")$value
  expect_equal(actual, "X")

  actual <- ncatt_get(file, "lat", "units")$value
  expect_equal(actual, "degrees_north")

  actual <- ncatt_get(file, "lat", "long_name")$value
  expect_equal(actual, "latitude")

  actual <- ncatt_get(file, "lat", "standard_name")$value
  expect_equal(actual, "latitude")

  actual <- ncatt_get(file, "lat", "axis")$value
  expect_equal(actual, "Y")

  actual <- ncatt_get(file, "time", "units")$value
  expect_equal(actual, "hours since 1983-01-01 00:00:00")

  actual <- ncatt_get(file, "time", "long_name")$value
  expect_equal(actual, "time")

  actual <- ncatt_get(file, "time", "standard_name")$value
  expect_equal(actual, "time")

  actual <- ncatt_get(file, "time", "calendar")$value
  expect_equal(actual, "standard")

  actual <- ncatt_get(file, "SIS", "standard_name")$value
  expect_equal(actual, "SIS_standard")

  actual <- ncatt_get(file, "SIS", "long_name")$value
  expect_equal(actual, "Surface Incoming Shortwave Radiation")

  actual <- ncatt_get(file, "SIS", "units")$value
  expect_equal(actual, "W m-2")

  actual <- ncatt_get(file, "SIS", "_FillValue")$value
  expect_equal(actual, -999)

  actual <- ncatt_get(file, "SIS", "cmsaf_info")$value
  expect_equal(actual, "cmsafops::extract.level for variable SIS and level 1")

  global_attr <- ncatt_get(file, 0)
  expect_equal(length(global_attr), 1)

  actual <- names(global_attr[1])
  expect_equal(actual, "Info")

  actual <- global_attr[[1]]
  expect_equal(actual, "Created with the CM SAF R Toolbox.")
})

test_that("coordinates are correct", {
  actual <- ncvar_get(file, "lon")
  expect_identical(actual, array(seq(5, 6, 0.5)))

  actual <- ncvar_get(file, "lat")
  expect_identical(actual, array(seq(45, 46, 0.5)))

  actual <- ncvar_get(file, "time")
  expect_equal(actual, array(c(149016, 149760)))
})

nc_close(file)

########## output ncdf version 4 ##########
file_out <- tempfile_nc()
extract.level("SIS", file.path(data_dir, "ex_extract.level.nc"),
              file_out, nc34 = 4)
file <- nc_open(file_out)

test_that("data is correct", {
  actual <- ncvar_get(file)

  expected_data <- c(seq(250, 258), seq(254, 262))
  expected <- array(expected_data, dim = c(3, 3, 2))

  expect_equivalent(actual, expected)
})

test_that("variable attributes are correct", {
  actual <- ncatt_get(file, "SIS", "units")$value
  expect_equal(actual, "W m-2")

  actual <- ncatt_get(file, "SIS", "_FillValue")$value
  expect_equal(actual, -999)

  actual <- ncatt_get(file, "SIS", "standard_name")$value
  expect_equal(actual, "SIS_standard")

  actual <- ncatt_get(file, "SIS", "long_name")$value
  expect_equal(actual, "Surface Incoming Shortwave Radiation")

  actual <- ncatt_get(file, "SIS", "missing_value")$value
  expect_equal(actual, 0)
})

test_that("attributes are correct", {
  actual <- ncatt_get(file, "lon", "units")$value
  expect_equal(actual, "degrees_east")

  actual <- ncatt_get(file, "lon", "long_name")$value
  expect_equal(actual, "longitude")

  actual <- ncatt_get(file, "lon", "standard_name")$value
  expect_equal(actual, "longitude")

  actual <- ncatt_get(file, "lon", "axis")$value
  expect_equal(actual, "X")

  actual <- ncatt_get(file, "lat", "units")$value
  expect_equal(actual, "degrees_north")

  actual <- ncatt_get(file, "lat", "long_name")$value
  expect_equal(actual, "latitude")

  actual <- ncatt_get(file, "lat", "standard_name")$value
  expect_equal(actual, "latitude")

  actual <- ncatt_get(file, "lat", "axis")$value
  expect_equal(actual, "Y")

  actual <- ncatt_get(file, "time", "units")$value
  expect_equal(actual, "hours since 1983-01-01 00:00:00")

  actual <- ncatt_get(file, "time", "long_name")$value
  expect_equal(actual, "time")

  actual <- ncatt_get(file, "time", "standard_name")$value
  expect_equal(actual, "time")

  actual <- ncatt_get(file, "time", "calendar")$value
  expect_equal(actual, "standard")

  global_attr <- ncatt_get(file, 0)
  expect_equal(length(global_attr), 1)

  actual <- names(global_attr[1])
  expect_equal(actual, "Info")

  actual <- global_attr[[1]]
  expect_equal(actual, "Created with the CM SAF R Toolbox.")
})

test_that("coordinates are correct", {
  actual <- ncvar_get(file, "lon")
  expect_identical(actual, array(seq(5, 6, 0.5)))

  actual <- ncvar_get(file, "lat")
  expect_identical(actual, array(seq(45, 46, 0.5)))

  actual <- ncvar_get(file, "time")
  expect_equal(actual, array(c(149016, 149760)))
})

nc_close(file)

########## output ncdf version 7 #########
file_out <- tempfile_nc()
test_that("error is thrown if ncdf version is wrong", {
  expect_error(
    extract.level("SIS", file.path(data_dir, "ex_extract.level.nc"),
                  file_out, nc34 = 7),
    "nc version must be in c(3, 4), but was 7", fixed = TRUE
  )
})

########## output ncdf version is NULL #########
file_out <- tempfile_nc()
test_that("ncdf version NULL throws an error", {
  expect_error(
    extract.level("SIS",
                  file.path(data_dir, "ex_extract.level.nc"),
                  file_out, nc34 = NULL),
    "nc_version must not be NULL"
  )
})

########## variable does not exist #########
file_out <- tempfile_nc()

test_that("warning is shown if var does not exist", {
  expect_warning(extract.level("notExist",
                               file.path(data_dir, "ex_extract.level.nc"),
                               file_out),
                 "Variable 'notExist' not found. Variable 'SIS' will be used instead.")
})

file <- nc_open(file_out)

test_that("data is correct", {
  actual <- ncvar_get(file)

  expected_data <- c(seq(250, 258), seq(254, 262))
  expected <- array(expected_data, dim = c(3, 3, 2))

  expect_equivalent(actual, expected)
})

test_that("variable attributes are correct", {
  actual <- ncatt_get(file, "SIS", "units")$value
  expect_equal(actual, "W m-2")

  actual <- ncatt_get(file, "SIS", "_FillValue")$value
  expect_equal(actual, -999)

  actual <- ncatt_get(file, "SIS", "standard_name")$value
  expect_equal(actual, "SIS_standard")

  actual <- ncatt_get(file, "SIS", "long_name")$value
  expect_equal(actual, "Surface Incoming Shortwave Radiation")

  actual <- ncatt_get(file, "SIS", "missing_value")$value
  expect_equal(actual, 0)
})

test_that("attributes are correct", {
  actual <- ncatt_get(file, "lon", "units")$value
  expect_equal(actual, "degrees_east")

  actual <- ncatt_get(file, "lon", "long_name")$value
  expect_equal(actual, "longitude")

  actual <- ncatt_get(file, "lon", "standard_name")$value
  expect_equal(actual, "longitude")

  actual <- ncatt_get(file, "lon", "axis")$value
  expect_equal(actual, "X")

  actual <- ncatt_get(file, "lat", "units")$value
  expect_equal(actual, "degrees_north")

  actual <- ncatt_get(file, "lat", "long_name")$value
  expect_equal(actual, "latitude")

  actual <- ncatt_get(file, "lat", "standard_name")$value
  expect_equal(actual, "latitude")

  actual <- ncatt_get(file, "lat", "axis")$value
  expect_equal(actual, "Y")

  actual <- ncatt_get(file, "time", "units")$value
  expect_equal(actual, "hours since 1983-01-01 00:00:00")

  actual <- ncatt_get(file, "time", "long_name")$value
  expect_equal(actual, "time")

  actual <- ncatt_get(file, "time", "standard_name")$value
  expect_equal(actual, "time")

  actual <- ncatt_get(file, "time", "calendar")$value
  expect_equal(actual, "standard")

  global_attr <- ncatt_get(file, 0)
  expect_equal(length(global_attr), 1)

  actual <- names(global_attr[1])
  expect_equal(actual, "Info")

  actual <- global_attr[[1]]
  expect_equal(actual, "Created with the CM SAF R Toolbox.")
})

test_that("coordinates are correct", {
  actual <- ncvar_get(file, "lon")
  expect_identical(actual, array(seq(5, 6, 0.5)))

  actual <- ncvar_get(file, "lat")
  expect_identical(actual, array(seq(45, 46, 0.5)))

  actual <- ncvar_get(file, "time")
  expect_equal(actual, array(c(149016, 149760)))
})

nc_close(file)

########## variable is NULL #########
file_out <- tempfile_nc()
test_that("error is thrown if variable is NULL", {
  expect_error(
    extract.level(NULL,
                  file.path(data_dir, "ex_extract.level.nc"),
                  file_out),
    "variable must not be NULL"
  )
})

########## variable is empty #########
file_out <- tempfile_nc()

test_that("warning is shown if var is empty", {
  expect_warning(extract.level("",
                               file.path(data_dir, "ex_extract.level.nc"),
                               file_out),
                 "Variable '' not found. Variable 'SIS' will be used instead.")
})

file <- nc_open(file_out)

test_that("data is correct", {
  actual <- ncvar_get(file)

  expected_data <- c(seq(250, 258), seq(254, 262))
  expected <- array(expected_data, dim = c(3, 3, 2))

  expect_equivalent(actual, expected)
})

test_that("variable attributes are correct", {
  actual <- ncatt_get(file, "SIS", "units")$value
  expect_equal(actual, "W m-2")

  actual <- ncatt_get(file, "SIS", "_FillValue")$value
  expect_equal(actual, -999)

  actual <- ncatt_get(file, "SIS", "standard_name")$value
  expect_equal(actual, "SIS_standard")

  actual <- ncatt_get(file, "SIS", "long_name")$value
  expect_equal(actual, "Surface Incoming Shortwave Radiation")

  actual <- ncatt_get(file, "SIS", "missing_value")$value
  expect_equal(actual, 0)
})

test_that("attributes are correct", {
  actual <- ncatt_get(file, "lon", "units")$value
  expect_equal(actual, "degrees_east")

  actual <- ncatt_get(file, "lon", "long_name")$value
  expect_equal(actual, "longitude")

  actual <- ncatt_get(file, "lon", "standard_name")$value
  expect_equal(actual, "longitude")

  actual <- ncatt_get(file, "lon", "axis")$value
  expect_equal(actual, "X")

  actual <- ncatt_get(file, "lat", "units")$value
  expect_equal(actual, "degrees_north")

  actual <- ncatt_get(file, "lat", "long_name")$value
  expect_equal(actual, "latitude")

  actual <- ncatt_get(file, "lat", "standard_name")$value
  expect_equal(actual, "latitude")

  actual <- ncatt_get(file, "lat", "axis")$value
  expect_equal(actual, "Y")

  actual <- ncatt_get(file, "time", "units")$value
  expect_equal(actual, "hours since 1983-01-01 00:00:00")

  actual <- ncatt_get(file, "time", "long_name")$value
  expect_equal(actual, "time")

  actual <- ncatt_get(file, "time", "standard_name")$value
  expect_equal(actual, "time")

  actual <- ncatt_get(file, "time", "calendar")$value
  expect_equal(actual, "standard")

  global_attr <- ncatt_get(file, 0)
  expect_equal(length(global_attr), 1)

  actual <- names(global_attr[1])
  expect_equal(actual, "Info")

  actual <- global_attr[[1]]
  expect_equal(actual, "Created with the CM SAF R Toolbox.")
})

test_that("coordinates are correct", {
  actual <- ncvar_get(file, "lon")
  expect_identical(actual, array(seq(5, 6, 0.5)))

  actual <- ncvar_get(file, "lat")
  expect_identical(actual, array(seq(45, 46, 0.5)))

  actual <- ncvar_get(file, "time")
  expect_equal(actual, array(c(149016, 149760)))
})

nc_close(file)

########## input file does not exist #########
file_out <- tempfile_nc()
test_that("error is thrown if input file does not exist", {
  expect_error(
    extract.level("SIS",
                  file.path(data_dir, "xemaple1.nc"),
                  file_out),
    "Input file does not exist")
})

########## input filename is empty #########
file_out <- tempfile_nc()
test_that("error is thrown if input filename is empty", {
  expect_error(
    extract.level("SIS", "", file_out),
    "Input file does not exist")
})

########## input filename is NULL #########
file_out <- tempfile_nc()

test_that("error is thrown if input filename is NULL", {
  expect_error(
    extract.level("SIS", NULL, file_out),
    "Input filepath must be of length one and not NULL"
  )
})

########## output file already exists #########
file_out <- tempfile_nc()
cat("test\n", file = file_out)

test_that("no error is thrown if output file already exists", {
  expect_error(
    extract.level("SIS",
                  file.path(data_dir, "ex_extract.level.nc"),
                  file_out),
    paste0("File '",
           file_out,
           "' already exists. Specify 'overwrite = TRUE' if you want to overwrite it."),
    fixed = TRUE
  )

  expect_equal(readLines(con = file_out), "test")
})

########## output file already exists (overwrite = TRUE) #########
file_out <- tempfile_nc()
cat("test\n", file = file_out)

test_that("no error is thrown if overwrite = TRUE", {
  expect_error(
    extract.level("SIS",
                  file.path(data_dir, "ex_extract.level.nc"),
                  file_out,
                  overwrite = TRUE),
    NA)
})

file <- nc_open(file_out)

test_that("data is correct", {
  actual <- ncvar_get(file)

  expected_data <- c(seq(250, 258), seq(254, 262))
  expected <- array(expected_data, dim = c(3, 3, 2))

  expect_equivalent(actual, expected)
})

test_that("variable attributes are correct", {
  actual <- ncatt_get(file, "SIS", "units")$value
  expect_equal(actual, "W m-2")

  actual <- ncatt_get(file, "SIS", "_FillValue")$value
  expect_equal(actual, -999)

  actual <- ncatt_get(file, "SIS", "standard_name")$value
  expect_equal(actual, "SIS_standard")

  actual <- ncatt_get(file, "SIS", "long_name")$value
  expect_equal(actual, "Surface Incoming Shortwave Radiation")

  actual <- ncatt_get(file, "SIS", "missing_value")$value
  expect_equal(actual, 0)
})

test_that("attributes are correct", {
  actual <- ncatt_get(file, "lon", "units")$value
  expect_equal(actual, "degrees_east")

  actual <- ncatt_get(file, "lon", "long_name")$value
  expect_equal(actual, "longitude")

  actual <- ncatt_get(file, "lon", "standard_name")$value
  expect_equal(actual, "longitude")

  actual <- ncatt_get(file, "lon", "axis")$value
  expect_equal(actual, "X")

  actual <- ncatt_get(file, "lat", "units")$value
  expect_equal(actual, "degrees_north")

  actual <- ncatt_get(file, "lat", "long_name")$value
  expect_equal(actual, "latitude")

  actual <- ncatt_get(file, "lat", "standard_name")$value
  expect_equal(actual, "latitude")

  actual <- ncatt_get(file, "lat", "axis")$value
  expect_equal(actual, "Y")

  actual <- ncatt_get(file, "time", "units")$value
  expect_equal(actual, "hours since 1983-01-01 00:00:00")

  actual <- ncatt_get(file, "time", "long_name")$value
  expect_equal(actual, "time")

  actual <- ncatt_get(file, "time", "standard_name")$value
  expect_equal(actual, "time")

  actual <- ncatt_get(file, "time", "calendar")$value
  expect_equal(actual, "standard")

  global_attr <- ncatt_get(file, 0)
  expect_equal(length(global_attr), 1)

  actual <- names(global_attr[1])
  expect_equal(actual, "Info")

  actual <- global_attr[[1]]
  expect_equal(actual, "Created with the CM SAF R Toolbox.")
})

test_that("coordinates are correct", {
  actual <- ncvar_get(file, "lon")
  expect_identical(actual, array(seq(5, 6, 0.5)))

  actual <- ncvar_get(file, "lat")
  expect_identical(actual, array(seq(45, 46, 0.5)))

  actual <- ncvar_get(file, "time")
  expect_equal(actual, array(c(149016, 149760)))
})

nc_close(file)

########## different level ##########
file_out <- tempfile_nc()
extract.level("SIS", file.path(data_dir, "ex_extract.level.nc"),
              file_out, level = 2)
file <- nc_open(file_out)

test_that("data is correct", {
  actual <- ncvar_get(file)

  expected_data <- c(seq(259, 267), seq(263, 271))
  expected <- array(expected_data, dim = c(3, 3, 2))

  expect_equivalent(actual, expected)
})

test_that("variable attributes are correct", {
  actual <- ncatt_get(file, "SIS", "units")$value
  expect_equal(actual, "W m-2")

  actual <- ncatt_get(file, "SIS", "_FillValue")$value
  expect_equal(actual, -999)

  actual <- ncatt_get(file, "SIS", "standard_name")$value
  expect_equal(actual, "SIS_standard")

  actual <- ncatt_get(file, "SIS", "long_name")$value
  expect_equal(actual, "Surface Incoming Shortwave Radiation")

  actual <- ncatt_get(file, "SIS", "missing_value")$value
  expect_equal(actual, 0)
})

test_that("attributes are correct", {
  actual <- ncatt_get(file, "lon", "units")$value
  expect_equal(actual, "degrees_east")

  actual <- ncatt_get(file, "lon", "long_name")$value
  expect_equal(actual, "longitude")

  actual <- ncatt_get(file, "lon", "standard_name")$value
  expect_equal(actual, "longitude")

  actual <- ncatt_get(file, "lon", "axis")$value
  expect_equal(actual, "X")

  actual <- ncatt_get(file, "lat", "units")$value
  expect_equal(actual, "degrees_north")

  actual <- ncatt_get(file, "lat", "long_name")$value
  expect_equal(actual, "latitude")

  actual <- ncatt_get(file, "lat", "standard_name")$value
  expect_equal(actual, "latitude")

  actual <- ncatt_get(file, "lat", "axis")$value
  expect_equal(actual, "Y")

  actual <- ncatt_get(file, "time", "units")$value
  expect_equal(actual, "hours since 1983-01-01 00:00:00")

  actual <- ncatt_get(file, "time", "long_name")$value
  expect_equal(actual, "time")

  actual <- ncatt_get(file, "time", "standard_name")$value
  expect_equal(actual, "time")

  actual <- ncatt_get(file, "time", "calendar")$value
  expect_equal(actual, "standard")

  global_attr <- ncatt_get(file, 0)
  expect_equal(length(global_attr), 1)

  actual <- names(global_attr[1])
  expect_equal(actual, "Info")

  actual <- global_attr[[1]]
  expect_equal(actual, "Created with the CM SAF R Toolbox.")
})

test_that("coordinates are correct", {
  actual <- ncvar_get(file, "lon")
  expect_identical(actual, array(seq(5, 6, 0.5)))

  actual <- ncvar_get(file, "lat")
  expect_identical(actual, array(seq(45, 46, 0.5)))

  actual <- ncvar_get(file, "time")
  expect_equal(actual, array(c(149016, 149760)))
})

nc_close(file)

########## all levels (dim = (3, 3, 3, 2)) ##########
file_out <- tempfile_nc()
extract.level("SIS", file.path(data_dir, "ex_extract.level.nc"),
              file_out, level = "all")

test_that("three files have been created", {
  expect_true(file.exists(paste0(strsplit(file_out, split = ".nc"), "_level1.nc")))
  expect_true(file.exists(paste0(strsplit(file_out, split = ".nc"), "_level2.nc")))
  expect_true(file.exists(paste0(strsplit(file_out, split = ".nc"), "_level3.nc")))
})

file <- nc_open(paste0(strsplit(file_out, split = ".nc"), "_level1.nc"))

test_that("data is correct", {
  actual <- ncvar_get(file)

  expected_data <- c(seq(250, 258), seq(254, 262))
  expected <- array(expected_data, dim = c(3, 3, 2))

  expect_equivalent(actual, expected)
})

test_that("variable attributes are correct", {
  actual <- ncatt_get(file, "SIS", "units")$value
  expect_equal(actual, "W m-2")

  actual <- ncatt_get(file, "SIS", "_FillValue")$value
  expect_equal(actual, -999)

  actual <- ncatt_get(file, "SIS", "standard_name")$value
  expect_equal(actual, "SIS_standard")

  actual <- ncatt_get(file, "SIS", "long_name")$value
  expect_equal(actual, "Surface Incoming Shortwave Radiation")

  actual <- ncatt_get(file, "SIS", "missing_value")$value
  expect_equal(actual, 0)
})

test_that("attributes are correct", {
  actual <- ncatt_get(file, "lon", "units")$value
  expect_equal(actual, "degrees_east")

  actual <- ncatt_get(file, "lon", "long_name")$value
  expect_equal(actual, "longitude")

  actual <- ncatt_get(file, "lon", "standard_name")$value
  expect_equal(actual, "longitude")

  actual <- ncatt_get(file, "lon", "axis")$value
  expect_equal(actual, "X")

  actual <- ncatt_get(file, "lat", "units")$value
  expect_equal(actual, "degrees_north")

  actual <- ncatt_get(file, "lat", "long_name")$value
  expect_equal(actual, "latitude")

  actual <- ncatt_get(file, "lat", "standard_name")$value
  expect_equal(actual, "latitude")

  actual <- ncatt_get(file, "lat", "axis")$value
  expect_equal(actual, "Y")

  actual <- ncatt_get(file, "time", "units")$value
  expect_equal(actual, "hours since 1983-01-01 00:00:00")

  actual <- ncatt_get(file, "time", "long_name")$value
  expect_equal(actual, "time")

  actual <- ncatt_get(file, "time", "standard_name")$value
  expect_equal(actual, "time")

  actual <- ncatt_get(file, "time", "calendar")$value
  expect_equal(actual, "standard")

  global_attr <- ncatt_get(file, 0)
  expect_equal(length(global_attr), 1)

  actual <- names(global_attr[1])
  expect_equal(actual, "Info")

  actual <- global_attr[[1]]
  expect_equal(actual, "Created with the CM SAF R Toolbox.")
})

test_that("coordinates are correct", {
  actual <- ncvar_get(file, "lon")
  expect_identical(actual, array(seq(5, 6, 0.5)))

  actual <- ncvar_get(file, "lat")
  expect_identical(actual, array(seq(45, 46, 0.5)))

  actual <- ncvar_get(file, "time")
  expect_equal(actual, array(c(149016, 149760)))
})

nc_close(file)

file <- nc_open(paste0(strsplit(file_out, split = ".nc"), "_level2.nc"))

test_that("data is correct", {
  actual <- ncvar_get(file)

  expected_data <- c(seq(259, 267), seq(263, 271))
  expected <- array(expected_data, dim = c(3, 3, 2))

  expect_equivalent(actual, expected)
})

test_that("variable attributes are correct", {
  actual <- ncatt_get(file, "SIS", "units")$value
  expect_equal(actual, "W m-2")

  actual <- ncatt_get(file, "SIS", "_FillValue")$value
  expect_equal(actual, -999)

  actual <- ncatt_get(file, "SIS", "standard_name")$value
  expect_equal(actual, "SIS_standard")

  actual <- ncatt_get(file, "SIS", "long_name")$value
  expect_equal(actual, "Surface Incoming Shortwave Radiation")

  actual <- ncatt_get(file, "SIS", "missing_value")$value
  expect_equal(actual, 0)
})

test_that("attributes are correct", {
  actual <- ncatt_get(file, "lon", "units")$value
  expect_equal(actual, "degrees_east")

  actual <- ncatt_get(file, "lon", "long_name")$value
  expect_equal(actual, "longitude")

  actual <- ncatt_get(file, "lon", "standard_name")$value
  expect_equal(actual, "longitude")

  actual <- ncatt_get(file, "lon", "axis")$value
  expect_equal(actual, "X")

  actual <- ncatt_get(file, "lat", "units")$value
  expect_equal(actual, "degrees_north")

  actual <- ncatt_get(file, "lat", "long_name")$value
  expect_equal(actual, "latitude")

  actual <- ncatt_get(file, "lat", "standard_name")$value
  expect_equal(actual, "latitude")

  actual <- ncatt_get(file, "lat", "axis")$value
  expect_equal(actual, "Y")

  actual <- ncatt_get(file, "time", "units")$value
  expect_equal(actual, "hours since 1983-01-01 00:00:00")

  actual <- ncatt_get(file, "time", "long_name")$value
  expect_equal(actual, "time")

  actual <- ncatt_get(file, "time", "standard_name")$value
  expect_equal(actual, "time")

  actual <- ncatt_get(file, "time", "calendar")$value
  expect_equal(actual, "standard")

  global_attr <- ncatt_get(file, 0)
  expect_equal(length(global_attr), 1)

  actual <- names(global_attr[1])
  expect_equal(actual, "Info")

  actual <- global_attr[[1]]
  expect_equal(actual, "Created with the CM SAF R Toolbox.")
})

test_that("coordinates are correct", {
  actual <- ncvar_get(file, "lon")
  expect_identical(actual, array(seq(5, 6, 0.5)))

  actual <- ncvar_get(file, "lat")
  expect_identical(actual, array(seq(45, 46, 0.5)))

  actual <- ncvar_get(file, "time")
  expect_equal(actual, array(c(149016, 149760)))
})

nc_close(file)

file <- nc_open(paste0(strsplit(file_out, split = ".nc"), "_level3.nc"))

test_that("data is correct", {
  actual <- ncvar_get(file)

  expected_data <- c(seq(268, 272), seq(250, 253), seq(272, 272), seq(250, 257))
  expected <- array(expected_data, dim = c(3, 3, 2))

  expect_equivalent(actual, expected)
})

test_that("variable attributes are correct", {
  actual <- ncatt_get(file, "SIS", "units")$value
  expect_equal(actual, "W m-2")

  actual <- ncatt_get(file, "SIS", "_FillValue")$value
  expect_equal(actual, -999)

  actual <- ncatt_get(file, "SIS", "standard_name")$value
  expect_equal(actual, "SIS_standard")

  actual <- ncatt_get(file, "SIS", "long_name")$value
  expect_equal(actual, "Surface Incoming Shortwave Radiation")

  actual <- ncatt_get(file, "SIS", "missing_value")$value
  expect_equal(actual, 0)
})

test_that("attributes are correct", {
  actual <- ncatt_get(file, "lon", "units")$value
  expect_equal(actual, "degrees_east")

  actual <- ncatt_get(file, "lon", "long_name")$value
  expect_equal(actual, "longitude")

  actual <- ncatt_get(file, "lon", "standard_name")$value
  expect_equal(actual, "longitude")

  actual <- ncatt_get(file, "lon", "axis")$value
  expect_equal(actual, "X")

  actual <- ncatt_get(file, "lat", "units")$value
  expect_equal(actual, "degrees_north")

  actual <- ncatt_get(file, "lat", "long_name")$value
  expect_equal(actual, "latitude")

  actual <- ncatt_get(file, "lat", "standard_name")$value
  expect_equal(actual, "latitude")

  actual <- ncatt_get(file, "lat", "axis")$value
  expect_equal(actual, "Y")

  actual <- ncatt_get(file, "time", "units")$value
  expect_equal(actual, "hours since 1983-01-01 00:00:00")

  actual <- ncatt_get(file, "time", "long_name")$value
  expect_equal(actual, "time")

  actual <- ncatt_get(file, "time", "standard_name")$value
  expect_equal(actual, "time")

  actual <- ncatt_get(file, "time", "calendar")$value
  expect_equal(actual, "standard")

  global_attr <- ncatt_get(file, 0)
  expect_equal(length(global_attr), 1)

  actual <- names(global_attr[1])
  expect_equal(actual, "Info")

  actual <- global_attr[[1]]
  expect_equal(actual, "Created with the CM SAF R Toolbox.")
})

test_that("coordinates are correct", {
  actual <- ncvar_get(file, "lon")
  expect_identical(actual, array(seq(5, 6, 0.5)))

  actual <- ncvar_get(file, "lat")
  expect_identical(actual, array(seq(45, 46, 0.5)))

  actual <- ncvar_get(file, "time")
  expect_equal(actual, array(c(149016, 149760)))
})

nc_close(file)

########## all levels (dim = (5, 5, 3, 2)) ##########
file_out <- tempfile_nc()
extract.level("SIS", file.path(data_dir, "ex_extract.level2.nc"),
              file_out, level = "all")

test_that("three files have been created", {
  expect_true(file.exists(paste0(strsplit(file_out, split = ".nc"), "_level1.nc")))
  expect_true(file.exists(paste0(strsplit(file_out, split = ".nc"), "_level2.nc")))
  expect_true(file.exists(paste0(strsplit(file_out, split = ".nc"), "_level3.nc")))
})

file <- nc_open(paste0(strsplit(file_out, split = ".nc"), "_level1.nc"))

test_that("data is correct", {
  actual <- ncvar_get(file)

  expected_data <- c(seq(250, 272), seq(250, 251), seq(256, 272), seq(250, 257))
  expected <- array(expected_data, dim = c(5, 5, 2))

  expect_equivalent(actual, expected)
})

test_that("variable attributes are correct", {
  actual <- ncatt_get(file, "SIS", "units")$value
  expect_equal(actual, "W m-2")

  actual <- ncatt_get(file, "SIS", "_FillValue")$value
  expect_equal(actual, -999)

  actual <- ncatt_get(file, "SIS", "standard_name")$value
  expect_equal(actual, "SIS_standard")

  actual <- ncatt_get(file, "SIS", "long_name")$value
  expect_equal(actual, "Surface Incoming Shortwave Radiation")

  actual <- ncatt_get(file, "SIS", "missing_value")$value
  expect_equal(actual, 0)
})

test_that("attributes are correct", {
  actual <- ncatt_get(file, "lon", "units")$value
  expect_equal(actual, "degrees_east")

  actual <- ncatt_get(file, "lon", "long_name")$value
  expect_equal(actual, "longitude")

  actual <- ncatt_get(file, "lon", "standard_name")$value
  expect_equal(actual, "longitude")

  actual <- ncatt_get(file, "lon", "axis")$value
  expect_equal(actual, "X")

  actual <- ncatt_get(file, "lat", "units")$value
  expect_equal(actual, "degrees_north")

  actual <- ncatt_get(file, "lat", "long_name")$value
  expect_equal(actual, "latitude")

  actual <- ncatt_get(file, "lat", "standard_name")$value
  expect_equal(actual, "latitude")

  actual <- ncatt_get(file, "lat", "axis")$value
  expect_equal(actual, "Y")

  actual <- ncatt_get(file, "time", "units")$value
  expect_equal(actual, "hours since 1983-01-01 00:00:00")

  actual <- ncatt_get(file, "time", "long_name")$value
  expect_equal(actual, "time")

  actual <- ncatt_get(file, "time", "standard_name")$value
  expect_equal(actual, "time")

  actual <- ncatt_get(file, "time", "calendar")$value
  expect_equal(actual, "standard")

  global_attr <- ncatt_get(file, 0)
  expect_equal(length(global_attr), 1)

  actual <- names(global_attr[1])
  expect_equal(actual, "Info")

  actual <- global_attr[[1]]
  expect_equal(actual, "Created with the CM SAF R Toolbox.")
})

test_that("coordinates are correct", {
  actual <- ncvar_get(file, "lon")
  expect_identical(actual, array(seq(5, 7, 0.5)))

  actual <- ncvar_get(file, "lat")
  expect_identical(actual, array(seq(45, 47, 0.5)))

  actual <- ncvar_get(file, "time")
  expect_equal(actual, array(c(149016, 149760)))
})

nc_close(file)

file <- nc_open(paste0(strsplit(file_out, split = ".nc"), "_level2.nc"))

test_that("data is correct", {
  actual <- ncvar_get(file)

  expected_data <- c(seq(252, 272), seq(250, 253), seq(258, 272), seq(250, 259))
  expected <- array(expected_data, dim = c(5, 5, 2))

  expect_equivalent(actual, expected)
})

test_that("variable attributes are correct", {
  actual <- ncatt_get(file, "SIS", "units")$value
  expect_equal(actual, "W m-2")

  actual <- ncatt_get(file, "SIS", "_FillValue")$value
  expect_equal(actual, -999)

  actual <- ncatt_get(file, "SIS", "standard_name")$value
  expect_equal(actual, "SIS_standard")

  actual <- ncatt_get(file, "SIS", "long_name")$value
  expect_equal(actual, "Surface Incoming Shortwave Radiation")

  actual <- ncatt_get(file, "SIS", "missing_value")$value
  expect_equal(actual, 0)
})

test_that("attributes are correct", {
  actual <- ncatt_get(file, "lon", "units")$value
  expect_equal(actual, "degrees_east")

  actual <- ncatt_get(file, "lon", "long_name")$value
  expect_equal(actual, "longitude")

  actual <- ncatt_get(file, "lon", "standard_name")$value
  expect_equal(actual, "longitude")

  actual <- ncatt_get(file, "lon", "axis")$value
  expect_equal(actual, "X")

  actual <- ncatt_get(file, "lat", "units")$value
  expect_equal(actual, "degrees_north")

  actual <- ncatt_get(file, "lat", "long_name")$value
  expect_equal(actual, "latitude")

  actual <- ncatt_get(file, "lat", "standard_name")$value
  expect_equal(actual, "latitude")

  actual <- ncatt_get(file, "lat", "axis")$value
  expect_equal(actual, "Y")

  actual <- ncatt_get(file, "time", "units")$value
  expect_equal(actual, "hours since 1983-01-01 00:00:00")

  actual <- ncatt_get(file, "time", "long_name")$value
  expect_equal(actual, "time")

  actual <- ncatt_get(file, "time", "standard_name")$value
  expect_equal(actual, "time")

  actual <- ncatt_get(file, "time", "calendar")$value
  expect_equal(actual, "standard")

  global_attr <- ncatt_get(file, 0)
  expect_equal(length(global_attr), 1)

  actual <- names(global_attr[1])
  expect_equal(actual, "Info")

  actual <- global_attr[[1]]
  expect_equal(actual, "Created with the CM SAF R Toolbox.")
})

test_that("coordinates are correct", {
  actual <- ncvar_get(file, "lon")
  expect_identical(actual, array(seq(5, 7, 0.5)))

  actual <- ncvar_get(file, "lat")
  expect_identical(actual, array(seq(45, 47, 0.5)))

  actual <- ncvar_get(file, "time")
  expect_equal(actual, array(c(149016, 149760)))
})

nc_close(file)

file <- nc_open(paste0(strsplit(file_out, split = ".nc"), "_level3.nc"))

test_that("data is correct", {
  actual <- ncvar_get(file)

  expected_data <- c(seq(254, 272), seq(250, 255), seq(260, 272), seq(250, 261))
  expected <- array(expected_data, dim = c(5, 5, 2))

  expect_equivalent(actual, expected)
})

test_that("variable attributes are correct", {
  actual <- ncatt_get(file, "SIS", "units")$value
  expect_equal(actual, "W m-2")

  actual <- ncatt_get(file, "SIS", "_FillValue")$value
  expect_equal(actual, -999)

  actual <- ncatt_get(file, "SIS", "standard_name")$value
  expect_equal(actual, "SIS_standard")

  actual <- ncatt_get(file, "SIS", "long_name")$value
  expect_equal(actual, "Surface Incoming Shortwave Radiation")

  actual <- ncatt_get(file, "SIS", "missing_value")$value
  expect_equal(actual, 0)
})

test_that("attributes are correct", {
  actual <- ncatt_get(file, "lon", "units")$value
  expect_equal(actual, "degrees_east")

  actual <- ncatt_get(file, "lon", "long_name")$value
  expect_equal(actual, "longitude")

  actual <- ncatt_get(file, "lon", "standard_name")$value
  expect_equal(actual, "longitude")

  actual <- ncatt_get(file, "lon", "axis")$value
  expect_equal(actual, "X")

  actual <- ncatt_get(file, "lat", "units")$value
  expect_equal(actual, "degrees_north")

  actual <- ncatt_get(file, "lat", "long_name")$value
  expect_equal(actual, "latitude")

  actual <- ncatt_get(file, "lat", "standard_name")$value
  expect_equal(actual, "latitude")

  actual <- ncatt_get(file, "lat", "axis")$value
  expect_equal(actual, "Y")

  actual <- ncatt_get(file, "time", "units")$value
  expect_equal(actual, "hours since 1983-01-01 00:00:00")

  actual <- ncatt_get(file, "time", "long_name")$value
  expect_equal(actual, "time")

  actual <- ncatt_get(file, "time", "standard_name")$value
  expect_equal(actual, "time")

  actual <- ncatt_get(file, "time", "calendar")$value
  expect_equal(actual, "standard")

  global_attr <- ncatt_get(file, 0)
  expect_equal(length(global_attr), 1)

  actual <- names(global_attr[1])
  expect_equal(actual, "Info")

  actual <- global_attr[[1]]
  expect_equal(actual, "Created with the CM SAF R Toolbox.")
})

test_that("coordinates are correct", {
  actual <- ncvar_get(file, "lon")
  expect_identical(actual, array(seq(5, 7, 0.5)))

  actual <- ncvar_get(file, "lat")
  expect_identical(actual, array(seq(45, 47, 0.5)))

  actual <- ncvar_get(file, "time")
  expect_equal(actual, array(c(149016, 149760)))
})

nc_close(file)