tests/testthat/test-as-array.R

In nanoarrow: Interface to the 'nanoarrow' 'C' Library

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test_that("as_nanoarrow_array() works for nanoarrow_array", {
  array <- as_nanoarrow_array(1:10)
  expect_identical(as_nanoarrow_array(array), array)

  array <- as_nanoarrow_array(1:10, schema = na_int32())
  expect_identical(as_nanoarrow_array(array), array)

  skip_if_not_installed("arrow")
  casted <- as_nanoarrow_array(array, schema = na_int64())
  expect_identical(infer_nanoarrow_schema(casted)$format, "l")
  expect_identical(convert_array(casted), as.double(1:10))
})

test_that("as_nanoarrow_array() works for logical() -> na_bool()", {
  # Without nulls
  array <- as_nanoarrow_array(c(TRUE, FALSE, TRUE, FALSE), schema = na_bool())
  expect_identical(infer_nanoarrow_schema(array)$format, "b")
  expect_identical(as.raw(array$buffers[[1]]), raw())
  expect_identical(array$offset, 0L)
  expect_identical(array$null_count, 0L)
  expect_identical(
    as.raw(array$buffers[[2]]),
    as.raw(packBits(c(TRUE, FALSE, TRUE, FALSE, rep(FALSE, 4))))
  )

  # With nulls
  array <- as_nanoarrow_array(c(TRUE, FALSE, NA), schema = na_bool())
  expect_identical(infer_nanoarrow_schema(array)$format, "b")
  expect_identical(array$null_count, 1L)
  expect_identical(
    as.raw(array$buffers[[1]]),
    packBits(c(rep(TRUE, 2), FALSE, rep(FALSE, 5)))
  )
  expect_identical(
    as.raw(array$buffers[[2]]),
    as.raw(packBits(c(TRUE, FALSE, FALSE, rep(FALSE, 5))))
  )
})

test_that("as_nanoarrow_array() errors for bad logical() creation", {
  skip_if_not_installed("arrow")
  expect_snapshot_error(
    as_nanoarrow_array(TRUE, schema = na_string())
  )
})

test_that("as_nanoarrow_array() works for logical() -> na_int32()", {
  # Without nulls
  array <- as_nanoarrow_array(c(TRUE, FALSE, TRUE, FALSE), schema = na_int32())
  expect_identical(infer_nanoarrow_schema(array)$format, "i")
  expect_identical(as.raw(array$buffers[[1]]), raw())
  expect_identical(array$offset, 0L)
  expect_identical(array$null_count, 0L)
  expect_identical(
    as.raw(array$buffers[[2]]),
    as.raw(as_nanoarrow_buffer(c(TRUE, FALSE, TRUE, FALSE)))
  )

  # With nulls
  array <- as_nanoarrow_array(c(TRUE, FALSE, NA), schema = na_int32())
  expect_identical(infer_nanoarrow_schema(array)$format, "i")
  expect_identical(array$null_count, 1L)
  expect_identical(
    as.raw(array$buffers[[1]]),
    packBits(c(rep(TRUE, 2), FALSE, rep(FALSE, 5)))
  )
  expect_identical(
    as.raw(array$buffers[[2]]),
    as.raw(as_nanoarrow_buffer(c(TRUE, FALSE, NA)))
  )
})

test_that("as_nanoarrow_array() works for integer() -> na_int32()", {
  # Without nulls
  array <- as_nanoarrow_array(1:10)
  expect_identical(infer_nanoarrow_schema(array)$format, "i")
  expect_identical(as.raw(array$buffers[[1]]), raw())
  expect_identical(array$offset, 0L)
  expect_identical(array$null_count, 0L)
  expect_identical(as.raw(array$buffers[[2]]), as.raw(as_nanoarrow_buffer(1:10)))

  # With nulls
  array <- as_nanoarrow_array(c(1:10, NA))
  expect_identical(infer_nanoarrow_schema(array)$format, "i")
  expect_identical(array$null_count, 1L)
  expect_identical(
    as.raw(array$buffers[[1]]),
    packBits(c(rep(TRUE, 10), FALSE, rep(FALSE, 5)))
  )
  expect_identical(
    as.raw(array$buffers[[2]]),
    as.raw(as_nanoarrow_buffer(c(1:10, NA)))
  )
})

test_that("as_nanoarrow_array() works for integer -> na_int64()", {
  skip_if_not_installed("arrow")
  casted <- as_nanoarrow_array(1:10, schema = na_int64())
  expect_identical(infer_nanoarrow_schema(casted)$format, "l")
  expect_identical(convert_array(casted), as.double(1:10))
})

test_that("as_nanoarrow_array() works for double() -> na_double()", {
  # Without nulls
  array <- as_nanoarrow_array(as.double(1:10))
  expect_identical(infer_nanoarrow_schema(array)$format, "g")
  expect_identical(as.raw(array$buffers[[1]]), raw())
  expect_identical(array$offset, 0L)
  expect_identical(array$null_count, 0L)
  expect_identical(
    as.raw(array$buffers[[2]]),
    as.raw(as_nanoarrow_buffer(as.double(1:10)))
  )

  # With nulls
  array <- as_nanoarrow_array(c(1:10, NA_real_))
  expect_identical(infer_nanoarrow_schema(array)$format, "g")
  expect_identical(array$null_count, 1L)
  expect_identical(
    as.raw(array$buffers[[1]]),
    packBits(c(rep(TRUE, 10), FALSE, rep(FALSE, 5)))
  )
  expect_identical(
    as.raw(array$buffers[[2]]),
    as.raw(as_nanoarrow_buffer(c(1:10, NA_real_)))
  )
})

test_that("as_nanoarrow_array() works for double() -> na_int32()", {
  # Without nulls
  array <- as_nanoarrow_array(as.double(1:10), schema = na_int32())
  expect_identical(infer_nanoarrow_schema(array)$format, "i")
  expect_identical(as.raw(array$buffers[[1]]), raw())
  expect_identical(array$offset, 0L)
  expect_identical(array$null_count, 0L)
  expect_identical(
    as.raw(array$buffers[[2]]),
    as.raw(as_nanoarrow_buffer(1:10))
  )

  # With nulls
  array <- as_nanoarrow_array(c(1:10, NA_real_), schema = na_int32())
  expect_identical(infer_nanoarrow_schema(array)$format, "i")
  expect_identical(array$null_count, 1L)
  expect_identical(
    as.raw(array$buffers[[1]]),
    packBits(c(rep(TRUE, 10), FALSE, rep(FALSE, 5)))
  )
  # The last element here is 0 because (int)nan is undefined behaviour
  expect_identical(
    as.raw(array$buffers[[2]]),
    as.raw(as_nanoarrow_buffer(c(1:10, 0L)))
  )

  # With overflow
  expect_warning(
    as_nanoarrow_array(.Machine$integer.max + as.double(1:5), schema = na_int32()),
    class = "nanoarrow_warning_lossy_conversion"
  )
})

test_that("as_nanoarrow_array() works for double() -> na_int64()", {
  # Without nulls
  array <- as_nanoarrow_array(as.double(1:10), schema = na_int64())
  expect_identical(infer_nanoarrow_schema(array)$format, "l")
  expect_identical(as.raw(array$buffers[[1]]), raw())
  expect_identical(array$offset, 0L)
  expect_identical(array$null_count, 0L)
  # This *is* how we create int64 buffers, so just check the roundtrip
  expect_identical(convert_array(array), as.double(1:10))

  # With nulls
  array <- as_nanoarrow_array(c(1:10, NA_real_), schema = na_int64())
  expect_identical(infer_nanoarrow_schema(array)$format, "l")
  expect_identical(array$null_count, 1L)
  expect_identical(
    as.raw(array$buffers[[1]]),
    packBits(c(rep(TRUE, 10), FALSE, rep(FALSE, 5)))
  )
  expect_identical(convert_array(array), as.double(c(1:10, NA_real_)))
})

test_that("as_nanoarrow_array() works for integer64() -> na_int32()", {
  skip_if_not_installed("bit64")

  # Without nulls
  array <- as_nanoarrow_array(bit64::as.integer64(1:10), schema = na_int32())
  expect_identical(infer_nanoarrow_schema(array)$format, "i")
  expect_identical(as.raw(array$buffers[[1]]), raw())
  expect_identical(array$offset, 0L)
  expect_identical(array$null_count, 0L)
  expect_identical(
    as.raw(array$buffers[[2]]),
    as.raw(as_nanoarrow_buffer(1:10))
  )

  # With nulls
  array <- as_nanoarrow_array(bit64::as.integer64(c(1:10, NA_real_)), schema = na_int32())
  expect_identical(infer_nanoarrow_schema(array)$format, "i")
  expect_identical(array$null_count, 1L)
  expect_identical(
    as.raw(array$buffers[[1]]),
    packBits(c(rep(TRUE, 10), FALSE, rep(FALSE, 5)))
  )
  # The last element here is 0 because (int)nan is undefined behaviour
  expect_identical(
    as.raw(array$buffers[[2]]),
    as.raw(as_nanoarrow_buffer(c(1:10, 0L)))
  )
})

test_that("as_nanoarrow_array() works for integer64() -> na_int64()", {
  skip_if_not_installed("bit64")

  # Default roundtrip
  array <- as_nanoarrow_array(bit64::as.integer64(1:10))
  expect_identical(convert_array(array, double()), as.double(1:10))

  # Without nulls
  array <- as_nanoarrow_array(bit64::as.integer64(1:10), schema = na_int64())
  expect_identical(infer_nanoarrow_schema(array)$format, "l")
  expect_identical(as.raw(array$buffers[[1]]), raw())
  expect_identical(array$offset, 0L)
  expect_identical(array$null_count, 0L)
  # This *is* how we create int64 buffers, so just check the roundtrip
  expect_identical(convert_array(array, double()), as.double(1:10))

  # With nulls
  array <- as_nanoarrow_array(bit64::as.integer64(c(1:10, NA_real_)), schema = na_int64())
  expect_identical(infer_nanoarrow_schema(array)$format, "l")
  expect_identical(array$null_count, 1L)
  expect_identical(
    as.raw(array$buffers[[1]]),
    packBits(c(rep(TRUE, 10), FALSE, rep(FALSE, 5)))
  )
  expect_identical(convert_array(array, double()), as.double(c(1:10, NA_real_)))
})

test_that("as_nanoarrow_array() works for double -> na_int8()", {
  skip_if_not_installed("arrow")
  casted <- as_nanoarrow_array(as.double(1:10), schema = na_int8())
  expect_identical(infer_nanoarrow_schema(casted)$format, "c")
  expect_identical(convert_array(casted), 1:10)
})

test_that("as_nanoarrow_array() works for character() -> na_string()", {
  # Without nulls
  array <- as_nanoarrow_array(letters)
  expect_identical(infer_nanoarrow_schema(array)$format, "u")
  expect_identical(as.raw(array$buffers[[1]]), raw())
  expect_identical(array$offset, 0L)
  expect_identical(array$null_count, 0L)
  expect_identical(
    as.raw(array$buffers[[2]]),
    as.raw(as_nanoarrow_buffer(0:26))
  )
  expect_identical(
    as.raw(array$buffers[[3]]),
    as.raw(as_nanoarrow_buffer(paste(letters, collapse = "")))
  )

  # With nulls
  array <- as_nanoarrow_array(c(letters, NA))
  expect_identical(infer_nanoarrow_schema(array)$format, "u")
  expect_identical(array$null_count, 1L)
  expect_identical(
    as.raw(array$buffers[[1]]),
    packBits(c(rep(TRUE, 26), FALSE, rep(FALSE, 5)))
  )
  expect_identical(
    as.raw(array$buffers[[2]]),
    as.raw(as_nanoarrow_buffer(c(0:26, 26L)))
  )
  expect_identical(
    as.raw(array$buffers[[3]]),
    as.raw(as_nanoarrow_buffer(paste(letters, collapse = "")))
  )
})

test_that("as_nanoarrow_array() works for character() -> na_large_string()", {
  skip_if_not_installed("arrow")

  # Without nulls
  array <- as_nanoarrow_array(letters, schema = na_large_string())
  expect_identical(infer_nanoarrow_schema(array)$format, "U")
  expect_identical(as.raw(array$buffers[[1]]), raw())
  expect_identical(array$offset, 0L)
  expect_identical(array$null_count, 0L)
  expect_identical(
    as.raw(array$buffers[[3]]),
    as.raw(as_nanoarrow_buffer(paste(letters, collapse = "")))
  )

  # With nulls
  array <- as_nanoarrow_array(c(letters, NA), schema = na_large_string())
  expect_identical(infer_nanoarrow_schema(array)$format, "U")
  expect_identical(array$null_count, 1L)
  expect_identical(
    as.raw(array$buffers[[1]]),
    packBits(c(rep(TRUE, 26), FALSE, rep(FALSE, 5)))
  )
  expect_identical(
    as.raw(array$buffers[[3]]),
    as.raw(as_nanoarrow_buffer(paste(letters, collapse = "")))
  )
})

test_that("as_nanoarrow_array() works for factor() -> na_dictionary()", {
  array <- as_nanoarrow_array(
    factor(letters),
    schema = na_dictionary(na_string(), na_int32())
  )

  expect_identical(infer_nanoarrow_schema(array)$format, "i")
  expect_identical(infer_nanoarrow_schema(array$dictionary)$format, "u")

  expect_identical(as.raw(array$buffers[[1]]), raw())
  expect_identical(
    as.raw(array$buffers[[2]]),
    as.raw(as_nanoarrow_buffer(0:25))
  )

  expect_identical(
    as.raw(array$dictionary$buffers[[3]]),
    charToRaw(paste0(letters, collapse = ""))
  )
})

test_that("as_nanoarrow_array() works for factor() -> na_string()", {
  array <- as_nanoarrow_array(
    factor(letters),
    schema = na_string()
  )

  expect_identical(infer_nanoarrow_schema(array)$format, "u")
  expect_null(array$dictionary)

  expect_identical(as.raw(array$buffers[[1]]), raw())
  expect_identical(
    as.raw(array$buffers[[2]]),
    as.raw(as_nanoarrow_buffer(0:26))
  )
  expect_identical(
    as.raw(array$buffers[[3]]),
    charToRaw(paste0(letters, collapse = ""))
  )
})

test_that("as_nanoarrow_array() works for data.frame() -> na_struct()", {
  array <- as_nanoarrow_array(data.frame(x = 1:10))
  expect_identical(array$length, 10L)
  expect_identical(array$offset, 0L)
  expect_identical(array$null_count, 0L)
  expect_identical(infer_nanoarrow_schema(array)$format, "+s")
  expect_identical(infer_nanoarrow_schema(array$children$x)$format, "i")
  expect_identical(as.raw(array$children$x$buffers[[2]]), as.raw(as_nanoarrow_buffer(1:10)))
})

test_that("as_nanoarrow_array() errors for bad data.frame() -> na_struct()", {
  expect_error(
    as_nanoarrow_array(data.frame(x = 1:10), schema = na_struct()),
    "Expected 1 schema children"
  )

  skip_if_not_installed("arrow")
  expect_snapshot_error(
    as_nanoarrow_array(data.frame(x = 1:10), schema = na_int32())
  )
})

test_that("as_nanoarrow_array() works for Date -> na_date32()", {
  array <- as_nanoarrow_array(as.Date(c("2000-01-01", "2023-02-03", NA)))

  expect_identical(infer_nanoarrow_schema(array)$format, "tdD")
  expect_identical(array$length, 3L)
  expect_identical(array$null_count, 1L)

  expect_identical(as.raw(array$buffers[[1]]), as.raw(0x03))
  expect_identical(
    as.raw(array$buffers[[2]]),
    as.raw(as_nanoarrow_buffer(c(10957L, 19391L, NA)))
  )
})

test_that("as_nanoarrow_array() works for Date -> na_date64()", {
  array <- as_nanoarrow_array(
    as.Date(c("2000-01-01", "2023-02-03", NA)),
    schema = na_date64()
  )

  expect_identical(infer_nanoarrow_schema(array)$format, "tdm")
  expect_identical(array$length, 3L)
  expect_identical(array$null_count, 1L)

  expect_identical(as.raw(array$buffers[[1]]), as.raw(0x03))
  storage <- as_nanoarrow_array(
    c(10957L, 19391L, NA) * 86400000,
    schema = na_int64()
  )

  expect_identical(
    as.raw(array$buffers[[2]]),
    as.raw(storage$buffers[[2]])
  )
})

test_that("as_nanoarrow_array() works for POSIXct -> na_timestamp()", {
  array <- as_nanoarrow_array(
    as.POSIXct(c("2000-01-01", "2023-02-03", NA), tz = "UTC"),
    schema = na_timestamp("ms", timezone = "UTC")
  )

  expect_identical(infer_nanoarrow_schema(array)$format, "tsm:UTC")
  expect_identical(array$length, 3L)
  expect_identical(array$null_count, 1L)

  expect_identical(as.raw(array$buffers[[1]]), as.raw(0x03))
  storage <- as_nanoarrow_array(
    c(10957L, 19391L, NA) * 86400000,
    schema = na_int64()
  )

  expect_identical(
    as.raw(array$buffers[[2]]),
    as.raw(storage$buffers[[2]])
  )
})

test_that("as_nanoarrow_array() works for difftime -> na_duration()", {
  array <- as_nanoarrow_array(
    as.difftime(c(1:5, NA), units = "secs"),
    schema = na_duration("ms")
  )

  expect_identical(infer_nanoarrow_schema(array)$format, "tDm")
  expect_identical(array$length, 6L)
  expect_identical(array$null_count, 1L)

  expect_identical(
    as.raw(array$buffers[[1]]),
    packBits(c(rep(TRUE, 5), FALSE, rep(FALSE, 2)))
  )
  storage <- as_nanoarrow_array(
    c(1:5, NA) * 1000,
    schema = na_int64()
  )

  expect_identical(
    as.raw(array$buffers[[2]]),
    as.raw(storage$buffers[[2]])
  )
})

test_that("as_nanoarrow_array() works for blob::blob() -> na_binary()", {
  skip_if_not_installed("blob")

  # Without nulls
  array <- as_nanoarrow_array(blob::as_blob(letters))
  expect_identical(infer_nanoarrow_schema(array)$format, "z")
  expect_identical(as.raw(array$buffers[[1]]), raw())
  expect_identical(array$offset, 0L)
  expect_identical(array$null_count, 0L)
  expect_identical(
    as.raw(array$buffers[[2]]),
    as.raw(as_nanoarrow_buffer(0:26))
  )
  expect_identical(
    as.raw(array$buffers[[3]]),
    as.raw(as_nanoarrow_buffer(paste(letters, collapse = "")))
  )

  # With nulls
  array <- as_nanoarrow_array(blob::as_blob(c(letters, NA)))
  expect_identical(infer_nanoarrow_schema(array)$format, "z")
  expect_identical(array$null_count, 1L)
  expect_identical(
    as.raw(array$buffers[[1]]),
    packBits(c(rep(TRUE, 26), FALSE, rep(FALSE, 5)))
  )
  expect_identical(
    as.raw(array$buffers[[2]]),
    as.raw(as_nanoarrow_buffer(c(0:26, 26L)))
  )
  expect_identical(
    as.raw(array$buffers[[3]]),
    as.raw(as_nanoarrow_buffer(paste(letters, collapse = "")))
  )
})

test_that("as_nanoarrow_array() works for blob::blob() -> na_large_binary()", {
  skip_if_not_installed("arrow")

  # Without nulls
  array <- as_nanoarrow_array(blob::as_blob(letters), schema = na_large_binary())
  expect_identical(infer_nanoarrow_schema(array)$format, "Z")
  expect_identical(as.raw(array$buffers[[1]]), raw())
  expect_identical(array$offset, 0L)
  expect_identical(array$null_count, 0L)
  expect_identical(
    as.raw(array$buffers[[3]]),
    as.raw(as_nanoarrow_buffer(paste(letters, collapse = "")))
  )

  # With nulls
  array <- as_nanoarrow_array(
    blob::as_blob(c(letters, NA)),
    schema = na_large_binary()
  )
  expect_identical(infer_nanoarrow_schema(array)$format, "Z")
  expect_identical(array$null_count, 1L)
  expect_identical(
    as.raw(array$buffers[[1]]),
    packBits(c(rep(TRUE, 26), FALSE, rep(FALSE, 5)))
  )
  expect_identical(
    as.raw(array$buffers[[3]]),
    as.raw(as_nanoarrow_buffer(paste(letters, collapse = "")))
  )
})


test_that("as_nanoarrow_array() works for list(raw()) -> na_binary()", {
  # Without nulls
  array <- as_nanoarrow_array(lapply(letters, charToRaw))
  expect_identical(infer_nanoarrow_schema(array)$format, "z")
  expect_identical(as.raw(array$buffers[[1]]), raw())
  expect_identical(array$offset, 0L)
  expect_identical(array$null_count, 0L)
  expect_identical(
    as.raw(array$buffers[[2]]),
    as.raw(as_nanoarrow_buffer(0:26))
  )
  expect_identical(
    as.raw(array$buffers[[3]]),
    as.raw(as_nanoarrow_buffer(paste(letters, collapse = "")))
  )

  # With nulls
  array <- as_nanoarrow_array(c(lapply(letters, charToRaw), list(NULL)))
  expect_identical(infer_nanoarrow_schema(array)$format, "z")
  expect_identical(array$null_count, 1L)
  expect_identical(
    as.raw(array$buffers[[1]]),
    packBits(c(rep(TRUE, 26), FALSE, rep(FALSE, 5)))
  )
  expect_identical(
    as.raw(array$buffers[[2]]),
    as.raw(as_nanoarrow_buffer(c(0:26, 26L)))
  )
  expect_identical(
    as.raw(array$buffers[[3]]),
    as.raw(as_nanoarrow_buffer(paste(letters, collapse = "")))
  )
})

test_that("as_nanoarrow_array() works for list(NULL) -> na_list(na_na())", {
  array <- as_nanoarrow_array(list(NULL))
  expect_identical(infer_nanoarrow_schema(array)$format, "+l")
  expect_identical(array$length, 1L)
  expect_identical(array$null_count, 1L)
  expect_identical(
    as.raw(array$buffers[[1]]),
    as.raw(as_nanoarrow_array(FALSE)$buffers[[2]])
  )
  expect_identical(
    as.raw(array$buffers[[2]]),
    as.raw(as_nanoarrow_buffer(c(0L, 0L)))
  )
  expect_identical(infer_nanoarrow_schema(array$children[[1]])$format, "n")
  expect_identical(array$children[[1]]$length, 0L)
})

test_that("as_nanoarrow_array() works for list(integer()) -> na_list(na_int32())", {
  array <- as_nanoarrow_array(list(1:5, 6:10), schema = na_list(na_int32()))
  expect_identical(infer_nanoarrow_schema(array)$format, "+l")
  expect_identical(array$length, 2L)
  expect_identical(array$null_count, 0L)
  expect_identical(
    as.raw(array$buffers[[1]]),
    as.raw(as_nanoarrow_array(c(TRUE, TRUE))$buffers[[2]])
  )
  expect_identical(
    as.raw(array$buffers[[2]]),
    as.raw(as_nanoarrow_buffer(c(0L, 5L, 10L)))
  )
  expect_identical(infer_nanoarrow_schema(array$children[[1]])$format, "i")
  expect_identical(array$children[[1]]$length, 10L)
})

test_that("as_nanoarrow_array() works for unspecified() -> na_na()", {
  skip_if_not_installed("vctrs")

  array <- as_nanoarrow_array(vctrs::unspecified(5))
  expect_identical(infer_nanoarrow_schema(array)$format, "n")
  expect_identical(array$length, 5L)
  expect_identical(array$null_count, 5L)
})

test_that("as_nanoarrow_array() works for bad unspecified() create", {
  skip_if_not_installed("vctrs")
  skip_if_not_installed("arrow")
  expect_snapshot_error(
    as_nanoarrow_array(vctrs::unspecified(5), schema = na_interval_day_time())
  )
})

test_that("as_nanoarrow_array() can convert data.frame() to sparse_union()", {
  # Features: At least one element with more than one non-NA value,
  # one element with all NA values.
  test_df <- data.frame(
    lgl = c(TRUE, NA, NA, NA, NA, FALSE),
    int = c(NA, 123L, NA, NA, NA, NA),
    dbl = c(NA, NA, 456, NA, NA, NA),
    chr = c(NA, NA, NA, "789", NA, NA),
    stringsAsFactors = FALSE
  )

  array <- as_nanoarrow_array(
    test_df,
    schema = na_sparse_union(lapply(test_df, infer_nanoarrow_schema))
  )

  expect_identical(infer_nanoarrow_schema(array)$format, "+us:0,1,2,3")
  expect_identical(array$length, 6L)
  expect_identical(array$null_count, 0L)
  expect_identical(
    as.raw(array$buffers[[1]]),
    as.raw(as_nanoarrow_buffer(as.raw(c(0L, 1L, 2L, 3L, 0L, 0L))))
  )

  expect_identical(
    lapply(array$children, convert_array),
    lapply(test_df, identity)
  )
  expect_identical(convert_array(array), test_df)
})

test_that("as_nanoarrow_array() can convert data.frame() to sparse_union()", {
  test_df <- data.frame(
    lgl = c(TRUE, NA, NA, NA, NA, FALSE),
    int = c(NA, 123L, NA, NA, NA, NA),
    dbl = c(NA, NA, 456, NA, NA, NA),
    chr = c(NA, NA, NA, "789", NA, NA),
    stringsAsFactors = FALSE
  )

  array <- as_nanoarrow_array(
    test_df,
    schema = na_dense_union(lapply(test_df, infer_nanoarrow_schema))
  )

  expect_identical(infer_nanoarrow_schema(array)$format, "+ud:0,1,2,3")
  expect_identical(array$length, 6L)
  expect_identical(array$null_count, 0L)
  expect_identical(
    as.raw(array$buffers[[1]]),
    as.raw(as_nanoarrow_buffer(as.raw(c(0L, 1L, 2L, 3L, 0L, 0L))))
  )
  expect_identical(
    as.raw(array$buffers[[2]]),
    as.raw(as_nanoarrow_buffer(c(0L, 0L, 0L, 0L, 1L, 2L)))
  )

  expect_identical(
    lapply(array$children, convert_array),
    list(
      lgl = c(TRUE, NA, FALSE),
      int = 123L,
      dbl = 456,
      chr = "789"
    )
  )
  expect_identical(convert_array(array), test_df)
})

test_that("as_nanoarrow_array() for union type errors for unsupported objects", {
  expect_error(
    as_nanoarrow_array(data.frame(), schema = na_dense_union()),
    "Can't convert data frame with 0 columns"
  )
})