#' spec_arrow_fetch_arrow

#' @family Arrow specifications

#' @usage NULL

#' @format NULL

#' @keywords NULL

spec_arrow_fetch_arrow <- list(

arrow_fetch_arrow_formals = function() {

# <establish formals of described functions>

expect_equal(names(formals(dbFetchArrow)), c("res", "..."))

},

arrow_fetch_arrow_atomic = function(con) {

#' @return

#' `dbFetchArrow()` always returns an object coercible to a [data.frame] with

#' as many rows as records were fetched and as many

#' columns as fields in the result set,

#' even if the result is a single value

query <- trivial_query()

res <- local_result(dbSendQueryArrow(con, query))

rows <- check_arrow(dbFetchArrow(res))

expect_equal(rows, data.frame(a = 1.5))

},

arrow_fetch_arrow_one_row = function(con) {

#' or has one

query <- trivial_query(3, letters[1:3])

result <- trivial_df(3, letters[1:3])

res <- local_result(dbSendQueryArrow(con, query))

rows <- check_arrow(dbFetchArrow(res))

expect_identical(rows, result)

},

arrow_fetch_arrow_zero_rows = function(con) {

#' or zero rows.

query <-

"SELECT * FROM (SELECT 1 as a, 2 as b, 3 as c) AS x WHERE (1 = 0)"

res <- local_result(dbSendQueryArrow(con, query))

rows <- check_arrow(dbFetchArrow(res))

expect_identical(class(rows), "data.frame")

},

#'

arrow_fetch_arrow_closed = function(ctx, con) {

skip_if_not_dbitest(ctx, "1.8.0.15")

#' @section Failure modes:

#' An attempt to fetch from a closed result set raises an error.

query <- trivial_query()

res <- dbSendQueryArrow(con, query)

dbClearResult(res)

expect_error(dbFetchArrow(res))

},

arrow_fetch_arrow_multi_row_single_column = function(ctx, con) {

#' @section Specification:

#' Fetching multi-row queries with one

query <- trivial_query(3, .ctx = ctx, .order_by = "a")

result <- trivial_df(3)

res <- local_result(dbSendQueryArrow(con, query))

rows <- check_arrow(dbFetchArrow(res))

expect_identical(rows, result)

},

arrow_fetch_arrow_multi_row_multi_column = function(ctx, con) {

#' or more columns by default returns the entire result.

query <- sql_union(

.ctx = ctx, paste("SELECT", 1:5 + 0.5, "AS a,", 4:0 + 0.5, "AS b"), .order_by = "a"

)

res <- local_result(dbSendQueryArrow(con, query))

rows <- check_arrow(dbFetchArrow(res))

expect_identical(rows, data.frame(a = 1:5 + 0.5, b = 4:0 + 0.5))

},

arrow_fetch_arrow_record_batch_reader = function(ctx, con) {

#' The object returned by `dbFetchArrow()` can also be passed to

#' [nanoarrow::as_nanoarrow_array_stream()] to create a nanoarrow

#' array stream object that can be used to read the result set

#' in batches.

query <- trivial_query(25, .ctx = ctx, .order_by = "a")

result <- trivial_df(25)

res <- local_result(dbSendQueryArrow(con, query))

stream <- dbFetchArrow(res)

rbr <- nanoarrow::as_nanoarrow_array_stream(stream)

#' The chunk size is implementation-specific.

out <- as.data.frame(rbr$get_next())

expect_equal(out, head(result, nrow(out)))

},

#

NULL

)