tests/testthat/test-fetch.R

In RPresto: DBI Connector to Presto

# Copyright (c) Meta Platforms, Inc. and affiliates.
# All rights reserved.
#
# This source code is licensed under the BSD-style license found in the
# LICENSE file in the root directory of this source tree.

context("fetch")

source("utilities.R")

test_that("fetch works with live database", {
  conn <- setup_live_connection()

  result <- dbSendQuery(conn, "SELECT 1 AS n")
  expect_error(
    fetch(result, 1),
    ".*fetching custom number of rows.*is not supported.*"
  )
  expect_equal(fetch(result, -1), tibble::tibble(n = 1))
  expect_true(dbHasCompleted(result))

  result <- dbSendQuery(conn, "SELECT 2 AS n")
  df <- fetch(result)
  expect_true(dbIsValid(result))
})

test_that("fetch works with mock", {
  conn <- setup_mock_connection()
  with_mock(
    `httr::POST` = mock_httr_replies(
      mock_httr_response(
        "http://localhost:8000/v1/statement",
        status_code = 200,
        state = "RUNNING",
        request_body = "SELECT 1 AS n",
        next_uri = "http://localhost:8000/query_1/1"
      )
    ),
    `httr::GET` = mock_httr_replies(
      mock_httr_response(
        "http://localhost:8000/query_1/1",
        status_code = 200,
        data = data.frame(n = 1),
        state = "FINISHED",
        next_uri = "http://localhost:8000/query_1/2"
      ),
      mock_httr_response(
        "http://localhost:8000/query_1/2",
        status_code = 200,
        data = data.frame(n = 2),
        state = "FINISHED"
      )
    ),
    {
      result <- dbSendQuery(conn, "SELECT 1 AS n")
      expect_error(
        fetch(result, 1),
        ".*fetching custom number of rows.*is not supported.*"
      )
      expect_equal(fetch(result), tibble::tibble(n = 1))
      expect_equal(fetch(result, -1), tibble::tibble(n = 2))
      expect_true(dbHasCompleted(result))

      result <- dbSendQuery(conn, "SELECT 1 AS n")
      expect_equal(fetch(result, -1), tibble::tibble(n = c(1, 2)))
    }
  )
})