tests/testthat/test-parquet.R

In duckdb: DBI Package for the DuckDB Database Management System

test_that("parquet reader works on the notorious userdata1 file", {
  con <- dbConnect(duckdb())
  on.exit(dbDisconnect(con))
  res <- dbGetQuery(con, "SELECT * FROM parquet_scan('data/userdata1.parquet')")
  expect_true(TRUE)
})

test_that("parquet reader works with the binary as string flag", {
  con <- dbConnect(duckdb())
  on.exit(dbDisconnect(con))

  res <- dbGetQuery(con, "SELECT typeof(#1) FROM parquet_scan('data/binary_string.parquet',binary_as_string=true) limit 1")
  expect_true(res[1] == "VARCHAR")
})

test_that("duckdb_write_parquet() works as expected", {
  con <- dbConnect(duckdb())
  on.exit(dbDisconnect(con))

  tf <- tempfile()

  # write to parquet
  df_rel <- rel_from_df(con, data.frame(a = 1:3))
  rel_to_parquet(df_rel, tf)

  res_rel <- rel_from_table_function(con, 'read_parquet', list(tf))
  res_df <- rel_to_altrep(res_rel)
  expect_true(identical(res_df, data.frame(a = 1:3)))


  # nulls
  df_na <- data.frame(a = c(1:3, NA, 5:6))

  df_na_rel <- rel_from_df(con, df_na)
  rel_to_parquet(df_na_rel, tf)

  res_rel <- rel_from_table_function(con, 'read_parquet', list(tf))
  res_df <- rel_to_altrep(res_rel)
  expect_true(identical(res_df, df_na))
})

test_that("duckdb rel_to_parquet() throws error with no file name", {
  con <- dbConnect(duckdb())
  on.exit(dbDisconnect(con))

  # write to parquet
  df_rel <- rel_from_df(con, data.frame(a = 1L))
  expect_error(rel_to_parquet(df_rel, ""))
})

test_that("duckdb rel_to_parquet() allows multiple files (#1015)", {
  con <- dbConnect(duckdb())
  on.exit(dbDisconnect(con))

  tf1 <- tempfile(fileext = ".parquet")
  rel1 <- rel_from_df(con, data.frame(a = 1))
  rel_to_parquet(rel1, tf1)

  tf2 <- tempfile(fileext = ".parquet")
  rel2 <- rel_from_df(con, data.frame(a = 2))
  rel_to_parquet(rel2, tf2)

  res_rel <- rel_from_table_function(con, "read_parquet", list(list(c(tf1, tf2))))

  res_df <- rel_to_altrep(res_rel)
  expect_identical(res_df, data.frame(a = c(1, 2)))
})