diff --git a/R/download_cnefe.R b/R/download_cnefe.R
index bef671a..23a19c5 100644
--- a/R/download_cnefe.R
+++ b/R/download_cnefe.R
@@ -34,7 +34,7 @@ download_cnefe <- function(state = "all", progress = TRUE, cache = TRUE) {
   )
 
   if (!cache) {
-    data_dir <- tempfile("standardized_cnefe")
+    data_dir <- fs::path_norm(tempfile("standardized_cnefe"))
   } else {
     data_dir <- get_cache_dir()
   }
@@ -91,11 +91,7 @@ download_files <- function(files_to_download, progress) {
 
   dest_files <- fs::path(download_dir, basename(files_to_download))
 
-  responses <- httr2::req_perform_parallel(
-    requests,
-    paths = dest_files,
-    progress = ifelse(progress == TRUE, "Downloading CNEFE data", FALSE)
-  )
+  responses <- perform_requests_in_parallel(requests, dest_files, progress)
 
   response_errored <- purrr::map_lgl(
     responses,
@@ -104,13 +100,28 @@ download_files <- function(files_to_download, progress) {
 
   # TODO: improve this error
   if (any(response_errored)) {
-    invalid_dest_files <- dest_files[response_errored]
-    fs::file_delete(invalid_dest_files)
-
     stop("Could not download data for one of the states, uh-oh!")
   }
 
   return(dest_files)
 }
 
+perform_requests_in_parallel <- function(requests, dest_files, progress) {
+  # we create this wrapper around httr2::req_perform_parallel just for testing
+  # purposes. it's easier to mock this function when testing than to mock a
+  # function from another package.
+  #
+  # related test: "errors if could not download the data for one or more states"
+  # in test-download_cnefe
+  #
+  # related help page:
+  # https://testthat.r-lib.org/reference/local_mocked_bindings.html
+
+  httr2::req_perform_parallel(
+    requests,
+    paths = dest_files,
+    on_error = "continue",
+    progress = ifelse(progress == TRUE, "Downloading CNEFE data", FALSE)
+  )
+}
 
diff --git a/tests/testthat/test-download_cnefe.R b/tests/testthat/test-download_cnefe.R
new file mode 100644
index 0000000..04077dc
--- /dev/null
+++ b/tests/testthat/test-download_cnefe.R
@@ -0,0 +1,69 @@
+tester <- function(state = "all", progress = TRUE, cache = TRUE) {
+  download_cnefe(state, progress, cache)
+}
+
+test_that("errors with incorrect input", {
+  expect_error(tester(1))
+  expect_error(tester("oie"))
+
+  expect_error(tester(progress = 1))
+  expect_error(tester(progress = NA))
+  expect_error(tester(progress = c(TRUE, TRUE)))
+
+  expect_error(tester(cache = 1))
+  expect_error(tester(cache = NA))
+  expect_error(tester(cache = c(TRUE, TRUE)))
+})
+
+test_that("returns the path to the downloaded files", {
+  result <- tester("AL")
+  expect_identical(
+    result,
+    file.path(get_cache_dir(), "estado=AL/part-0.parquet")
+  )
+
+  states <- c("AC", "AL")
+  result <- tester(states)
+  expect_identical(
+    result,
+    file.path(get_cache_dir(), glue::glue("estado={states}/part-0.parquet"))
+  )
+})
+
+test_that("cache usage is controlled by the cache argument", {
+  result <- tester("AL", cache = TRUE)
+  expect_identical(
+    result,
+    file.path(get_cache_dir(), "estado=AL/part-0.parquet")
+  )
+
+  result <- tester("AL", cache = FALSE)
+  expect_true(
+    grepl(fs::path(fs::path_norm(tempdir()), "standardized_cnefe"), result)
+  )
+})
+
+test_that("errors if could not download the data for one or more states", {
+  local_mocked_bindings(
+    perform_requests_in_parallel = function(...) {
+      httr2::req_perform_parallel(
+        list(httr2::request("FAILURE")),
+        on_error = "continue"
+      )
+    }
+  )
+
+  expect_error(tester("AL", cache = FALSE))
+})
+
+test_that("would download the data of all states if state='all'", {
+  local_mocked_bindings(
+    perform_requests_in_parallel = function(requests, ...) {
+      if (length(requests) == 27) {
+        cli::cli_abort("Too much to download", class = "state_all_succeeded")
+      }
+    }
+  )
+
+  expect_error(tester("all", cache = FALSE), class = "state_all_succeeded")
+})