vitest.setup.js

import fs from "node:fs";
import { beforeAll } from "vitest";

const testDataDir = "test-data";
beforeAll(async () => {
  if (!fs.existsSync(testDataDir)) {
    fs.mkdirSync(testDataDir);

    //~ Tan et al. 2018
    const url =
      "https://dl.dropboxusercontent.com/scl/fi/lzv3ba5paum6srhte4z2t/GSM3271406_pbmc_18.impute.3dg.txt?rlkey=dc7k1gg5ghv2v7dsl0gg1uoo9&dl=0";
    const filename = "tan2018.tsv";
    await downloadFile(url, filename);
  } else {
    console.log("no need to fetch test data");
  }
});

async function downloadFile(url, filename) {
  console.log(`downloading: ${url}`);
  const file = await fetchFile(url);
  const path = `${testDataDir}/${filename}`;
  fs.writeFileSync(path, file);
}

async function fetchFile(url) {
  const response = await fetch(url);
  if (!response.ok) throw new Error(`fetch failed: ${response.status}`);
  const fileContent = await response.text();
  return fileContent;
}