chore: add proper tests

Author: gagik

package-lock.json

@@ -66,20 +66,25 @@
     "@mongodb-js/mocha-config-devtools": "^1.0.5",
     "@mongodb-js/prettier-config-devtools": "^1.0.2",
     "@mongodb-js/tsconfig-devtools": "^1.0.3",
+    "@types/chai": "^4.2.21",
     "@types/debug": "^4.1.8",
     "@types/decompress": "^4.2.4",
     "@types/mocha": "^9.1.1",
     "@types/node": "^22.15.30",
     "@types/promise-retry": "^1.1.6",
     "@types/proper-lockfile": "^4.1.4",
     "@types/signal-exit": "^3.0.4",
+    "@types/sinon-chai": "^3.2.5",
     "@types/tar": "^6.1.5",
+    "chai": "^4.5.0",
     "depcheck": "^1.4.7",
     "eslint": "^7.25.0",
     "gen-esm-wrapper": "^1.1.3",
     "mocha": "^8.4.0",
     "nyc": "^15.1.0",
     "prettier": "^3.5.3",
+    "sinon": "^9.2.3",
+    "sinon-chai": "^3.7.0",
     "typescript": "^5.0.4"
   }
 }

packages/mongodb-downloader/package.json

@@ -33,8 +33,7 @@ export type MongoDBDownloaderOptions = {
   downloadOptions?: DownloadOptions;
 };
 
-class MongoDBDownloader {
-  // Download mongod + mongos and return the path to a directory containing them.
+export class MongoDBDownloader {
   async downloadMongoDbWithVersionInfo({
     downloadOptions = {},
     version,
@@ -236,6 +235,7 @@ async function withoutLock<T>(
 
 const downloader = new MongoDBDownloader();
 
+/** Download mongod + mongos with version info and return version info and the path to a directory containing them. */
 export async function downloadMongoDbWithVersionInfo({
   downloadOptions = {},
   version,
@@ -249,7 +249,7 @@ export async function downloadMongoDbWithVersionInfo({
     useLockfile,
   });
 }
-
+/** Download mongod + mongos and return the path to a directory containing them. */
 export async function downloadMongoDb(
   ...args: Parameters<typeof downloadMongoDbWithVersionInfo>
 ): Promise<string> {