Add a timeout to clearDatabase

This will trigger in case something goes wrong and a database isn't closed.

test/test-database.js

@@ -107,7 +107,13 @@ function countKanjiWithCharacter(kanji, character) {
 }
 
 
-async function clearDatabase() {
+function clearDatabase(timeout) {
+    return new Promise((resolve, reject) => {
+        const timer = setTimeout(() => {
+            reject(new Error(`clearDatabase failed to resolve after ${timeout}ms`));
+        }, timeout);
+
+        (async () => {
             const indexedDB = global.indexedDB;
             for (const {name} of await indexedDB.databases()) {
                 await new Promise((resolve, reject) => {
@@ -116,6 +122,10 @@ async function clearDatabase() {
                     request.onsuccess = () => resolve();
                 });
             }
+            clearTimeout(timer);
+            resolve();
+        })();
+    });
 }
 
 
@@ -840,11 +850,18 @@ async function testDatabase2() {
 
 
 async function main() {
+    const clearTimeout = 5000;
+    try {
         await testDatabase1();
-    await clearDatabase();
+        await clearDatabase(clearTimeout);
 
         await testDatabase2();
-    await clearDatabase();
+        await clearDatabase(clearTimeout);
+    } catch (e) {
+        console.log(e);
+        process.exit(-1);
+        throw e;
+    }
 }