Merge branch 'mrschmidt/optrtdburl' of github.com:firebase/firebase-js-sdk into mrschmidt/optrtdburl

Author: schmidt-sebastian

.changeset/great-dolphins-tie.md

@@ -0,0 +1,5 @@
+---
+"@firebase/database": patch
+---
+
+The SDK can now infer a default database URL if none is provided in the config.

packages/database/test/database.test.ts

@@ -17,7 +17,7 @@
 
 import { expect } from 'chai';
 import firebase from '@firebase/app';
-import { DATABASE_ADDRESS, createTestApp, DATABASE_URL } from './helpers/util';
+import { DATABASE_ADDRESS, createTestApp } from './helpers/util';
 import '../index';
 
 describe('Database Tests', () => {