Throw a more helpful error if there isn't a 'sub' field (#1366)

* Throw a more helpful error if there isn't a 'sub' field

* fix test

Author: ryanpbrewster

packages/testing/src/api/index.ts

@@ -63,6 +63,9 @@ function createUnsecuredJwt(auth: object): string {
   (auth as any).iat = (auth as any).iat || 0;
   // Use `uid` field as a backup when `sub` is missing.
   (auth as any).sub = (auth as any).sub || (auth as any).uid;
+  if (!(auth as any).sub) {
+    throw new Error("auth must be an object with a 'sub' or 'uid' field");
+  }
   // Unsecured JWTs use the empty string as a signature.
   const signature = '';
   return [

packages/testing/test/database.test.ts

@@ -117,9 +117,9 @@ describe('Testing Module Tests', function() {
 
   it('apps() returns apps created with initializeTestApp', async function() {
     const numApps = firebase.apps().length;
-    await firebase.initializeTestApp({ databaseName: 'foo', auth: {} });
+    await firebase.initializeTestApp({ databaseName: 'foo', auth: null });
     expect(firebase.apps().length).to.equal(numApps + 1);
-    await firebase.initializeTestApp({ databaseName: 'bar', auth: {} });
+    await firebase.initializeTestApp({ databaseName: 'bar', auth: null });
     expect(firebase.apps().length).to.equal(numApps + 2);
   });