JS: Add Firebase test with types

javascript/ql/test/library-tests/frameworks/Firebase/FirebaseRef.expected

@@ -1,3 +1,6 @@
+| src/import_assign.ts:4:3:4:17 | db.ref("hello") |
+| src/import_named.ts:4:3:4:17 | db.ref("hello") |
+| src/import_star.ts:4:3:4:17 | db.ref("hello") |
 | tst.js:5:1:5:22 | fb.data ... ef('x') |
 | tst.js:7:3:7:7 | x.ref |
 | tst.js:7:3:7:14 | x.ref.parent |

javascript/ql/test/library-tests/frameworks/Firebase/node_modules/firebase/index.d.ts

@@ -0,0 +1,10 @@
+// Greatly simplified version of the Firebase d.ts file.
+
+declare namespace firebase.database {
+  interface Database {
+    ref(name: string): any;
+  }
+}
+
+export = firebase;
+export as namespace firebase;

javascript/ql/test/library-tests/frameworks/Firebase/src/import_assign.ts

@@ -0,0 +1,5 @@
+import firebase = require("firebase");
+
+function test(db: firebase.database.Database) {
+  db.ref("hello");
+}

javascript/ql/test/library-tests/frameworks/Firebase/src/import_named.ts

@@ -0,0 +1,5 @@
+import { database } from "firebase";
+
+function test(db: database.Database) {
+  db.ref("hello");
+}

javascript/ql/test/library-tests/frameworks/Firebase/src/import_star.ts

@@ -0,0 +1,5 @@
+import * as firebase from "firebase";
+
+function test(db: firebase.database.Database) {
+  db.ref("hello");
+}

javascript/ql/test/library-tests/frameworks/Firebase/tsconfig.json

@@ -0,0 +1,3 @@
+{
+  "include": ["src"]
+}