From e38641cd732d77d1873bce470513af2cf80e13ec Mon Sep 17 00:00:00 2001
From: Alex Dvornikov <advornikov@fb.com>
Date: Thu, 8 Jun 2017 12:40:19 -0700
Subject: [PATCH] Fixed error in _getCallableModule method in MessageQueue

Reviewed By: javache

Differential Revision: D5208462

fbshipit-source-id: 13f71e2b7988305eccfa91c349ff120fad9129f0
---
 Libraries/BatchedBridge/MessageQueue.js       |  3 +-
 .../__tests__/MessageQueue-test.js            | 29 +++++++++++++++++++
 2 files changed, 31 insertions(+), 1 deletion(-)

diff --git a/Libraries/BatchedBridge/MessageQueue.js b/Libraries/BatchedBridge/MessageQueue.js
index 173b17709..579dc3065 100644
--- a/Libraries/BatchedBridge/MessageQueue.js
+++ b/Libraries/BatchedBridge/MessageQueue.js
@@ -152,7 +152,8 @@ class MessageQueue {
   }
 
   _getCallableModule(name: string) {
-    return this._lazyCallableModules[name]();
+    const getValue = this._lazyCallableModules[name];
+    return getValue ? getValue() : null;
   }
 
   enqueueNativeCall(moduleID: number, methodID: number, params: Array<any>, onFail: ?Function, onSucc: ?Function) {
diff --git a/Libraries/BatchedBridge/__tests__/MessageQueue-test.js b/Libraries/BatchedBridge/__tests__/MessageQueue-test.js
index 1da3557ca..7b6244ee7 100644
--- a/Libraries/BatchedBridge/__tests__/MessageQueue-test.js
+++ b/Libraries/BatchedBridge/__tests__/MessageQueue-test.js
@@ -83,4 +83,33 @@ describe('MessageQueue', function() {
     queue.__invokeCallback(1);
     expect(() => queue.__invokeCallback(0)).toThrow();
   });
+
+  it('should throw when calling with unknown module', () => {
+    const unknownModule = 'UnknownModule', unknownMethod = 'UnknownMethod';
+    expect(() => queue.__callFunction(unknownModule, unknownMethod)).toThrow(
+      `Module ${unknownModule} is not a registered callable module (calling ${unknownMethod})`,
+    );
+  });
+
+  it('should return lazily registered module', () => {
+    const dummyModule = {}, name = 'modulesName';
+    queue.registerLazyCallableModule(name, () => dummyModule);
+    expect(queue._getCallableModule(name)).toEqual(dummyModule);
+  });
+
+  it('should not initialize lazily registered module before it was used for the first time', () => {
+    const dummyModule = {}, name = 'modulesName';
+    const factory = jest.fn(() => dummyModule);
+    queue.registerLazyCallableModule(name, factory);
+    expect(factory).not.toHaveBeenCalled();
+  });
+
+  it('should initialize lazily registered module only once', () => {
+    const dummyModule = {}, name = 'modulesName';
+    const factory = jest.fn(() => dummyModule);
+    queue.registerLazyCallableModule(name, factory);
+    queue._getCallableModule(name);
+    queue._getCallableModule(name);
+    expect(factory).toHaveBeenCalledTimes(1);
+  });
 });