Fix user.become for AsyncStorage

src/ParseUser.js

@@ -891,16 +891,15 @@ const DefaultController = {
     return Storage.removeItemAsync(path);
   },
 
-  setCurrentUser(user) {
-    const currentUser = this.currentUser();
-    let promise = Promise.resolve();
+  async setCurrentUser(user) {
+    const currentUser = await this.currentUserAsync();
     if (currentUser && !user.equals(currentUser) && AnonymousUtils.isLinked(currentUser)) {
-      promise = currentUser.destroy({ sessionToken: currentUser.getSessionToken() })
+      await currentUser.destroy({ sessionToken: currentUser.getSessionToken() })
     }
     currentUserCache = user;
     user._cleanupAuthData();
     user._synchronizeAllAuthData();
-    return promise.then(() => DefaultController.updateUserOnDisk(user));
+    return DefaultController.updateUserOnDisk(user);
   },
 
   currentUser(): ?ParseUser {

src/__tests__/ParseUser-test.js

@@ -35,7 +35,9 @@ jest.mock('uuid/v4', () => {
   return () => value++;
 });
 jest.dontMock('./test_helpers/mockXHR');
+jest.dontMock('./test_helpers/mockAsyncStorage');
 
+const mockAsyncStorage = require('./test_helpers/mockAsyncStorage');
 const CoreManager = require('../CoreManager');
 const CryptoController = require('../CryptoController');
 const LocalDatastore = require('../LocalDatastore');
@@ -299,6 +301,34 @@ describe('ParseUser', () => {
     });
   });
 
+  it('can become a user with async storage', async () => {
+    const currentStorage = CoreManager.getStorageController();
+    CoreManager.setStorageController(mockAsyncStorage);
+    ParseUser.enableUnsafeCurrentUser();
+    ParseUser._clearCache();
+    CoreManager.setRESTController({
+      request(method, path, body, options) {
+        expect(method).toBe('GET');
+        expect(path).toBe('users/me');
+        expect(options.sessionToken).toBe('123abc');
+
+        return Promise.resolve({
+          objectId: 'uid3',
+          username: 'username',
+          sessionToken: '123abc'
+        }, 200);
+      },
+      ajax() {}
+    });
+
+    const u = await ParseUser.become('123abc');
+    expect(u.id).toBe('uid3');
+    expect(u.isCurrent()).toBe(true);
+    expect(u.existed()).toBe(true);
+    CoreManager.setStorageController(currentStorage);
+  });
+
+
   it('can hydrate a user with sessionToken in server environment', async () => {
     ParseUser.enableUnsafeCurrentUser();
     ParseUser._clearCache();

src/__tests__/test_helpers/mockAsyncStorage.js

@@ -0,0 +1,25 @@
+let mockStorage = {};
+const mockAsyncStorage = {
+  async: 1,
+  async getItemAsync(path) {
+    return mockStorage[path];
+  },
+
+  async setItemAsync(path, value) {
+    mockStorage[path] = value;
+  },
+
+  async removeItemAsync(path) {
+    delete mockStorage[path];
+  },
+
+  async getAllKeysAsync() {
+    return Object.keys(mockStorage);
+  },
+
+  clear() {
+    mockStorage = {};
+  },
+};
+
+module.exports = mockAsyncStorage;