fix: Jest mock getAllKeys to return array of keys

Author: matthamil

jest/async-storage-mock.js

@@ -40,7 +40,7 @@ const asMock = {
   ),
 
   clear: jest.fn<[CallbackType], Promise<*>>(_clear),
-  getAllKeys: jest.fn<[], void>(),
+  getAllKeys: jest.fn<[], Promise<string[]>>(_getAllKeys),
   flushGetRequests: jest.fn<[], void>(),
 
   multiGet: jest.fn<[KeysType, ResultCallbackType], Promise<*>>(_multiGet),
@@ -89,6 +89,10 @@ async function _clear(callback: CallbackType) {
   return null;
 }
 
+async function _getAllKeys() {
+  return Object.keys(asMock.__INTERNAL_MOCK_STORAGE__);
+}
+
 async function _multiMerge(
   keyValuePairs: KeyValueType,
   callback: CallbackType,