test: Remove mock so that future tests will not be affected by the mock (#1099)

* Ensure the mock isn’t permanent for other cases

Reassign this mock back to what it was because future tests will rely on this being the proper value.

* Add async to verify the change works

Async will run all the tests twice failing if the prior change was not implemented.

* Revert "Add async to verify the change works"

This reverts commit 57855a3.

* Adjust the comment slightly

Adjust the comment slightly to address the fact that we are changing the mocked function back to the way it was.

* Refactor the mock out into a constant

The mock should be a constant instead of repeating a code fragment that must be the same.

* Surround with try/finally

We can use try/finally so that even if the test fails the mock gets reset.

* Revert "Surround with try/finally"

This reverts commit 73bea28.

* Have a fake entity init state

Have a fake entity init state and then before each test initialize the fakeEntity from the fakeEntityInit state.

* Remove resetting the mock in individual tests

Now that we initialize the fake entity at the beginning of every single test, we do not need to reset the mock in that one test anymore.

* Eliminate unused variable

Variable is not used anymore so should be eliminated from the code change.

Author: danieljbruce

test/index.ts

@@ -30,7 +30,7 @@ import * as extend from 'extend';
 const v1 = require('../src/v1/index.js');
 
 // eslint-disable-next-line @typescript-eslint/no-explicit-any
-const fakeEntity: any = {
+const fakeEntityInit: any = {
   KEY_SYMBOL: Symbol('fake key symbol'),
   Int: class {
     value: {};
@@ -82,6 +82,8 @@ const fakeEntity: any = {
   URLSafeKey: entity.URLSafeKey,
 };
 
+const fakeEntity: any = {};
+
 let googleAuthOverride: Function | null;
 function fakeGoogleAuth(...args: Array<{}>) {
   return (googleAuthOverride || (() => {}))(...args);
@@ -157,6 +159,7 @@ describe('Datastore', () => {
   };
 
   before(() => {
+    Object.assign(fakeEntity, fakeEntityInit);
     Datastore = proxyquire('../src', {
       './entity.js': {entity: fakeEntity},
       './index-class.js': {Index: FakeIndex},
@@ -171,6 +174,8 @@ describe('Datastore', () => {
   });
 
   beforeEach(() => {
+    Object.assign(fakeEntity, fakeEntityInit);
+
     createInsecureOverride = null;
     googleAuthOverride = null;