From eb3c96e7b183642f4624c2148e6fcc5fca298e1d Mon Sep 17 00:00:00 2001
From: Andrew Kushnir <akushnir@google.com>
Date: Tue, 10 May 2022 15:20:05 -0700
Subject: [PATCH] test(core): reset Testability getter after each test (#45947)

This commit updates the Testability-related tests to reset the testability getter class after each test to avoid leaking the state between tests. This should improve the stability of the testability tests that are currently flaky on CI.

PR Close #45947
---
 .../core/test/testability/testability_spec.ts | 20 ++++++++++++++++++-
 1 file changed, 19 insertions(+), 1 deletion(-)

diff --git a/packages/core/test/testability/testability_spec.ts b/packages/core/test/testability/testability_spec.ts
index 7b506c55299..3db749d48ae 100644
--- a/packages/core/test/testability/testability_spec.ts
+++ b/packages/core/test/testability/testability_spec.ts
@@ -12,6 +12,7 @@ import {GetTestability, PendingMacrotask, Testability, TestabilityRegistry} from
 import {NgZone} from '@angular/core/src/zone/ng_zone';
 import {fakeAsync, flush, tick, waitForAsync} from '@angular/core/testing';
 
+import {setTestabilityGetter} from '../../src/testability/testability';
 import {scheduleMicroTask} from '../../src/util/microtask';
 
 // Schedules a microtasks (using a resolved promise .then())
@@ -69,7 +70,15 @@ class MockNgZone extends NgZone {
       execute2 = jasmine.createSpy('execute');
       updateCallback = jasmine.createSpy('execute');
     }));
-
+    afterEach(() => {
+      // Instantiating the Testability (via `new Testability` above) has a side
+      // effect of defining the testability getter globally to a specified value.
+      // This call resets that reference after each test to make sure it does not
+      // get leaked between tests. In real scenarios this is not a problem, since
+      // the `Testability` is created via DI and uses the same testability getter
+      // (injected into a constructor) across all instances.
+      setTestabilityGetter(null! as GetTestability);
+    });
     describe('Pending count logic', () => {
       it('should start with a pending count of 0', () => {
         expect(testability.getPendingRequestCount()).toEqual(0);
@@ -378,6 +387,15 @@ class MockNgZone extends NgZone {
       testability1 = new Testability(ngZone, registry, new NoopGetTestability());
       testability2 = new Testability(ngZone, registry, new NoopGetTestability());
     }));
+    afterEach(() => {
+      // Instantiating the Testability (via `new Testability` above) has a side
+      // effect of defining the testability getter globally to a specified value.
+      // This call resets that reference after each test to make sure it does not
+      // get leaked between tests. In real scenarios this is not a problem, since
+      // the `Testability` is created via DI and uses the same testability getter
+      // (injected into a constructor) across all instances.
+      setTestabilityGetter(null! as GetTestability);
+    });
     describe('unregister testability', () => {
       it('should remove the testability when unregistering an existing testability', () => {
         registry.registerApplication('testability1', testability1);