fix(cdk/testing): prevent duplicate subscription (#22460)

bgotink · mmalerba · commit a9e5ad264a08 · 2021-04-13T10:11:45.000-07:00
If the actual subscription provided by the environment comes after the first batched function call, the default function is installed and without this change it'll stay installed forever, even if another handler is installed afterwards. (cherry picked from commit 58b4ab6)
diff --git a/src/cdk/testing/change-detection.ts b/src/cdk/testing/change-detection.ts
@@ -69,7 +69,7 @@ async function batchChangeDetection<T>(fn: () => Promise<T>, triggerBeforeAndAft
 
   // If nothing is handling change detection batching, install the default handler.
   if (!autoChangeDetectionSubscription) {
-    autoChangeDetectionSubject.subscribe(defaultAutoChangeDetectionHandler);
+    handleAutoChangeDetectionStatus(defaultAutoChangeDetectionHandler);
   }
 
   if (triggerBeforeAndAfter) {

Original file line number	Diff line number	Diff line change
`@@ -69,7 +69,7 @@ async function batchChangeDetection<T>(fn: () => Promise<T>, triggerBeforeAndAft`
`69`	`69`
`70`	`70`	`// If nothing is handling change detection batching, install the default handler.`
`71`	`71`	`if (!autoChangeDetectionSubscription) {`
`72`		`- autoChangeDetectionSubject.subscribe(defaultAutoChangeDetectionHandler);`
	`72`	`+ handleAutoChangeDetectionStatus(defaultAutoChangeDetectionHandler);`
`73`	`73`	`}`
`74`	`74`
`75`	`75`	`if (triggerBeforeAndAfter) {`