fix: flaky per resource event source test (#1845)

Author: csviri

operator-framework-core/src/main/java/io/javaoperatorsdk/operator/processing/event/source/polling/PerResourcePollingEventSource.java

@@ -149,7 +149,7 @@ public void run() {
       var primary = resourceCache.get(primaryID);
       if (primary.isEmpty()) {
         log.warn("No resource in cache for resource ID: {}", primaryID);
-        // no new execution is scheduled in this case, a on delete event should be received shortly
+        // no new execution is scheduled in this case, an on delete event should be received shortly
       } else {
         var actualResources = primary.map(p -> getAndCacheResource(p, false));
         scheduleNextExecution(primary.get(), actualResources.orElse(null));

operator-framework-core/src/test/java/io/javaoperatorsdk/operator/processing/event/source/polling/PerResourcePollingEventSourceTest.java

@@ -172,11 +172,12 @@ void deleteEventCancelsTheScheduling() {
             .pollInterval(Duration.ofMillis(20))
             .untilAsserted(() -> verify(supplier,times(1)).fetchResources(any()));
 
+    when(resourceCache.get(any())).thenReturn(Optional.empty());
     source.onResourceDeleted(testCustomResource);
 
-    // check if not called again.
-    await().pollDelay(Duration.ofMillis(PERIOD))
-            .atMost(Duration.ofMillis((2* PERIOD)))
+    // check if not called again
+    await().pollDelay(Duration.ofMillis(2*PERIOD))
+            .atMost(Duration.ofMillis((4* PERIOD)))
             .untilAsserted(() -> verify(supplier,times(1)).fetchResources(any()));
   }