AssertBusy to allow for the decRefs to be dec-ed to 0

Author: andreidan

server/src/test/java/org/elasticsearch/search/SearchServiceSingleNodeTests.java

@@ -3010,18 +3010,19 @@ public void testFetchPhaseAccountsForSourceMemoryUsage() throws Exception {
                 .get();
             if (fetchSearchResult != null) {
                 long usedBeforeResultDecRef = breaker.getUsed();
-                if (fetchSearchResult.decRef()) {
-                    assertThat(usedBeforeResultDecRef, greaterThanOrEqualTo(48_000L));
-                    // when releasing the result references we should clear at least 48_000 bytes (48 hits with sources of at least 1000
-                    // bytes)
+                fetchSearchResult.decRef();
+                assertBusy(() -> {
                     long usedAfterResultDecRef = breaker.getUsed();
                     logger.info(
                         "--> usedBeforeResultDecRef: [{}], usedAfterResultDecRef: [{}]",
                         usedBeforeResultDecRef,
                         usedAfterResultDecRef
                     );
+                    assertThat(usedBeforeResultDecRef, greaterThanOrEqualTo(48_000L));
+                    // when releasing the result references we should clear at least 48_000 bytes (48 hits with sources of at least 1000
+                    // bytes)
                     assertThat(usedBeforeResultDecRef - usedAfterResultDecRef, greaterThanOrEqualTo(48_000L));
-                }
+                });
             }
         }
     }