Fix oppia#23278 CI frontend test failures in image-preloader.service.spec.ts (oppia#23618)

* fixed flake

* fixed flake

---------

Co-authored-by: Mohit Ruwatia <120438312+mon4our@users.noreply.github.com>

Author: KartikSuryavanshi

core/templates/pages/exploration-player-page/services/image-preloader.service.spec.ts

@@ -384,6 +384,16 @@ describe('Image preloader service', () => {
 
   let exploration: Exploration;
 
+  // Helper to flush platform feature-flags evaluation request if present.
+  const flushFeatureFlagsIfQueued = () => {
+    const featureFlagsReq = httpTestingController.match(req =>
+      req.url.includes('/feature_flags_evaluation_handler')
+    );
+    if (featureFlagsReq && featureFlagsReq.length) {
+      featureFlagsReq.forEach(req => req.flush({}));
+    }
+  };
+
   beforeEach(() => {
     imagePreloaderService = TestBed.get(ImagePreloaderService);
     pageContextService = TestBed.get(PageContextService);
@@ -413,6 +423,8 @@ describe('Image preloader service', () => {
     imagePreloaderService.init(exploration);
     imagePreloaderService.kickOffImagePreloader(initStateName);
 
+    flushFeatureFlagsIfQueued();
+
     expect(imagePreloaderService.inExplorationPlayer()).toBeTruthy();
 
     httpTestingController.expectOne(requestUrl1);
@@ -428,13 +440,7 @@ describe('Image preloader service', () => {
     imagePreloaderService.init(exploration);
     imagePreloaderService.kickOffImagePreloader(initStateName);
 
-    // Flush feature flags request to avoid open request error in CI.
-    const featureFlagsReq = httpTestingController.match(req =>
-      req.url.includes('/feature_flags_evaluation_handler')
-    );
-    if (featureFlagsReq && featureFlagsReq.length) {
-      featureFlagsReq.forEach(req => req.flush({}));
-    }
+    flushFeatureFlagsIfQueued();
 
     // Max files to download simultaneously is 3.
     httpTestingController.expectOne(requestUrl1).flush(imageBlob);
@@ -483,6 +489,8 @@ describe('Image preloader service', () => {
     imagePreloaderService.init(exploration);
     imagePreloaderService.kickOffImagePreloader(initStateName);
 
+    flushFeatureFlagsIfQueued();
+
     httpTestingController.expectOne(requestUrl1);
     httpTestingController.expectOne(requestUrl2);
     httpTestingController.expectOne(requestUrl3);
@@ -506,6 +514,8 @@ describe('Image preloader service', () => {
       imagePreloaderService.init(exploration);
       imagePreloaderService.kickOffImagePreloader(initStateName);
 
+      flushFeatureFlagsIfQueued();
+
       httpTestingController.expectOne(requestUrl1);
       httpTestingController.expectOne(requestUrl2);
       httpTestingController.expectOne(requestUrl3);
@@ -535,6 +545,8 @@ describe('Image preloader service', () => {
       imagePreloaderService.init(exploration);
       imagePreloaderService.kickOffImagePreloader(initStateName);
 
+      flushFeatureFlagsIfQueued();
+
       httpTestingController.expectOne(requestUrl1).flush(imageBlob);
       httpTestingController.expectOne(requestUrl2).flush(imageBlob);
       httpTestingController.expectOne(requestUrl3).flush(imageBlob);
@@ -569,13 +581,7 @@ describe('Image preloader service', () => {
       imagePreloaderService.kickOffImagePreloader(initStateName);
       flushMicrotasks();
 
-      // Flush feature flags request to avoid open request error in CI.
-      const featureFlagsReq = httpTestingController.match(req =>
-        req.url.includes('/feature_flags_evaluation_handler')
-      );
-      if (featureFlagsReq && featureFlagsReq.length) {
-        featureFlagsReq.forEach(req => req.flush({}));
-      }
+      flushFeatureFlagsIfQueued();
 
       expect(
         imagePreloaderService.getFilenamesOfImageCurrentlyDownloading()
@@ -607,13 +613,7 @@ describe('Image preloader service', () => {
     imagePreloaderService.init(exploration);
     imagePreloaderService.kickOffImagePreloader(initStateName);
 
-    // Flush feature flags request to avoid open request error in CI.
-    const featureFlagsReq = httpTestingController.match(req =>
-      req.url.includes('/feature_flags_evaluation_handler')
-    );
-    if (featureFlagsReq && featureFlagsReq.length) {
-      featureFlagsReq.forEach(req => req.flush({}));
-    }
+    flushFeatureFlagsIfQueued();
 
     httpTestingController.expectOne(requestUrl1).flush(imageBlob);
     httpTestingController.expectOne(requestUrl2).flush(imageBlob);
@@ -651,6 +651,8 @@ describe('Image preloader service', () => {
     imagePreloaderService.init(exploration);
     imagePreloaderService.kickOffImagePreloader(initStateName);
 
+    flushFeatureFlagsIfQueued();
+
     httpTestingController.expectOne(requestUrl1);
     httpTestingController.expectOne(requestUrl2);
     httpTestingController.expectOne(requestUrl3);
@@ -692,6 +694,8 @@ describe('Image preloader service', () => {
     imagePreloaderService.init(exploration);
     imagePreloaderService.kickOffImagePreloader(initStateName);
 
+    flushFeatureFlagsIfQueued();
+
     httpTestingController.expectOne(requestUrl1).flush(imageBlob);
     httpTestingController.expectOne(requestUrl2);
     httpTestingController.expectOne(requestUrl3);
@@ -730,6 +734,8 @@ describe('Image preloader service', () => {
     imagePreloaderService.init(exploration);
     imagePreloaderService.kickOffImagePreloader(initStateName);
 
+    flushFeatureFlagsIfQueued();
+
     httpTestingController
       .expectOne(requestUrl1)
       .flush(new Blob(['svg image'], {type: 'image/svg+xml'}));
@@ -775,6 +781,8 @@ describe('Image preloader service', () => {
       imagePreloaderService.init(exploration);
       imagePreloaderService.kickOffImagePreloader(initStateName);
 
+      flushFeatureFlagsIfQueued();
+
       httpTestingController
         .expectOne(requestUrl1)
         .flush(imageBlob, {status: 404, statusText: 'Status Text'});
@@ -819,13 +827,7 @@ describe('Image preloader service', () => {
     imagePreloaderService.init(exploration);
     imagePreloaderService.kickOffImagePreloader(initStateName);
 
-    // Flush feature flags request to avoid open request error in CI.
-    const featureFlagsReq = httpTestingController.match(req =>
-      req.url.includes('/feature_flags_evaluation_handler')
-    );
-    if (featureFlagsReq && featureFlagsReq.length) {
-      featureFlagsReq.forEach(req => req.flush({}));
-    }
+    flushFeatureFlagsIfQueued();
 
     httpTestingController
       .expectOne(requestUrl1)
@@ -869,6 +871,8 @@ describe('Image preloader service', () => {
       imagePreloaderService.init(exploration);
       imagePreloaderService.kickOffImagePreloader(initStateName);
 
+      flushFeatureFlagsIfQueued();
+
       var onSuccess = jasmine.createSpy('success');
       var onFailure = jasmine.createSpy('fail');
       // This throws "Argument of type 'mockReaderObject' is not assignable
@@ -909,13 +913,7 @@ describe('Image preloader service', () => {
       imagePreloaderService.init(exploration);
       imagePreloaderService.kickOffImagePreloader(initStateName);
 
-      // Flush feature flags request to avoid open request error in CI.
-      const featureFlagsReq = httpTestingController.match(req =>
-        req.url.includes('/feature_flags_evaluation_handler')
-      );
-      if (featureFlagsReq && featureFlagsReq.length) {
-        featureFlagsReq.forEach(req => req.flush({}));
-      }
+      flushFeatureFlagsIfQueued();
 
       var onSuccess = jasmine.createSpy('success');
       var onFailure = jasmine.createSpy('fail');