Chore: Fix playlist flaky test (#114241)

public/app/features/playlist/PlaylistNewPage.test.tsx

@@ -24,7 +24,21 @@ jest.mock('app/core/components/TagFilter/TagFilter', () => ({
 
 function getTestContext() {
   jest.clearAllMocks();
-  const backendSrvMock = jest.spyOn(backendSrv, 'fetch').mockImplementation(() => of(createFetchResponse({})));
+
+  // Create separate spies for different HTTP methods
+  const postSpy = jest.fn();
+  const otherSpy = jest.fn();
+
+  const backendSrvMock = jest.spyOn(backendSrv, 'fetch').mockImplementation((options) => {
+    if (options.method === 'POST') {
+      postSpy(options);
+      return of(createFetchResponse({}));
+    }
+    // Handle GET and other methods
+    otherSpy(options);
+    return of(createFetchResponse({ items: [] }));
+  });
+
   jest.spyOn(backendSrv, 'search').mockResolvedValue([]);
 
   const { rerender } = render(
@@ -33,7 +47,7 @@ function getTestContext() {
     </TestProvider>
   );
 
-  return { rerender, backendSrvMock };
+  return { rerender, backendSrvMock, postSpy, otherSpy };
 }
 
 describe('PlaylistNewPage', () => {
@@ -47,15 +61,17 @@ describe('PlaylistNewPage', () => {
 
   describe('when submitted', () => {
     it('then correct api should be called', async () => {
-      const { backendSrvMock } = getTestContext();
+      const { postSpy } = getTestContext();
 
       expect(locationService.getLocation().pathname).toEqual('/');
 
       await userEvent.type(screen.getByRole('textbox', { name: selectors.pages.PlaylistForm.name }), 'A new name');
       fireEvent.submit(screen.getByRole('button', { name: /save/i }));
-      await waitFor(() => expect(backendSrvMock).toHaveBeenCalledTimes(1));
-      expect(backendSrvMock).toHaveBeenCalledWith(
+      await waitFor(() => expect(postSpy).toHaveBeenCalledTimes(1));
+
+      expect(postSpy).toHaveBeenCalledWith(
         expect.objectContaining({
+          method: 'POST',
           body: expect.objectContaining({
             spec: {
               title: 'A new name',