test(query-core): improve test to properly detect duplicate abort listeners

Based on code review feedback, the previous test approach had a flaw:
- Signal destructuring ({signal}) invokes the getter before addEventListener could be spied
- The test was not actually catching duplicate listener registrations

New approach:
- Spy on AbortSignal.prototype.addEventListener before query execution
- Access signal multiple times within queryFn to trigger getter repeatedly
- Verify that only 3 abort listeners are registered (1 per page) instead of 9 (3 per page)

This test now properly validates the memory leak fix and will fail if the
duplicate listener prevention is removed.

Author: kamja44

packages/query-core/src/__tests__/infiniteQueryBehavior.test.tsx

@@ -492,28 +492,27 @@ describe('InfiniteQueryBehavior', () => {
 
   test('should not register duplicate abort event listeners when signal is accessed multiple times', async () => {
     const key = queryKey()
-    let signalAccessCount = 0
-    const listenerCounts: Array<number> = []
 
-    const queryFnSpy = vi.fn().mockImplementation(({ signal }) => {
-      signalAccessCount++
+    // Track addEventListener calls before the query starts
+    const addEventListenerSpy = vi.spyOn(AbortSignal.prototype, 'addEventListener')
+    let previousCallCount = 0
 
-      const originalAddEventListener = signal.addEventListener
-      let currentListenerCount = 0
-      signal.addEventListener = vi.fn((...args) => {
-        currentListenerCount++
-        return originalAddEventListener.apply(signal, args)
-      })
+    const queryFnSpy = vi.fn().mockImplementation((context) => {
+      const currentCallCount = addEventListenerSpy.mock.calls.filter(
+        (call) => call[0] === 'abort'
+      ).length
 
-      // Access signal multiple times to trigger getter
-      signal
-      signal
-      signal
+      // Calculate how many listeners were added for this page
+      const listenersForThisPage = currentCallCount - previousCallCount
+      previousCallCount = currentCallCount
 
-      listenerCounts.push(currentListenerCount)
-      signal.addEventListener = originalAddEventListener
+      // Access signal multiple times to trigger the getter repeatedly
+      // This simulates code that might reference the signal property multiple times
+      context.signal
+      context.signal
+      context.signal
 
-      return `page-${signalAccessCount}`
+      return `page-${listenersForThisPage}`
     })
 
     const observer = new InfiniteQueryObserver(queryClient, {
@@ -527,13 +526,24 @@ describe('InfiniteQueryBehavior', () => {
 
     const unsubscribe = observer.subscribe(() => {})
 
+    // Wait for initial page
     await vi.advanceTimersByTimeAsync(0)
 
+    // Fetch additional pages
     await observer.fetchNextPage()
     await observer.fetchNextPage()
 
-    expect(listenerCounts.every((count) => count <= 1)).toBe(true)
+    // Count total abort listeners registered
+    const totalAbortListeners = addEventListenerSpy.mock.calls.filter(
+      (call) => call[0] === 'abort'
+    ).length
+
+    // With the fix: Each page registers at most 1 abort listener despite signal being accessed 3 times
+    // We fetch 3 pages, so exactly 3 abort listeners
+    // Without the fix: Each signal access registers a listener = 3 accesses × 3 pages = 9 listeners
+    expect(totalAbortListeners).toBe(3)
 
+    addEventListenerSpy.mockRestore()
     unsubscribe()
   })
 })