iOS17+ fix: Move data refresh from viewDidLoad to new ViewControlle…

…r's `viewIsAppearing` lifecycle method

- This change is needed since UIRefreshControl updates must happen when the view is on-screen on iOS17+ (it ignores updates otherwise!).

- `viewDidLoad` is called once per VC, but the new `viewIsAppearing` may be called multiple times - so we added logic to ensure the refresh only happens in the first `viewIsAppearing` occurrence to mimic the previous behavior in `viewDidLoad`.

- When running tests, the views are never added on-screen, so UIRefreshControl doesn't work as expected on iOS 17+. To allow testability, we replace the UIRefreshControl with a UIRefreshControlSpy test-double.

EssentialApp/EssentialAppTests/CommentsUIIntegrationTests.swift

@@ -14,17 +14,17 @@ class CommentsUIIntegrationTests: XCTestCase {
 	func test_commentsView_hasTitle() {
 		let (sut, _) = makeSUT()
 
-		sut.loadViewIfNeeded()
+		sut.simulateAppearance()
 
 		XCTAssertEqual(sut.title, commentsTitle)
 	}
 
 	func test_loadCommentsActions_requestCommentsFromLoader() {
 		let (sut, loader) = makeSUT()
-		XCTAssertEqual(loader.loadCommentsCallCount, 0, "Expected no loading requests before view is loaded")
+		XCTAssertEqual(loader.loadCommentsCallCount, 0, "Expected no loading requests before view appears")
 
-		sut.loadViewIfNeeded()
-		XCTAssertEqual(loader.loadCommentsCallCount, 1, "Expected a loading request once view is loaded")
+		sut.simulateAppearance()
+		XCTAssertEqual(loader.loadCommentsCallCount, 1, "Expected a loading request once view appears")
 
 		sut.simulateUserInitiatedReload()
 		XCTAssertEqual(loader.loadCommentsCallCount, 1, "Expected no request until previous completes")
@@ -38,11 +38,22 @@ class CommentsUIIntegrationTests: XCTestCase {
 		XCTAssertEqual(loader.loadCommentsCallCount, 3, "Expected yet another loading request once user initiates another reload")
 	}
 
+	func test_loadCommentsActions_runsAutomaticallyOnlyOnFirstAppearance() {
+		let (sut, loader) = makeSUT()
+		XCTAssertEqual(loader.loadCommentsCallCount, 0, "Expected no loading requests before view appears")
+
+		sut.simulateAppearance()
+		XCTAssertEqual(loader.loadCommentsCallCount, 1, "Expected a loading request once view appears")
+
+		sut.simulateAppearance()
+		XCTAssertEqual(loader.loadCommentsCallCount, 1, "Expected no loading request the second time view appears")
+	}
+
 	func test_loadingCommentsIndicator_isVisibleWhileLoadingComments() {
 		let (sut, loader) = makeSUT()
 
-		sut.loadViewIfNeeded()
-		XCTAssertTrue(sut.isShowingLoadingIndicator, "Expected loading indicator once view is loaded")
+		sut.simulateAppearance()
+		XCTAssertTrue(sut.isShowingLoadingIndicator, "Expected loading indicator once view appears")
 
 		loader.completeCommentsLoading(at: 0)
 		XCTAssertFalse(sut.isShowingLoadingIndicator, "Expected no loading indicator once loading completes successfully")
@@ -59,7 +70,7 @@ class CommentsUIIntegrationTests: XCTestCase {
 		let comment1 = makeComment(message: "another message", username: "another username")
 		let (sut, loader) = makeSUT()
 
-		sut.loadViewIfNeeded()
+		sut.simulateAppearance()
 		assertThat(sut, isRendering: [ImageComment]())
 
 		loader.completeCommentsLoading(with: [comment0], at: 0)
@@ -74,7 +85,7 @@ class CommentsUIIntegrationTests: XCTestCase {
 		let comment = makeComment()
 		let (sut, loader) = makeSUT()
 
-		sut.loadViewIfNeeded()
+		sut.simulateAppearance()
 		loader.completeCommentsLoading(with: [comment], at: 0)
 		assertThat(sut, isRendering: [comment])
 
@@ -87,7 +98,7 @@ class CommentsUIIntegrationTests: XCTestCase {
 		let comment = makeComment()
 		let (sut, loader) = makeSUT()
 
-		sut.loadViewIfNeeded()
+		sut.simulateAppearance()
 		loader.completeCommentsLoading(with: [comment], at: 0)
 		assertThat(sut, isRendering: [comment])
 
@@ -98,7 +109,7 @@ class CommentsUIIntegrationTests: XCTestCase {
 
 	func test_loadCommentsCompletion_dispatchesFromBackgroundToMainThread() {
 		let (sut, loader) = makeSUT()
-		sut.loadViewIfNeeded()
+		sut.simulateAppearance()
 
 		let exp = expectation(description: "Wait for background queue")
 		DispatchQueue.global().async {
@@ -111,7 +122,7 @@ class CommentsUIIntegrationTests: XCTestCase {
 	func test_loadCommentsCompletion_rendersErrorMessageOnErrorUntilNextReload() {
 		let (sut, loader) = makeSUT()
 
-		sut.loadViewIfNeeded()
+		sut.simulateAppearance()
 		XCTAssertEqual(sut.errorMessage, nil)
 
 		loader.completeCommentsLoadingWithError(at: 0)
@@ -124,7 +135,7 @@ class CommentsUIIntegrationTests: XCTestCase {
 	func test_tapOnErrorView_hidesErrorMessage() {
 		let (sut, loader) = makeSUT()
 
-		sut.loadViewIfNeeded()
+		sut.simulateAppearance()
 		XCTAssertEqual(sut.errorMessage, nil)
 
 		loader.completeCommentsLoadingWithError(at: 0)
@@ -147,7 +158,7 @@ class CommentsUIIntegrationTests: XCTestCase {
 					}).eraseToAnyPublisher()
 			})
 
-			sut?.loadViewIfNeeded()
+			sut?.simulateAppearance()
 		}
 
 		XCTAssertEqual(cancelCallCount, 0)

EssentialApp/EssentialAppTests/FeedAcceptanceTests.swift

@@ -91,7 +91,9 @@ class FeedAcceptanceTests: XCTestCase {
 		sut.configureWindow()
 
 		let nav = sut.window?.rootViewController as? UINavigationController
-		return nav?.topViewController as! ListViewController
+		let vc = nav?.topViewController as! ListViewController
+		vc.simulateAppearance()
+		return vc
 	}
 
 	private func enterBackground(with store: InMemoryFeedStore) {
@@ -106,7 +108,9 @@ class FeedAcceptanceTests: XCTestCase {
 		RunLoop.current.run(until: Date())
 
 		let nav = feed.navigationController
-		return nav?.topViewController as! ListViewController
+		let vc = nav?.topViewController as! ListViewController
+		vc.simulateAppearance()
+		return vc
 	}
 
 	private func response(for url: URL) -> (Data, HTTPURLResponse) {