[CI] Random test failure with test_loadReplies_whenIsFirstPage_shouldClearCurrentMessagesExcludingLocalOnly

Sources/StreamChat/Database/DatabaseContainer.swift

@@ -252,6 +252,21 @@ class DatabaseContainer: NSPersistentContainer {
         }
     }
 
+    func read<T>(_ actions: @escaping (DatabaseSession) throws -> T, completion: @escaping (Result<T, Error>) -> Void) {
+        let context = backgroundReadOnlyContext
+        context.perform {
+            do {
+                let results = try actions(context)
+                if context.hasChanges {
+                    assertionFailure("Background context is read only, but calling actions() created changes")
+                }
+                completion(.success(results))
+            } catch {
+                completion(.failure(error))
+            }
+        }
+    }
+
     @available(iOS 13.0, *)
     func write(_ actions: @escaping (DatabaseSession) throws -> Void) async throws {
         try await withCheckedThrowingContinuation { (continuation: CheckedContinuation<Void, Error>) in

TestTools/StreamChatTestTools/SpyPattern/Spy/DatabaseContainer_Spy.swift

@@ -130,6 +130,19 @@ public final class DatabaseContainer_Spy: DatabaseContainer, Spy {
 }
 
 extension DatabaseContainer {
+    /// Reads changes from the DB synchronously. Only for test purposes!
+    func readSynchronously<T>(_ actions: @escaping (DatabaseSession) throws -> T) throws -> T {
+        let result = try waitFor { completion in
+            self.read(actions, completion: completion)
+        }
+        switch result {
+        case .success(let values):
+            return values
+        case .failure(let error):
+            throw error
+        }
+    }
+
     /// Writes changes to the DB synchronously. Only for test purposes!
     func writeSynchronously(_ actions: @escaping (DatabaseSession) throws -> Void) throws {
         let error = try waitFor { completion in

Tests/StreamChatTests/Workers/MessageUpdater_Tests.swift

@@ -2783,6 +2783,14 @@ extension MessageUpdater_Tests {
         line: UInt = #line,
         file: StaticString = #filePath
     ) throws {
+        func showsInsideThread(messageIds: [MessageId]) throws -> [Bool] {
+            try database.readSynchronously { session in
+                messageIds
+                    .compactMap { session.message(id: $0) }
+                    .map(\.showInsideThread)
+            }
+        }
+
         let parentMessageId = MessageId.unique
         let currentUserId: UserId = .unique
         let currentMessageIds: [MessageId] = [.unique, .unique, .unique]
@@ -2811,11 +2819,7 @@ extension MessageUpdater_Tests {
             }
         }
 
-        var currentMessageDTOs: [MessageDTO] {
-            currentMessageIds.compactMap { database.viewContext.message(id: $0) }
-        }
-
-        XCTAssertEqual(currentMessageDTOs.map(\.showInsideThread), [true, true, true])
+        try XCTAssertEqual(showsInsideThread(messageIds: currentMessageIds), [true, true, true])
 
         // Simulate `loadReplies` call
         let exp = expectation(description: "should load replies")
@@ -2831,19 +2835,30 @@ extension MessageUpdater_Tests {
 
         waitForExpectations(timeout: defaultTimeout)
 
-        var newMessageDTOs: [MessageDTO] {
-            messageIds.compactMap { database.viewContext.message(id: $0) }
-        }
-
         if shouldClear {
             // Previous current messages are not shown (excluding local messages).
-            XCTAssertEqual(currentMessageDTOs.filter { $0.showInsideThread }.count, 1, file: file, line: line)
+            try XCTAssertEqual(
+                showsInsideThread(messageIds: currentMessageIds).filter { $0 }.count,
+                1,
+                file: file,
+                line: line
+            )
         } else {
             // Previous current messages are not discarded.
-            XCTAssertEqual(currentMessageDTOs.map(\.showInsideThread), [true, true, true], file: file, line: line)
+            try XCTAssertEqual(
+                showsInsideThread(messageIds: currentMessageIds),
+                [true, true, true],
+                file: file,
+                line: line
+            )
         }
 
         // Newly fetched messages are shown.
-        XCTAssertEqual(newMessageDTOs.map(\.showInsideThread), [true, true, true], file: file, line: line)
+        try XCTAssertEqual(
+            showsInsideThread(messageIds: messageIds),
+            [true, true, true],
+            file: file,
+            line: line
+        )
     }
 }