testCoreDataMergeConflict 2

import XCTest
import CoreData
@testable import iosApp

class iosAppTests: XCTestCase {
    
    func testCoreDataMergeConflict() {
        let expectation = XCTestExpectation(description: "")
        expectation.expectedFulfillmentCount = 2
        
        Task {
            await CoreDataInventory.instance.perform { (context) in
                let newChartState = ChartState(context: context)
                newChartState.chartLen = 100
                newChartState.seed = 1
            }
        }
        
        Task {
            await CoreDataInventory.instance.perform { (context) in
                sleep(1)
                self.modifyChartStateSeed(context, 2)
                sleep(1) // Wait 1 seconds before save for the next background task to read the same version of entity
            }
            expectation.fulfill()
        }
        
        Task {
            await CoreDataInventory.instance.perform { (context) in
                sleep(1)
                self.modifyChartStateSeed(context, 3)
                sleep(2)
            }
            expectation.fulfill()
        }
        
        wait(for: [expectation], timeout: 8)
    }
    
    private func modifyChartStateSeed(_ context: NSManagedObjectContext, _ seed: Int32) {
        let fetchRequest: NSFetchRequest<ChartState> = ChartState.fetchRequest()
        fetchRequest.predicate = NSPredicate(format: "chartLen = %i", 100)
        let chartStateEntity = try? context.fetch(fetchRequest).first
        chartStateEntity?.seed = seed
    }
}