我在单元测试中尝试用SwiftData加载模型数据时，遇到了一个运行时“错误”，难以解决。

我在MainActor上使用makeModelContext函数来创建一个内存中的模型上下文：

/// Create an in-memory ModelContext containing all app models for testing.
/// This mirrors the models registered in the App's ModelContainer.
@MainActor static func makeModelContext() throws -> ModelContext {
    // Use an in-memory model configuration for tests to avoid CloudKit/SwiftData background
    // registration collisions with the app's shared ModelContainer.
    let config = ModelConfiguration(isStoredInMemoryOnly: true)
    let schema = Schema([
        Car.self,
        Charger.self,
        ChargingCostPlan.self,
        ChargingSession.self,
        ChargingSessionTemplate.self,
        PriceElement.self,
        Location.self,
        HomeConsumption.self
    ])
    let container = try ModelContainer(for: schema, configurations: [config])
    // Disable autosave to avoid background persistence during tests
    container.mainContext.autosaveEnabled = false

    return container.mainContext
}

在我的测试函数中，我也在MainActor中调用makeModelContext函数：

@Test("Import a representative subset of the backup JSON")
@MainActor
func testImportRepresentativeSubset() async throws {
    // Locate the test data JSON next to this test file
    let testFileURL = URL(fileURLWithPath: #file).deletingLastPathComponent().appendingPathComponent("TestData_2026-03-07.json")
    let raw = try Data(contentsOf: testFileURL)

    let decoder = JSONDecoder()
    decoder.dateDecodingStrategy = .iso8601
    let backup = try decoder.decode(DataEncoder.Backup.self, from: raw)

    let encoder = JSONEncoder()
    encoder.outputFormatting = [.prettyPrinted, .sortedKeys]
    encoder.dateEncodingStrategy = .iso8601
    let data = try encoder.encode(backup)

    // Create an in-memory ModelContext (helper provided by test infra)
    let modelContext = try TestHelpers.makeModelContext()
    modelContext.autosaveEnabled = false

    // Import
    let report = try DataImporter.importFrom(data: data, into: modelContext)

    ...

在上述代码的最后一行，我把测试函数中的这个modelContext传递给待测试的函数：

/// Import from raw JSON Data (the shape produced by `DataEncoder.Backup`).
/// - Parameters:
///   - data: JSON data produced by `DataEncoder.export`
///   - modelContext: the SwiftData `ModelContext` to insert objects into
/// - Returns: an import report summarising the operation.
@MainActor
public static func importFrom(data: Data, into modelContext: ModelContext) throws -> DataImportReport {
    var report = DataImportReport()

    let decoder = JSONDecoder()
    decoder.dateDecodingStrategy = .iso8601

    do {
        let backup = try decoder.decode(DataEncoder.Backup.self, from: data)

        // Prefetch existing objects once to avoid repeated fetches and actor issues
        let existingCars: [Car] = (try? modelContext.fetch(FetchDescriptor<Car>())) ?? []
    ...

在上述代码的最后一行，我收到了以下运行时信息，测试过程因此停止：

Task 55: EXC_BREAKPOINT (code=1, subcode=0x1d9d2a8b4)

我尝试通过网络搜索、Github Copilot和 Xcode Coding Assistant来寻求解决方案，但没有一个建议有帮助。我检查了以下几点：

• 模型注册已完成
• modelContext有效
• 谓词有效

有什么建议，可能的根本原因是什么？

解决方案

问题在于内存中的modelContext的容器被释放了。这篇帖子给出了一个解决方案：

SwiftData单元测试在插入时的EXC_BREAKPOINT