EntityFramework，DbContextScope和Effort - 異常：DbContext已被置於單元測試中

Question

EntityFramework，DbContextScope和Effort - 異常：DbContext已被置於單元測試中

c# dbcontext effort entity-framework unit-testing

題

我正在嘗試為服務層編寫單元測試（使用NUnit），該服務層使用：

實體框架作為數據訪問層
DbContextScope管理的DbContext一生

我還使用Effort.EF6在單元測試中模擬DbContext。不幸的是，我找不到讓DbContextScope與Effort兼容的方法，以便我可以正確測試所有案例。

代碼概述

服務層由執行某些業務邏輯的類（服務）組成。每個方法都被視為一個完整的事務，以context.SaveChanges()結束。例：

    private IDbContextScopeFactory _dbContextScopeFactory;

    public DepartmentsService(IDbContextScopeFactory dbContextScopeFactory)
    {
        _dbContextScopeFactory = dbContextScopeFactory;
    }

    public BusinessModel.Department Insert(BusinessModel.Department department)
    {
        using (var dbContextScope = _dbContextScopeFactory.Create())
        {
            // Validation
            ValidateAndThrowOnFailure(department, new DepartmentAddValidator());

            // Operation
            DBModel.Department newDepartment = Mapper.Map<DBModel.Department>(department);

            newDepartment.InsertDateUTC = DateTime.UtcNow;

            dbContextScope.DbContexts.Get<DPSContext>().Departments.Add(newDepartment);
            dbContextScope.SaveChanges();

            return Mapper.Map<BusinessModel.Department>(newDepartment);
        }
    }

為了對這種方法進行單元測試，我在每次測試前做了一些準備：

    private IDepartmentsService _departmentsService;
    private IDbContextScopeFactory _dbContextScopeFactory;
    private IDbContextFactory _dbContextFactory;
    private DBModel.DPSContext _dbEntities;

    [SetUp]
    public void ReInitializeTest()
    {
        // Setup DbContext with Effort.EF6
        string connStr = ConfigurationManager.ConnectionStrings["DPSContext"].ConnectionString;
        DbConnection connection = EntityConnectionFactory.CreateTransient(connStr);
        _dbEntities = new DBModel.DPSContext(connection);

        // Fill DbContext with in-memory data
        _dbEntities.Departments.AddRange(DataInitializer.GetDepartments());
        _dbEntities.SaveChanges();

        // Mock IDbContextFactory so that it returns in-memory context
        var contextFactoryMock = new Mock<IDbContextFactory>();

        contextFactoryMock
            .Setup(f => f.CreateDbContext<DBModel.DPSContext>())
            .Returns(_dbEntities);

        _dbContextFactory = contextFactoryMock.Object;

        // Setup DbContextScopeFactory to use mocked context
        _dbContextScopeFactory = new DbContextScopeFactory(_dbContextFactory);
        _departmentsService = new DepartmentsService(_dbContextScopeFactory);
    }

測試和問題

這是一個簡單的單元測試：

    [Test]
    public void Insert_WhenValidModelPassed_ShouldInsertNewRecord()
    {
        // Given
        BusinessModel.Department newDepartment = DataInitializer.GetExampleOfNewDepartment();

        // When
        _departmentsService.Insert(newDepartment);

        // Then
        Assert.AreEqual(3, _dbEntities.Departments.Count());
    }

問題是測試失敗，但有異常：

System.InvalidOperationException : The operation cannot be completed because the DbContext has been disposed.

似乎在Insert方法內部使用的DbContextScope內部在using塊的末尾處理分配的上下文，因此Assert在調用時拋出異常。有沒有人遇到類似的問題，或者只是知道我應該做些什麼來成功測試這個和類似的場景？

PJDev

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Accepted Answer

對於遇到類似問題的人，我創建了一個有點臟但工作的解決方案（至少我希望如此）。除了我在問題中寫的內容之外，我創建了一個派生自真實上下文的類，並使Dispose方法做到了......沒有。我還添加了一個RealDispose方法，該方法在每次測試結束時調用。

    public class TestableDPSContext : DBModel.DPSContext
    {
        public TestableDPSContext(DbConnection connection)
            : base(connection)
        {

        }

        protected override void Dispose(bool disposing)
        {
            // Do nothing
        }

        public void RealDispose(bool disposing)
        {
            // Invoke real dispose
            base.Dispose(disposing);
        }
    }

    [TearDown]
    public void FinishTest()
    {
        _dbEntities.RealDispose(false);
    }

也許有一個更好的解決方案，但是現在它似乎解決了DbContext在測試中處理得太早的問題。

EntityFramework，DbContextScope和Effort - 異常：DbContext已被置於單元測試中

題

一般承認的答案

Performance

Expression Evaluator