单元测试实体框架中的动态查询4

Question

当使用实体框架4.0实现工作单元模式时，使用对象上下文的CreateQuery方法创建动态查询的能力是正确的设计是什么？正确地说，我的意思是以某种方式设计我可以在模拟对象的单元测试中使用它。

谢谢。

Answer 1

不知道“正确”是什么意思取决于你的情况，但一般的答案是你需要一些可以在测试过程中被替换的抽象。对于一些灵感，这里是我们使用（我们用自我跟踪POCO实体）

/// <summary> 
/// Object context interface for abstracting the service layer from the 
/// implementation details of object storage. 
/// </summary> 
public interface IObjectContext : IDisposable 
{ 
    /// <summary> 
    /// Returns the entity objects of the given type known by this object context. 
    /// </summary> 
    /// <typeparam name="TEntity">The type of the entity.</typeparam> 
    /// <returns>The instances of the given type already loaded into this object context</returns> 
    IEnumerable<TEntity> GetManagedEntities<TEntity>() where TEntity : EntityBase; 

    /// <summary> 
    /// Creates an object set for the provided entity type. 
    /// </summary> 
    /// <typeparam name="TEntity">The type of the entity.</typeparam> 
    /// <returns></returns> 
    IObjectSet<TEntity> CreateObjectSet<TEntity>() where TEntity : EntityBase; 

    /// <summary> 
    /// Applies the changes made to the provided entity object graph to this object context. 
    /// </summary> 
    /// <typeparam name="TEntity">The type of entity (inferred).</typeparam> 
    /// <param name="entity">The entity object graph that has been modified.</param> 
    void ApplyChanges<TEntity>(TEntity entity) where TEntity : EntityBase, IObjectWithChangeTracker; 

    /// <summary> 
    /// Saves the changes known by this object context instance to the database. 
    /// </summary> 
    void Save(); 

    /// <summary> 
    /// Creates a new logical unit of work spanning a single business transaction. 
    /// </summary> 
    IUnitOfWork CreateUnitOfWork(); 

    /// <summary> 
    /// Creates a new logical unit of work spanning a single business transaction. 
    /// </summary> 
    /// <param name="isolationLevel">The transaction isolation level used by the 
    /// unit of work ambient transaction.</param> 
    /// <returns></returns> 
    IUnitOfWork CreateUnitOfWork(IsolationLevel isolationLevel); 
} 

以及用于提取交易

/// <summary> 
/// Interface abstraction for a unit of work, aka all persistent work spanning a single 
/// business transaction and to be performed in unity. 
/// </summary> 
/// <remarks>Used to support outer and inner units of work where one outer UoW may consist 
/// of multiple nested inner UoW instances and have all of them share a transaction.</remarks> 
public interface IUnitOfWork : IDisposable 
{ 
    /// <summary> 
    /// Gets the transaction isolation level used by the unit of work ambient transaction. 
    /// </summary> 
    /// <value>The isolation level.</value> 
    IsolationLevel IsolationLevel { get; } 

    /// <summary> 
    /// Gets the transaction timeout time span used by the unit of work ambient transaction. 
    /// </summary> 
    /// <value>The transaction timeout duration.</value> 
    TimeSpan TransactionTimeout { get; } 

    /// <summary> 
    /// Completes the unit of work that this instance represents. 
    /// </summary> 
    /// <remarks> 
    /// For an outer unit of work, will persist all changes represented by this business 
    /// transaction and will then signal the ambient transaction in use as complete. 
    /// For an inner unit of work, will signal itself as completed to the outer unit of 
    /// work that it is part of. 
    /// </remarks> 
    void Complete(); 
} 

然后修改对象上下文生成的代码来支持这些接口+实现你的UOW根据您的需求（为简洁起见，我们省略了实施）。 HTH