利用Mocking Framework 單元測試Entity Framework
阿新 • • 發佈:2017-06-10
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一、前言
在實際編寫程序時,往往需要與數據庫打交道,在單元測試中直接使用數據庫又顯得太重,如果可以方便的編寫一些測試數據,這樣更易於檢測功能。如何模擬數據庫行為便是本篇的主題。微軟有教程說明Moq Entity Framework,需註意的是EF的版本必須是6以上。但在這篇教程中是直接使用DbContext,而自己的應用程序中都是用UnitOfWork模式。經過修改後也可以實現類似功能。
二、參考文獻
https://msdn.microsoft.com/en-us/data/dn314429
三、采用UnitOfWork模式管理數據庫
UnitOfWork
public interfaceIDomainUnitOfWork : IDisposable { DbContext Db { get; } //ImsDbContext dbContext { get; } Task SaveChangesClientWinAsync(); Task SaveChangesDataBaseWinAsync(); void SaveChangesClientWin(); void SaveChangesDataBaseWin(); }
Repository接口
publicinterface IDomainRepositoryAsync<T> where T : class { //Async Task<List<T>> GetAllAsync(Expression<Func<T, bool>> predicate = null); Task<T> SingleAsync(object primaryKey); Task<T> SingleOrDefaultAsync(object primaryKey); Task<bool> IsExistsAsync(Expression<Func<T, bool>> predicate = null); //同步 IQueryable<T> GetAll(Expression<Func<T, bool>> predicate = null); T Single(object primaryKey); T SingleOrDefault(object primaryKey); bool IsExist(Expression<Func<T, bool>> predicate = null); void Add(T entity); void Update(T entity); void Delete(T entity); }
Repository實現
public class DomainRepositoryAsync<T> : IDomainRepositoryAsync<T> where T : class { private readonly IDomainUnitOfWork _unitOfWork; internal DbSet<T> dbSet; public DomainRepositoryAsync(IDomainUnitOfWork unitOfWork) { if (unitOfWork == null) throw new ArgumentNullException("unitOfWork"); this._unitOfWork = unitOfWork; this.dbSet = _unitOfWork.Db.Set<T>(); } public void Add(T entity) { dynamic obj = dbSet.Add(entity); } public void Delete(T entity) { if (_unitOfWork.Db.Entry(entity).State == EntityState.Detached) { dbSet.Attach(entity); } dynamic obj = dbSet.Remove(entity); } public async Task<List<T>> GetAllAsync(Expression<Func<T, bool>> predicate = null) { if (predicate != null) { return await this.dbSet.Where(predicate).ToListAsync(); } return await this.dbSet.ToListAsync(); } public async Task<bool> IsExistsAsync(Expression<Func<T, bool>> predicate = null) { var result = false; if (predicate == null) { return result; } var query = await this.dbSet.Where(predicate).FirstOrDefaultAsync(); result = query == null ? false : true; return result; } /// <summary> /// 如果沒有找到指定鍵元素,拋出異常. /// </summary> /// <param name="primaryKey">The primary key.</param> /// <returns>Task<T>.</returns> /// <exception cref="System.Collections.Generic.KeyNotFoundException"></exception> public async Task<T> SingleAsync(object primaryKey) { T dbResult = null; dbResult = await dbSet.FindAsync(primaryKey); if (dbResult == null) { throw new KeyNotFoundException(); } return dbResult; } public async Task<T> SingleOrDefaultAsync(object primaryKey) { var dbResult = await dbSet.FindAsync(primaryKey); return dbResult; } public void Update(T entity) { this.dbSet.Attach(entity); _unitOfWork.Db.Entry(entity).State = EntityState.Modified; } public IQueryable<T> GetAll(Expression<Func<T, bool>> predicate = null) { if (predicate != null) { return this.dbSet.Where(predicate); } return this.dbSet; } public T Single(object primaryKey) { T dbResult = null; dbResult = dbSet.Find(primaryKey); if (dbResult == null) { throw new KeyNotFoundException(); } return dbResult; } public T SingleOrDefault(object primaryKey) { var dbResult = dbSet.Find(primaryKey); return dbResult; } public bool IsExist(Expression<Func<T, bool>> predicate = null) { var result = false; if (predicate == null) { return result; } var query = this.dbSet.Where(predicate).FirstOrDefault(); result = query == null ? false : true; return result; } }
DbContext
public class DurationDbContext : DbContext { public virtual DbSet<Department> Departments { get; set; } public virtual DbSet<Duration> Durations { get; set; } }
四、配置UnitTest
1、首先用Nuget安裝moq
2、註意在DomainRepositoryAsync中有一個DbSet<T> dbSet,需要Moq的就是該類型,並且在DbContext中的必須加"virtual“關鍵字。
3、Moq代碼
var unitOfWork = new Mock<IDomainUnitOfWork>(); var mockDepartment = SetupMockDbSet<Department>(DepartmentList); var mockDuration = SetupMockDbSet<Duration>(DurationList); unitOfWork.Setup(m => m.Db.Set<Department>()).Returns(mockDepartment.Object); unitOfWork.Setup(m => m.Db.Set<Duration>()).Returns(mockDuration.Object);
在教程中說到了如何處理異步的查詢操作,教程很詳細,此處便不再重復,直接將代碼Copy到單元測試工程中即可,再將重復的代碼作為一個方法SetupMockDBSet。
public static Mock<DbSet<T>> SetupMockDbSet<T>(List<T> dataList) where T : class { var data = dataList.AsQueryable(); var mockSet = new Mock<DbSet<T>>(); mockSet.As<IDbAsyncEnumerable<T>>() .Setup(m => m.GetAsyncEnumerator()) .Returns(new TestDbAsyncEnumerator<T>(data.GetEnumerator())); mockSet.As<IQueryable<T>>() .Setup(m => m.Provider) .Returns(new TestDbAsyncQueryProvider<T>(data.Provider)); mockSet.As<IQueryable<T>>().Setup(m => m.Expression).Returns(data.Expression); mockSet.As<IQueryable<T>>().Setup(m => m.ElementType).Returns(data.ElementType); mockSet.As<IQueryable<T>>().Setup(m => m.GetEnumerator()).Returns(data.GetEnumerator()); return mockSet; }
註意在配置UnitOfWork時,用Setup中是對IUnitOfWork的Db進行設置。接下來的實現方式與教程相同,不再重復。
利用Mocking Framework 單元測試Entity Framework