[英]How to mock an async repository with Entity Framework Core
我正在尝试为调用异步存储库的 class 创建一个单元测试。 我正在使用 ASP.NET 核心和实体框架核心。 我的通用存储库看起来像这样。
public class EntityRepository<TEntity> : IEntityRepository<TEntity> where TEntity : class
{
private readonly SaasDispatcherDbContext _dbContext;
private readonly DbSet<TEntity> _dbSet;
public EntityRepository(SaasDispatcherDbContext dbContext)
{
_dbContext = dbContext;
_dbSet = dbContext.Set<TEntity>();
}
public virtual IQueryable<TEntity> GetAll()
{
return _dbSet;
}
public virtual async Task<TEntity> FindByIdAsync(int id)
{
return await _dbSet.FindAsync(id);
}
public virtual IQueryable<TEntity> FindBy(Expression<Func<TEntity, bool>> predicate)
{
return _dbSet.Where(predicate);
}
public virtual void Add(TEntity entity)
{
_dbSet.Add(entity);
}
public virtual void Delete(TEntity entity)
{
_dbSet.Remove(entity);
}
public virtual void Update(TEntity entity)
{
_dbContext.Entry(entity).State = EntityState.Modified;
}
public virtual async Task SaveChangesAsync()
{
await _dbContext.SaveChangesAsync();
}
}
然后我有一个服务 class 在存储库的实例上调用 FindBy 和 FirstOrDefaultAsync:
public async Task<Uri> GetCompanyProductURLAsync(Guid externalCompanyID, string productCode, Guid loginToken)
{
CompanyProductUrl companyProductUrl = await _Repository.FindBy(u => u.Company.ExternalCompanyID == externalCompanyID && u.Product.Code == productCode.Trim()).FirstOrDefaultAsync();
if (companyProductUrl == null)
{
return null;
}
var builder = new UriBuilder(companyProductUrl.Url);
builder.Query = $"-s{loginToken.ToString()}";
return builder.Uri;
}
我正在尝试在下面的测试中模拟存储库调用:
[Fact]
public async Task GetCompanyProductURLAsync_ReturnsNullForInvalidCompanyProduct()
{
var companyProducts = Enumerable.Empty<CompanyProductUrl>().AsQueryable();
var mockRepository = new Mock<IEntityRepository<CompanyProductUrl>>();
mockRepository.Setup(r => r.FindBy(It.IsAny<Expression<Func<CompanyProductUrl, bool>>>())).Returns(companyProducts);
var service = new CompanyProductService(mockRepository.Object);
var result = await service.GetCompanyProductURLAsync(Guid.NewGuid(), "wot", Guid.NewGuid());
Assert.Null(result);
}
但是,当测试执行对存储库的调用时,我收到以下错误:
The provider for the source IQueryable doesn't implement IAsyncQueryProvider. Only providers that implement IEntityQueryProvider can be used for Entity Framework asynchronous operations.
如何正确模拟存储库以使其正常工作?
感谢@Nkosi 将我指向一个链接,其中包含在 EF 6 中执行相同操作的示例: https ://msdn.microsoft.com/en-us/library/dn314429.aspx。 这与 EF Core 并不完全一样,但我能够从它开始并进行修改以使其正常工作。 下面是我创建的用于“模拟”IAsyncQueryProvider 的测试类:
internal class TestAsyncQueryProvider<TEntity> : IAsyncQueryProvider
{
private readonly IQueryProvider _inner;
internal TestAsyncQueryProvider(IQueryProvider inner)
{
_inner = inner;
}
public IQueryable CreateQuery(Expression expression)
{
return new TestAsyncEnumerable<TEntity>(expression);
}
public IQueryable<TElement> CreateQuery<TElement>(Expression expression)
{
return new TestAsyncEnumerable<TElement>(expression);
}
public object Execute(Expression expression)
{
return _inner.Execute(expression);
}
public TResult Execute<TResult>(Expression expression)
{
return _inner.Execute<TResult>(expression);
}
public IAsyncEnumerable<TResult> ExecuteAsync<TResult>(Expression expression)
{
return new TestAsyncEnumerable<TResult>(expression);
}
public Task<TResult> ExecuteAsync<TResult>(Expression expression, CancellationToken cancellationToken)
{
return Task.FromResult(Execute<TResult>(expression));
}
}
internal class TestAsyncEnumerable<T> : EnumerableQuery<T>, IAsyncEnumerable<T>, IQueryable<T>
{
public TestAsyncEnumerable(IEnumerable<T> enumerable)
: base(enumerable)
{ }
public TestAsyncEnumerable(Expression expression)
: base(expression)
{ }
public IAsyncEnumerator<T> GetEnumerator()
{
return new TestAsyncEnumerator<T>(this.AsEnumerable().GetEnumerator());
}
IQueryProvider IQueryable.Provider
{
get { return new TestAsyncQueryProvider<T>(this); }
}
}
internal class TestAsyncEnumerator<T> : IAsyncEnumerator<T>
{
private readonly IEnumerator<T> _inner;
public TestAsyncEnumerator(IEnumerator<T> inner)
{
_inner = inner;
}
public void Dispose()
{
_inner.Dispose();
}
public T Current
{
get
{
return _inner.Current;
}
}
public Task<bool> MoveNext(CancellationToken cancellationToken)
{
return Task.FromResult(_inner.MoveNext());
}
}
这是我使用这些类的更新测试用例:
[Fact]
public async Task GetCompanyProductURLAsync_ReturnsNullForInvalidCompanyProduct()
{
var companyProducts = Enumerable.Empty<CompanyProductUrl>().AsQueryable();
var mockSet = new Mock<DbSet<CompanyProductUrl>>();
mockSet.As<IAsyncEnumerable<CompanyProductUrl>>()
.Setup(m => m.GetEnumerator())
.Returns(new TestAsyncEnumerator<CompanyProductUrl>(companyProducts.GetEnumerator()));
mockSet.As<IQueryable<CompanyProductUrl>>()
.Setup(m => m.Provider)
.Returns(new TestAsyncQueryProvider<CompanyProductUrl>(companyProducts.Provider));
mockSet.As<IQueryable<CompanyProductUrl>>().Setup(m => m.Expression).Returns(companyProducts.Expression);
mockSet.As<IQueryable<CompanyProductUrl>>().Setup(m => m.ElementType).Returns(companyProducts.ElementType);
mockSet.As<IQueryable<CompanyProductUrl>>().Setup(m => m.GetEnumerator()).Returns(() => companyProducts.GetEnumerator());
var contextOptions = new DbContextOptions<SaasDispatcherDbContext>();
var mockContext = new Mock<SaasDispatcherDbContext>(contextOptions);
mockContext.Setup(c => c.Set<CompanyProductUrl>()).Returns(mockSet.Object);
var entityRepository = new EntityRepository<CompanyProductUrl>(mockContext.Object);
var service = new CompanyProductService(entityRepository);
var result = await service.GetCompanyProductURLAsync(Guid.NewGuid(), "wot", Guid.NewGuid());
Assert.Null(result);
}
尝试使用我的 Moq/NSubstitute/FakeItEasy 扩展MockQueryable :支持所有同步/异步操作(请参阅此处的更多示例)
//1 - create a List<T> with test items
var users = new List<UserEntity>()
{
new UserEntity,
...
};
//2 - build mock by extension
var mock = users.AsQueryable().BuildMock();
//3 - setup the mock as Queryable for Moq
_userRepository.Setup(x => x.GetQueryable()).Returns(mock.Object);
//3 - setup the mock as Queryable for NSubstitute
_userRepository.GetQueryable().Returns(mock);
还支持 DbSet
//2 - build mock by extension
var mock = users.AsQueryable().BuildMockDbSet();
//3 - setup DbSet for Moq
var userRepository = new TestDbSetRepository(mock.Object);
//3 - setup DbSet for NSubstitute
var userRepository = new TestDbSetRepository(mock);
笔记:
少得多的代码解决方案。 使用内存数据库上下文,它应该负责为您引导所有集合。 您不再需要在您的上下文中模拟 DbSet,但是例如,如果您想从服务返回数据,您可以简单地返回内存中上下文的实际设置数据。
DbContextOptions< SaasDispatcherDbContext > options = new DbContextOptionsBuilder< SaasDispatcherDbContext >()
.UseInMemoryDatabase(Guid.NewGuid().ToString())
.Options;
_db = new SaasDispatcherDbContext(optionsBuilder: options);
我正在维护两个开源项目,它们负责设置模拟并实际模拟SaveChanges(Async)
。
对于 EF Core: https : //github.com/huysentruitw/entity-framework-core-mock
对于 EF6: https : //github.com/huysentruitw/entity-framework-mock
这两个项目都有与 Moq 或 NSubstitute 集成的 Nuget 包。
这是 F# 的已接受答案的一个端口,我只是为自己做的,并认为它可以节省某人的时间。 我还更新了示例以匹配更新的 C#8 IAsyncEnumarable API,并将 Mock 设置调整为通用。
type TestAsyncEnumerator<'T> (inner : IEnumerator<'T> ) =
let inner : IEnumerator<'T> = inner
interface IAsyncEnumerator<'T> with
member this.Current with get() = inner.Current
member this.MoveNextAsync () = ValueTask<bool>(Task.FromResult(inner.MoveNext()))
member this.DisposeAsync () = ValueTask(Task.FromResult(inner.Dispose))
type TestAsyncEnumerable<'T> =
inherit EnumerableQuery<'T>
new (enumerable : IEnumerable<'T>) =
{ inherit EnumerableQuery<'T> (enumerable) }
new (expression : Expression) =
{ inherit EnumerableQuery<'T> (expression) }
interface IAsyncEnumerable<'T> with
member this.GetAsyncEnumerator cancellationToken : IAsyncEnumerator<'T> =
new TestAsyncEnumerator<'T>(this.AsEnumerable().GetEnumerator())
:> IAsyncEnumerator<'T>
interface IQueryable<'T> with
member this.Provider with get() = new TestAsyncQueryProvider<'T>(this) :> IQueryProvider
and
TestAsyncQueryProvider<'TEntity>
(inner : IQueryProvider) =
let inner : IQueryProvider = inner
interface IAsyncQueryProvider with
member this.Execute (expression : Expression) =
inner.Execute expression
member this.Execute<'TResult> (expression : Expression) =
inner.Execute<'TResult> expression
member this.ExecuteAsync<'TResult> ((expression : Expression), cancellationToken) =
inner.Execute<'TResult> expression
member this.CreateQuery (expression : Expression) =
new TestAsyncEnumerable<'TEntity>(expression) :> IQueryable
member this.CreateQuery<'TElement> (expression : Expression) =
new TestAsyncEnumerable<'TElement>(expression) :> IQueryable<'TElement>
let getQueryableMockDbSet<'T when 'T : not struct>
(sourceList : 'T seq) : Mock<DbSet<'T>> =
let queryable = sourceList.AsQueryable();
let dbSet = new Mock<DbSet<'T>>()
dbSet.As<IAsyncEnumerable<'T>>()
.Setup(fun m -> m.GetAsyncEnumerator())
.Returns(TestAsyncEnumerator<'T>(queryable.GetEnumerator())) |> ignore
dbSet.As<IQueryable<'T>>()
.SetupGet(fun m -> m.Provider)
.Returns(TestAsyncQueryProvider<'T>(queryable.Provider)) |> ignore
dbSet.As<IQueryable<'T>>().Setup(fun m -> m.Expression).Returns(queryable.Expression) |> ignore
dbSet.As<IQueryable<'T>>().Setup(fun m -> m.ElementType).Returns(queryable.ElementType) |> ignore
dbSet.As<IQueryable<'T>>().Setup(fun m -> m.GetEnumerator ()).Returns(queryable.GetEnumerator ()) |> ignore
dbSet
一种更简单的方法是在核心层之一中编写自己的ToListAsync
。 您不需要任何具体的类实现。 就像是:
public static async Task<List<T>> ToListAsync<T>(this IQueryable<T> queryable)
{
if (queryable is EnumerableQuery)
{
return queryable.ToList();
}
return await QueryableExtensions.ToListAsync(queryable);
}
这还有一个额外的好处,即您可以从应用程序的任何位置使用 ToListAsync,而无需一直拖动 EF 引用。
利用@Jed Veatch 接受的答案以及@Mandelbrotter 提供的评论,以下解决方案适用于 .NET Core 3.1 和 .NET 5。这将解决因使用上述内容而产生的“参数表达式无效”异常.NET 版本中的代码。
TL;DR - 完整的 EnumerableExtensions.cs 代码在这里。
用法:
public static DbSet<T> GetQueryableAsyncMockDbSet<T>(List<T> sourceList) where T : class
{
var mockAsyncDbSet = sourceList.ToAsyncDbSetMock<T>();
var queryable = sourceList.AsQueryable();
mockAsyncDbSet.As<IQueryable<T>>().Setup(m => m.GetEnumerator()).Returns(() => queryable.GetEnumerator());
mockAsyncDbSet.Setup(d => d.Add(It.IsAny<T>())).Callback<T>((s) => sourceList.Add(s));
return mockAsyncDbSet.Object;
}
然后,使用Moq和Autofixture ,您可以执行以下操作:
var myMockData = Fixture.CreateMany<MyMockEntity>();
MyDatabaseContext.SetupGet(x => x.MyDBSet).Returns(GetQueryableAsyncMockDbSet(myMockData));
对于所有在 mocking DbContext
中使用异步查询、 IAsyncQueryProvider
和其他内容的人。 下面是 netcore3.1 及更高版本的复制粘贴类型的示例用法。 基于通用 DbContextCreation 和通用 DbSet 种子。
public class MyDbContext : DbContext
{
public DbSet<MyEntity> MyEntities { get; set; }
}
public class MyEntity
{
public Guid Id { get; set; }
}
internal class MockDbContextAsynced<TDbContext>
{
private readonly TDbContext _mock;
public TDbContext Object => _mock;
public MockDbContextAsynced()
{
_mock = Activator.CreateInstance<TDbContext>();
}
// suppressed. see full code in source below
}
[Fact]
public void Test()
{
var testData = new List<MyEntity>
{
new MyEntity() { Id = Guid.NewGuid() },
new MyEntity() { Id = Guid.NewGuid() },
new MyEntity() { Id = Guid.NewGuid() },
};
var mockDbContext = new MockDbContextAsynced<MyDbContext>();
mockDbContext.AddDbSetData<MyEntity>(testData.AsQueryable());
mockDbContext.MyEntities.ToArrayAsync();
// or
mockDbContext.MyEntities.SingleAsync();
// or etc.
// To inject MyDbContext as type parameter with mocked data
var mockService = new SomeService(mockDbContext.Object);
}
有关完整实现的类型,请参阅此来源: https://gist.github.com/Zefirrat/a04658c827ba3ebffe03fda48d53ea11
我知道这个问题很老,但我找到了 nuget package 来做到这一点。
MockQueryable和MockQueryable.Moq
这为您完成了所有工作。
[TestCase("AnyFirstName", "AnyExistLastName", "01/20/2012", "Users with DateOfBirth more than limit")]
[TestCase("ExistFirstName", "AnyExistLastName", "02/20/2012", "User with FirstName already exist")]
[TestCase("AnyFirstName", "ExistLastName", "01/20/2012", "User already exist")]
public void CreateUserIfNotExist(string firstName, string lastName, DateTime dateOfBirth, string expectedError)
{
//arrange
var userRepository = new Mock<IUserRepository>();
var service = new MyService(userRepository.Object);
var users = new List<UserEntity>
{
new UserEntity {LastName = "ExistLastName", DateOfBirth = DateTime.Parse("01/20/2012", UsCultureInfo.DateTimeFormat)},
new UserEntity {FirstName = "ExistFirstName"},
new UserEntity {DateOfBirth = DateTime.Parse("01/20/2012", UsCultureInfo.DateTimeFormat)},
new UserEntity {DateOfBirth = DateTime.Parse("01/20/2012", UsCultureInfo.DateTimeFormat)},
new UserEntity {DateOfBirth = DateTime.Parse("01/20/2012", UsCultureInfo.DateTimeFormat)}
};
//expect
var mock = users.BuildMock();
userRepository.Setup(x => x.GetQueryable()).Returns(mock);
//act
var ex = Assert.ThrowsAsync<ApplicationException>(() =>
service.CreateUserIfNotExist(firstName, lastName, dateOfBirth));
//assert
Assert.AreEqual(expectedError, ex.Message);
}
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