[英]Moq - Mock DbSet<T>.AddAsync throws no invocations performed
我有一個單元測試,它基本上是在測試 EF Core 的行為。 我要測試的課程如下所示:
namespace MusicPortal.Repository.Repository
{
public class ArtistRepository : IArtistRepository
{
private readonly MusicPortalDbContext _context;
public ArtistRepository(MusicPortalDbContext context)
{
_context = context;
}
public async Task<MusicPortalDatabaseResponse<bool>> AddNewArtist(Artist artist)
{
try
{
await _context.Artists.AddAsync(new Artist
{
ArtistType = ArtistTypes.Band,
City = artist.City,
Country = artist.Country,
Genre = artist.Genre,
Name = artist.Name,
ProfileImageUrl = artist.ProfileImageUrl
});
_context.SaveChanges();
return new MusicPortalDatabaseResponse<bool>
{
HasError = false,
Exception = null,
Response = true
};
}
catch (Exception e)
{
return new MusicPortalDatabaseResponse<bool>
{
HasError = true,
Exception = e,
Response = false
};
}
}
}
}
我使用 Moq 進行了以下單元測試
namespace MusicPortal.Tests.Repository.ArtistRepository.AddNewArtist
{
[TestFixture]
public class GivenAddingANewArtistToADatabaseFails
{
private Mock<DbSet<Artist>> _mockArtistDbSet;
private Mock<MusicPortalDbContext> _mockContext;
private IArtistRepository _artistRepository;
private MusicPortalDatabaseResponse<bool> _addArtistToDbResponse;
[OneTimeSetUp]
public async Task Setup()
{
_mockArtistDbSet = new Mock<DbSet<Artist>>();
_mockContext = new Mock<MusicPortalDbContext>();
_mockArtistDbSet
.Setup(x => x.AddAsync(It.IsAny<Artist>(), It.IsAny<CancellationToken>()))
.Callback((Artist artist, CancellationToken token) => { })
.ReturnsAsync(It.IsAny<EntityEntry<Artist>>());
_mockContext
.Setup(x => x.SaveChanges())
.Throws(new Exception("Cannot save new Artist to Database"));
_artistRepository = new MusicPortal.Repository.Repository.ArtistRepository(_mockContext.Object);
_addArtistToDbResponse = await _artistRepository.AddNewArtist(It.IsAny<Artist>());
}
[Test]
public void ThenANegativeResultIsReturned() // pass
{
Assert.IsFalse(_addArtistToDbResponse.Response);
Assert.IsTrue(_addArtistToDbResponse.HasError);
Assert.IsInstanceOf<Exception>(_addArtistToDbResponse.Exception);
}
[Test]
public void ThenTheArtistContextAddMethodIsCalledOnce() //fail
{
_mockArtistDbSet.Verify(x => x.AddAsync(It.IsAny<Artist>(), It.IsAny<CancellationToken>()), Times.Once);
}
[Test]
public void ThenTheArtistsContextSaveMethodIsNeverCalled() //pass
{
_mockContext.Verify(x => x.SaveChanges(), Times.Never);
}
}
}
第一個和最后一個斷言通過但ThenTheArtistContextAddMethodIsCalledOnce()
由於以下錯誤而失敗:
MusicPortal.Tests.Repository.ArtistRepository.AddNewArtist.GivenAddingANewArtistToADatabaseFails.ThenTheArtistContextAddMethodIsCalledOnce
Moq.MockException :預期在模擬上調用一次,但為 0 次:x => x.AddAsync(It.IsAny(), It.IsAny())
執行的調用:
Mock:1> (x):未執行調用。
在 Moq.Mock.Verify(Mock mock, LambdaExpression expression, Times times, String failMessage) at Moq.Mock
1.Verify[TResult](Expression
1 expression, Func`1 times) at MusicPortal.Tests.Repository.ArtistRepository.AddNewArtist。 GivenAddingANewArtistToADatabaseFails.TheArtistContextAddMethodIsCalledOnce() in MusicPortal.Tests\\Repository\\ArtistRepository\\AddNewArtist\\GivenAddingANewArtistToADatabaseFails.cs:line 53
我明白問題代碼是c# _mockArtistDbSet .Setup(x => x.AddAsync(It.IsAny<Artist>(), It.IsAny<CancellationToken>())) .Callback((Artist artist, CancellationToken token) => { }) .ReturnsAsync(It.IsAny<EntityEntry<Artist>>());
而且我知道問題很可能是由於異步問題,但我不知道為什么,或者實際問題是什么。 任何建議,解決方案?
您聲明並設置 _mockArtistDbSet,但不使用/將其附加到 _mockContext。 我認為您需要添加以下內容:
_mockContext.Setup(m => m.Artist).Returns(_mockArtistDbSet.Object);
所以看起來 EF Core 不太容易用SaveChangesAsync
和AddAsync
等異步任務進行測試。 最后,我按照 MS 指南測試 EF 核心並創建了一個模擬上下文。 唯一的缺點是我只能測試快樂路徑。 雖然錯誤路徑是由使用存儲庫的服務測試的,但我希望在存儲庫層有更多的測試覆蓋。
無論如何,這是規格
using System.Linq;
using System.Threading.Tasks;
using Microsoft.EntityFrameworkCore;
using MusicPortal.Core.Context;
using MusicPortal.Core.Repository;
using MusicPortal.Tests.Repository.ArtistRepository.TestHelpers;
using MusicPortal.Tests.Repository.ArtistRepository.TestHelpers.MockDB;
using NUnit.Framework;
using MockArtistRepository = MusicPortal.Repository.Repository.ArtistRepository;
namespace MusicPortal.Tests.Repository.ArtistRepository.AddNewArtist
{
[TestFixture]
public class GivenANewArtistToInsertIntoTheDb
{
private DbContextOptions<MusicPortalDbContext> _options;
private MusicPortalDatabaseResponse<bool> _mockResponse;
[OneTimeSetUp]
public async Task Setup()
{
_options = new MockDbFactory("MusicPortalDB").Options;
using (var context = new MusicPortalDbContext(_options))
{
var artistRepository = new MockArtistRepository(context);
_mockResponse = await artistRepository.AddNewArtist(MockRepositoryData.Artist);
}
}
[Test]
public void AndThenAPositiveResultIsReturned()
{
Assert.Null(_mockResponse.Exception);
Assert.IsTrue(_mockResponse.Response);
Assert.IsFalse(_mockResponse.HasError);
}
[Test]
public void ThenTheArtistShouldBeSavedWithNoProblem()
{
using (var context = new MusicPortalDbContext(_options))
{
Assert.AreEqual(1, context.Artists.Count());
}
}
}
}
和模擬數據庫:
using System;
using Microsoft.EntityFrameworkCore;
using MusicPortal.Core.Context;
using MusicPortal.Core.DBModels;
namespace MusicPortal.Tests.Repository.ArtistRepository.TestHelpers.MockDB
{
public sealed class MockDbFactory
{
public DbContextOptions<MusicPortalDbContext> Options { get; }
public MockDbFactory(string dbName)
{
Options = new DbContextOptionsBuilder<MusicPortalDbContext>()
.UseInMemoryDatabase(dbName)
.Options;
}
public void AddArtistsToContext()
{
using (var context = new MusicPortalDbContext(Options))
{
context.Artists.Add(new Artist
{
City = "Orange County",
Country = "USA",
Events = null,
Genre = "Pop Punk",
Id = Guid.Parse("8a07504b-8152-4d8b-8e21-74bf64322ebc"),
Merchandise = null,
Name = "A Day To Remember",
ArtistType = "Band",
ProfileImageUrl = "https://placehold.it/30x30"
});
context.SaveChanges();
}
}
}
}
我希望這可以幫助任何人看到相同的問題。 學到的教訓是不要使用異步,除非你絕對必須。
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