如何使用Moq對我的EF存盤庫方法進行單元測驗？

我正在嘗試為其使用 DbContext 和 Add 方法的 Create 方法為我的存盤庫類撰寫一個單元測驗。

我的想法是計算現有記錄的數量。呼叫創建方法。獲取新的記錄計數并檢查它是否增加了 1。

但是，在運行單元測驗時，呼叫 Add 方法時出錯，并出現以下錯誤：

{"Cannot access a disposed context instance. A common cause of this error is disposing a context instance that was resolved from dependency injection and then later trying to use the same context instance elsewhere in your application. This may occur if you are calling 'Dispose' on the context instance, or wrapping it in a using statement. If you are using dependency injection, you should let the dependency injection container take care of disposing context instances.\r\nObject name: 'DbContext'."}

我試圖理解為什么會這樣以及如何克服這個問題？

public class MyDatabaseContext : DbContext
{
    public MyDatabaseContext(DbContextOptions<MyDatabaseContext> options) : base(options)
    {
    }

    public DbSet<Record> Records { get; set; }

    protected override void OnModelCreating(ModelBuilder modelBuilder)
    {
        modelBuilder.Entity<Record>();
    }
}

public class Repository : IRepository
{
    private readonly MyDatabaseContext _dbContext;

    public Repository(MyDatabaseContext dbContext)
    {
        _dbContext = dbContext;
    }

    public Record Create(Record record)
    {
        try
        {
            using (_dbContext)
            {
                var response = _dbContext.Records.Add(record); //erroring line
                _dbContext.SaveChanges();
                return response.Entity;
            }
        }
        catch (Exception ex)
        {
            return null;
        }
    }
    
    public IEnumerable<Record> GetAll()
    {
        try
        {
            using (_dbContext)
            {
                return _dbContext.Records.ToList();
            }
        }
        catch (Exception ex)
        {
            return null;
        }
    }
}

public interface IRepository
{
    Record Create(Record record);
    IEnumerable<Record> GetAll();
}

啟動.cs：

services.AddDbContext<MyDatabaseContext>(opt => opt.UseInMemoryDatabase("memoryDb"));
services.AddScoped<IRepository, Repository>();

單元測驗：

[TestMethod]
public async Task Create_Successfully()
{
    var repository = new Repository(await GetDbContext());
    var existingRecords = repository.GetAll();

    repository.Create(new Record());
    var newRecords = repository.GetAll();

    Assert.AreEqual(3, existingRecords.Count());
    Assert.AreEqual(4, newRecords.Count());
}

private async Task<DbContext> GetDbContext()
{
    var options = new DbContextOptionsBuilder<DbContext>().UseInMemoryDatabase(Guid.NewGuid().ToString()).Options;

    var context = new DbContext(options);
    context.Database.EnsureCreated();

    if (await context.Records.CountAsync() <= 0)
    {
        for (int i = 1; i <= 3; i  )
        {
            context.Records.Add(new Records());
            await context.SaveChangesAsync();
        }
    }

    return context;
}

uj5u.com熱心網友回復：

您需要洗掉GetAllandCreate方法中的 using 陳述句：

public Record Create(Record record)
{
    try
    {
        using (_dbContext)
        {
            var response = _dbContext.Records.Add(record); //erroring line
            _dbContext.SaveChanges();
            return response.Entity;
        }
    }
    catch (Exception ex)
    {
        return null;
    }
}

至：

public Record Create(Record record)
{
    try
    {
        var response = _dbContext.Records.Add(record); //erroring line
        _dbContext.SaveChanges();
        return response.Entity;
    }
    catch (Exception ex)
    {
        return null;
    }
}

您無需擔心處置服務，因為容器會在生產環境中為您執行此操作。在你的測驗中，如果你想清理東西，你可以這樣做：

[TestMethod]
public async Task Create_Successfully()
{
    using (var context = await GetDbContext())
    {
        var repository = new Repository(context);
        var existingRecords = repository.GetAll();

        repository.Create(new Record());
        var newRecords = repository.GetAll();

        Assert.AreEqual(3, existingRecords.Count());
        Assert.AreEqual(4, newRecords.Count());
    }
}

標籤：C＃ 单元测试 实体框架核心 起订量

上一篇：如何在C#中評估兩個具有相同值而不相等的列舉成員？

下一篇：如何使用Blazor中另一個選擇框的選定項更改選擇框的串列元素？