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单元测试通用方法(NUnit)

nunit generics unit-testing c#

Ben_jamin · 技术社区 · 8 年前

我一直在尝试使用泛型类在.NETCore中实现存储库模式。这就是我想到的(我拿出了所有的方法,但只有一个保持简单)。类/方法可以工作,但我正在尝试为它编写一个单元(集成)测试,在本例中是Add方法。

public class Repository<TEntity> : IRepository<TEntity> where TEntity : class
{
    protected readonly DbContext Context;

    public Repository(DbContext context)
    {
        Context = context;
    }

     public void Add(TEntity entity)
    {
        Context.Set<TEntity>().Add(entity);
    }
}

到目前为止,我的集成测试如下:, 设置生成要保存到的SqlLite数据库

然后我创建一个“StorageSystem”域对象并测试泛型类。但我觉得我应该能够测试它,而不需要通过一个特定的领域模型。或者至少,输入不同的域模型作为参数化测试。

[TestFixture]
public class RepositoryTests
{
    SqliteConnection _connection;
    DbContextOptions<ApplicationDbContext> _options;
    ApplicationDbContext _context;
    UnitOfWork _uow;

    [SetUp]
    public void SetUp()
    {
        _connection = new SqliteConnection("DataSource=:memory:");
        _connection.Open();

        _options = new DbContextOptionsBuilder<ApplicationDbContext>()
            .UseSqlite(_connection)
            .Options;

        using (var context = new ApplicationDbContext(_options))
        {
            context.Database.EnsureCreated();
        }

        _context = new ApplicationDbContext(_options);
        _uow = new UnitOfWork(_context);
    }

    [TearDown]
    public void TearDown()
    {
        _connection.Close();
    }

    [Test]
    public void Add_AddsEntityToRepository()
    {
        //arrange
        var storageSystem = new StorageSystem {Id = 1, Name = "Storage1"};
        var repo = new Repository<StorageSystem>(_context);

        //act
        repo.Add(storageSystem);
        _uow.Complete();

        //assert
        Assert.AreEqual(1, _context.StorageSystems.Count());
    }

我对使用泛型相当陌生,我能找到的最接近的解决方案是使用抽象类。但是,我不能让它与我的代码一起工作,因为它不能将测试检测为抽象类,也不能生成TEntity类型的存储库。

Example taken from here

[TestFixture]
public abstract class RepositoryTests1<TEntity>
{
    SqliteConnection _connection;
    DbContextOptions<ApplicationDbContext> _options;
    ApplicationDbContext _context;
    UnitOfWork _uow;

    [SetUp]
    public void SetUp()
    {
        _connection = new SqliteConnection("DataSource=:memory:");
        _connection.Open();

        _options = new DbContextOptionsBuilder<ApplicationDbContext>()
            .UseSqlite(_connection)
            .Options;

        using (var context = new ApplicationDbContext(_options))
        {
            context.Database.EnsureCreated();
        }

        _context = new ApplicationDbContext(_options);

        _uow = new UnitOfWork(_context);
    }

    [TearDown]
    public void TearDown()
    {
        _connection.Close();
    }

[Test]
public void Add_AddsEntityToRepository_GenericAttempt()
    {
        //arrange
        TEntity entityToAdd = this.CreateEntity();

        var repo = new Repository<TEntity>(_context); //ERROR HERE - TEntity must be a reference type

        //act
        repo.Add(entityToAdd);
        _uow.Complete();

        //assert
        //NO IDEA WHAT THE ASSERTION WOULD BE
    }

    protected abstract TEntity CreateEntity();
}

简而言之,如何对这个通用存储库进行单元测试?

1 回复 | 直到 8 年前

Manuel Fuchs 8 年前

您可以将存储库限制为由您创建的某个基类,比如EntityBase(这应该是抽象的)

public class EntityBase
{
    public int Id { get; set;Â }
}

public class Repository<TEntity> : IRepository<TEntity> where TEntity : EntityBase
{
    ...
}

[Test]
public void Add_AddsEntityToRepository()
{
    //arrange
    var storageSystem = new StorageSystem {Id = 1, Name = "Storage1"};
    var repo = new Repository<EntityBase>(_context);

    //act
    repo.Add(storageSystem);
    _uow.Complete();

    //assert
    Assert.AreEqual(1, _context.StorageSystems.Count());
}

由于您要通过inherinition确保每个类型至少都有EntityBase的成员,因此不必进一步测试实体类型的继承树(除非您对此有特定的用例)

如果您需要知道基类上的某些方法,但实现依赖于子类,只需将该方法作为基类中的抽象成员并在子类中重写即可。

public class EntityBase
{
    public int Id { get; set; }

    // sample method that copies member values from other object to current instance
    public abstract void CopyProperties(EntityBase other);
}

public class Student : EntityBase
{
   public int Id { get; set; }

   public override void CopyProperties(EntityBase other)
   {
      ...
   }
}