Question

运行测试时，我一直收到空引用错误，但无法弄清楚。以下是我的测试

[Test]
[TestCase(...)]
public void Get_ShouldReturnTradesMock(string field, Operator op, int dayManip, SortDirection sortDir, string filterTerm, int pageIndex, int pageSize, int expectedRecordMinSize)
{
    using (var _imprintDbContext = new ImprintDbContext(_dbContextOptions))
    {
        var mockExecRepo = new Mock<IExecutionReportRepository>();
        mockExecRepo.Setup(mock => mock.GetFilteredTrades(It.IsAny<IEnumerable<Query>>(), It.IsAny<int>(), It.IsAny<int>(), It.IsAny<string>())).Verifiable();//.Returns<Task<PagedResult<ExecutionReport>>>(x => null);

        var uow = new Mock<IUnitOfWork>();
        uow.SetupGet(x => x.ExecutionReports).Returns(mockExecRepo.Object);

        var controller = new TradesController(uow.Object);

        var query = new Query()
        {
            Field = field,
            Operator = op,
            Search = DateTime.Now.Add(TimeSpan.FromDays(dayManip)).Date.ToString("yyyy-MM-dd"),
            SortDirection = sortDir
        };

        TradesController.TradesBody tb = new TradesController.TradesBody()
        {
            queries = new[] { query },
            filterTerm = filterTerm
        };

        var results = controller.Get(tb, pageIndex, pageSize);

        uow.Verify(mock => mock.ExecutionReports.GetFilteredTrades(new[] { query }, pageIndex, pageSize, filterTerm), Times.Once());
    }
}

以及我在嘲笑的一些对象的定义：

public interface IExecutionReportRepository : IRepository<ExecutionReport>
{
    ...
    Task<IPagedResult<ExecutionReport>> GetFilteredTrades(IEnumerable<Query> queries, int pageIndex, int pageSize, string filterTerm);

}

UnitOfWork：

public class UnitOfWork : IUnitOfWork
{
    private readonly DbContext _context;

    public UnitOfWork(DbContext context, IExecutionReportRepository executionReportRepository)
    {
        _context = context;
        ExecutionReports = executionReportRepository;
    }

    public IExecutionReportRepository ExecutionReports { get; }
}

TradesController：

public class TradesController : Controller
{
    public class TradesBody
    {
        public IEnumerable<Query> queries;
        public string filterTerm;
    }

    private readonly IUnitOfWork unitOfWork;

    public TradesController(IUnitOfWork unitOfWork)
    {
        this.unitOfWork = unitOfWork;
    }

    /// <summary>
    /// Gets a list of trades for the current date
    /// </summary>
    [HttpPost]
    public async Task<IActionResult> Get([FromBody] TradesBody postBody, int pageIndex = 0, int pageSize = 100)
    {
            string filterTerm = postBody.filterTerm ?? "";
            IEnumerable<Query> queries = postBody.queries;
            IPagedResult<Domain.Entities.Core.ExecutionReport> queryResult;
            queryResult = await unitOfWork.ExecutionReports.GetFilteredTrades(queries, pageIndex, pageSize, filterTerm); //Null reference error here
            return Ok(queryResult);
    }
}

单步执行代码时，我看不到任何空对象，因此实际上看不到/无法理解在哪里找到了空引用，但是我注意到，在调试期间，我无法看到'{{ 1}}。从this来看，我的模拟方法未连接到正在执行的方法，但是我只有一个GetFilteredTrades。

如何解决在GetFilteredTrades中引发的空引用错误并成功运行测试？

Answer 1

您没有设置GetFilteredTrades来返回任何内容，因此在尝试等待时失败。

mockExecRepo
    .Setup(mock => mock.GetFilteredTrades(It.IsAny<IEnumerable<Query>>(), It.IsAny<int>(), It.IsAny<int>(), It.IsAny<string>()))
    .ReturnAsync(Mock.Of<IPagedResult<ExecutionReport>>()) //<--THIS
    .Verifiable();

同样，被测方法是异步的，因此测试也应该是异步的。

[Test]
[TestCase(...)]
public async Task Get_ShouldReturnTradesMock(string field, Operator op, int dayManip, SortDirection sortDir, string filterTerm, int pageIndex, int pageSize, int expectedRecordMinSize)
{

和待测方法正在等待

var results = await controller.Get(tb, pageIndex, pageSize);

最后，您正在根据设置验证错误的模拟。由于mockExecRepo设置具有Verifiable()，因此您可以简单地在模拟中调用Verify()。

//...

//Act
var results = await controller.Get(tb, pageIndex, pageSize);

//Assert
mockExecRepo.Verify();

验证它是否按预期被调用。

使用NUnit和Moq进行测试时出现意外的空引用

1 个答案: