如何验证返回列表函数 C# 的断言抛出异常

Question

How do I use Assert (or other Test class) to verify that an exception has been thrown?

public async Task<IEnumerable<HHABranchAggregatorConfigurationDto>> HHABranchAggregatorDetails(int HHA, int UserId, int HHA_Branch_ID)
{
    IEnumerable<HHABranchAggregatorConfigurationDto> hhabranchAggregatorsettingslists = new List<HHABranchAggregatorConfigurationDto>();

    try
    {
        var EVVVendorMasterList = await _UAEVVVendorMasterRepository._HHA_Schedule_GetUAEVVVendorMaster(HHA, UserId, "EvvVendorMasterID,VendorName,isPrimary");
    }
    catch (Exception e)
    {
        _logger.LogError(e.Message);
    }

    return hhabranchAggregatorsettingslists;
}

Unit Test In this unit test trying to capture the null reference exception

[Fact]
public async Task Agency_Configuration_Should_Throw_Exception()
{
    //Arrange
    _UAEVVVendorMasterRepositoryMock.Setup(x => x._HHA_Schedule_GetUAEVVVendorMaster(It.IsAny<int>(), It.IsAny<int>(), It.IsAny<string>())).Throws<NullReferenceException>();
    //Act
    var hhabranchAggregatorsactuallist = await agencyConfigurations.HHABranchAggregatorDetails(1, 1, 3052);
    //Assert
    var ex = Assert.Throws<Exception>(() => hhabranchAggregatorsactuallist);
}

But while doing this getting this error message needs suggestion

Assert.Throws() Failure
Expected: typeof(System.Exception)
Actual: (No exception was thrown)

Answer 1

使用ThrowsAsync而不是Throws ：

var ex = await Assert.ThrowsAsync<Exception>(async () => await agencyConfigurations.HHABranchAggregatorDetails(1, 1, 3052));

Answer 2

I assume because you catch the exception in the target method named " HHABranchAggregatorDetails ", the Assert API doesn't notice it. You would need to either not catch or to rethrow it, I guess.

But of course its better in productive code to catch it ^^