如何对时间触发的 azure function 进行单元测试？ 我的测试不起作用

Question

At first, code from my test:

using Microsoft.AspNetCore.Http;
using Moq;
using NUnit.Framework;
using System.IO;
using System.Threading.Tasks;
using TeamsAllocationManager.Api.Functions;
using TeamsAllocationManager.Contracts.Base;
using TeamsAllocationManager.Contracts.EmployeeWorkingTypeHistory;
using Microsoft.Extensions.Logging;
using System.Linq.Expressions;
using System;

namespace TeamsAllocationManager.Tests.Functions
{
    [TestFixture]
    public class HistoryClearingFunctionTests
    {
        private readonly ILogger _mockedLogger;
        private readonly Mock<IDispatcher> _dispatcherMock;

        public HistoryClearingFunctionTests()
        {
            _mockedLogger = new Mock<ILogger>().Object;
            _dispatcherMock = new Mock<IDispatcher>();
        }

        [Test]
        public async Task ShouldCallClearOldEmployeeWorkingTypeHistoryRecordsCommand() =>
            await VerifyFunctionExecutionAsync(c => c.DispatchAsync<ClearOldEmployeeWorkingTypeHistoryRecordsCommand, bool>(It.IsAny<ClearOldEmployeeWorkingTypeHistoryRecordsCommand>(), default), "GET");
        private async Task VerifyFunctionExecutionAsync(Expression<Action<IDispatcher>> expression, string verb, string path = "", QueryCollection? query = null, MemoryStream? body = null)
        {
            // given
            var function = new HistoryClearingFunction(_dispatcherMock.Object);
            var reqMock = new Mock<HttpRequest>();
            reqMock.Setup(r => r.Method).Returns(verb);
            reqMock.Setup(r => r.Query).Returns(query ?? new QueryCollection());
            reqMock.Setup(r => r.Body).Returns(body ?? new MemoryStream());

            // when
            await function.RunAsync(reqMock.Object, path, _mockedLogger);

            // then
            _dispatcherMock.Verify(expression, Times.Once);
        }
    }
}

Currently i have one error at line 29, where i have await VerifyFunctionExecutionAsync. The error was on DispatchAsync<Clear***Command> and it sounds like this:

'TeamsAllocationManager.Contracts.EmployeeWorkingTypeHistory.ClearOldEmployeeWorkingTypeHistoryRecordsCommand' cannot be used as type parameter 'TCommand' in the generic type or method 'ICommandDispatcher.DispatchAsync(TCommand, CancellationToken)'. There is no implicit reference conversion from 'TeamsAllocationManager.Contracts.EmployeeWorkingTypeHistory.ClearOldEmployeeWorkingTypeHistoryRecordsCommand' to 'TeamsAllocationManager.Contracts.Base.Commands.ICommand'. TeamsAllocationManager.Tests

Im newbie in azure functions and don't know how to fix it. The rest of code (tested function) works fine, so there is only issue with test.

#Update 1 Fixed bugs in code above and add the function code below:

using Microsoft.Azure.WebJobs;
using System.Threading.Tasks;
using TeamsAllocationManager.Contracts.Base;
using TeamsAllocationManager.Contracts.EmployeeDeskHistory;
using TeamsAllocationManager.Contracts.EmployeeWorkingTypeHistory;

namespace TeamsAllocationManager.Api.Functions
{
    public class HistoryClearingFunction : FunctionBase
    {
        private readonly IDispatcher _dispatcher;
        public HistoryClearingFunction(IDispatcher dispatcher)
        {
            _dispatcher = dispatcher;
        }
        [FunctionName("EmployeeWorkingTypeHistoryClearingFunction")]
        public async Task EmployeeWorkingTypeHistoryClearingFunction([TimerTrigger("0 0 0 1 * *")]TimerInfo myTimer) 
        {
            await _dispatcher.DispatchAsync<ClearOldEmployeeWorkingTypeHistoryRecordsCommand, bool>(new ClearOldEmployeeWorkingTypeHistoryRecordsCommand());
        }
        [FunctionName("EmployeeDeskHistoryClearingFunction")]
        public async Task EmployeeDeskHistoryClearingFunction([TimerTrigger("0 0 0 1 * *")] TimerInfo myTimer)
        {
            await _dispatcher.DispatchAsync<ClearOldEmployeeDeskHistoryRecordsCommand, bool>(new ClearOldEmployeeDeskHistoryRecordsCommand());
        }
    }
}

Current error:

Message: Moq.MockException: Expected invocation on the mock once, but was 0 times: c => c.DispatchAsync<ClearOldEmployeeWorkingTypeHistoryRecordsCommand, bool>(It.IsAny(), CancellationToken)

Performed invocations:

MockIDispatcher:1 (c):

No invocations performed.

Answer 1

I would recommend to solve this by a architectural change.

Move all functional code that is not direct related to the function Technologie itself into a helper class. Then write the UnitTest against this helper class.

This will make it much easier to test the code that is doing the productive work.