如何触发 DataReceivedEventHandler？

Question

5-cent Version: How do you manually trigger a DataReceivedEventHandler? I recall using asynchronous delayed delegates to trip it, but I cannot figure out how.

5-dollar Version: I am currently doing Unit Testing on a project of mine, and I am currently trying to simulate a successful communication event. The method under test is as follows.

   public async Task<CommandResponse> StartScanAsync()
        {
            if (_isCommandInProgress)
            {
                Trace.WriteLine("Command in progress.");
                return new CommandResponse(CommandStatus.CommandInProgress);
            }
            else
            {
                Task<DongleResponse> t = WaitForDongleResponse(CommandId.CMD_START);
                byte[] sendBuf = { 0x00 };
                _serialDriver.send(sendBuf, 1);
                Trace.WriteLine("Command send. Waiting for response");

                // Wait for either dongle response or timeout
                // If dongleResponse comes first, set 
                if (await Task.WhenAny(t, Task.Delay(RECEIVE_TIMEOUT)) == t) {
                    _isScanning = true;
                    _isCommandInProgress = false;
                    return new CommandResponse(CommandStatus.OK, t.Result);
                }
                else
                {
                    _isCommandInProgress = false;
                    _rspRxTcs.SetCanceled();
                    return new CommandResponse(CommandStatus.ResponseTimeout);
                }
            }
        }

and below is my unit test code

using Microsoft.VisualStudio.TestTools.UnitTesting;
using Moq;
using FluentAssertions;
using System.Threading.Tasks;

namespace TriggerDataHandler.Tests
{// SUCCESSFULLY TRIGGER TIMEOUT AND SUCCESS PROMPTS
    [TestClass()]
    public class CommandServiceTestClass
    {
        private readonly Mock<ISerialDriver> MockDriver
            = new Mock<ISerialDriver>();

        [TestMethod()]
        public async Task StartScan_And_ReturnSUCCESS()
        //How to trigger dataHandler? return 0x0000
        {
            //Arrange: Set up variables for Act to work
            CommandService csGO = new CommandService(MockDriver.Object);

            //Act: Initiate StartScan and wait for a timeout to occur
            
            CommandResponse result = await csGO.StartScanAsync();

            //Assert: Your end goal which should be true
            Assert.AreEqual(result.Status, CommandStatus.OK);
        }
    }
}

I ain't allowed to put out anymore code at the moment, so if the information provided is insufficient, please provide me instead with some links you feel are relevant to the situation, and I'll try working my way up from there instead.

Thanks for reading btw.

Answer 1

Ignore the 5-dollar bit. In a testing context, make sure that the event handler of your choice has both a Object and EventArgs requirement, install MoQ, and use the Raise command for the Mocked target.

My Example

Task<CommandResponse> startScanTask = csGO.StartScanAsync();
            await Task.Delay(500);
            MockDriver.Raise(x => x.Received += null, new DataReceivedEventArgs { buffer, length} );

where x refers to the class used to make the interface.