如何对包含数据库事务的代码进行单元测试

Question

How to put unit around the below codes:

public DbContextTransaction QTTransactionBegin()
    {
        return Database.BeginTransaction();
    }

public int CreateCampaign(CreateCampaignModel createCampaignModel)
    {
        using (var transaction = _qtContext.QTTransactionBegin())
        {
            try
            {
                var campaign = new Campaign();
                campaign.CampaignCode = createCampaignModel.CampaignCode;
                campaign.CampaignDescription = createCampaignModel.CampaignDescription;
                campaign.CampaignDate = createCampaignModel.CampaignDate;
                campaign.CampaignNotes = createCampaignModel.CampaignNotes;
                campaign.OwnerUserID = createCampaignModel.OwnerUserID;
                campaign.AddedOn = DateTime.Now;
                campaign.AddedBy = createCampaignModel.OwnerUserName;
                campaign.UpdatedOn = DateTime.Now;
                campaign.UpdatedBy = createCampaignModel.OwnerUserName;
                campaign.CampaignSegments = GetCampaignSegmentList(createCampaignModel);

                var campaignId = AddOrUpdateCampaign(campaign);
                transaction.Commit();
                return campaignId;
            }
            catch (Exception ex)
            {
                transaction.Rollback();
            }
        }
        return 0;
    }

Could anyone advise me how to put unit test around above code ?

I tried the code as below :

Database_database;

    [TestInitialize]
    public void SetUp()
    {
        _qtDALMock = _factory.CreateMock<IQTDAL>();
        _campaignRepository = new CampaignRepository(_qtDALMock.MockObject);
    }
 [TestMethod]
    public void Check_CreateCampaign_Test()
    {
        // arrange 
        const int expectedCampaignId = 1;
        var createCampaign = QueryToolDummies.CreateCampaignModel;

        _database.BeginTransaction();
        _qtDALMock.Expects.One.MethodWith(x => x.QTTransactionBegin())
            .WillReturn(_database.BeginTransaction());
        _qtDALMock.Expects.One.Method(x => x.AddOrUpdateCampaign(null))
            .With(Is.TypeOf<Campaign>())
            .WillReturn(expectedCampaignId);

        // act
        var result = _campaignRepository.CreateCampaign(createCampaign);

        // assert
        Assert.IsNotNull(result);
    }

this _database.BeginTransaction() has a problem. the error says can't use like it.

Please advise.

Answer 1

One question? Why are you trying to start a transaction into a unit test?

Will be easy if you Mock your repository using Moq framework and return what you need to return from the repo.

In fact, I thought that start a BeginTransaction() in a unit test is not a good practice.

I hope this helps

Answer 2

I've experienced the same issue, it's quite tricky to work around.

I tried creating a wrapper class for the context that exposes a BeginTransaction() method, but ultimately you end up needing to mock the DbContextTransaction returned by BeginTransaction() when it comes to testing, but DbContextTransaction has neither an interface or a public constructor.

In the end I wrote a transaction manager class that creates and manages its own transaction and exposes methods for beginning, committing and rolling back the transaction. That manager class, and the service that returns it, can then be faked allowing the code using transactions to be fully tested.

I've written that up fully in this answer .

Answer 3

You are trying to unit test more than one unit.

Assuming that the code above is your 'data layer' / repository then you are performing an integration test because more than a single unit is involved in the test.

You could include setup / teardown for the database within your test class and call the SUT (subject under test) with valid and invalid data to validate expected behaviours.