CODEWITHSUNDEEP
c#mysqltestingmockingxunit
Diego Perez
Diego Perez

Reputation: 2862

.Net 8 XUnit: Mocking MySql connection and different service implementation for unit testing

I'm working on a .Net 8 API and I'm currently creating tests, and my concern is about mocking the connection to the MySql database.

We use CQRS (Mediator pattern) and in the queries handler (what I have to test) a IMySqlConnectionFactory is injected.

This IMySqlConnectionFactory has three methods, one to create the connection, another to do a query with filter, and a third to execute a MySql statement.

IMySqlConnectionFactory:

public interface IMySqlConnectionFactory
{
    DbConnection CreateConnection(Region region);

    Task<(int Count, TOut[] Data)> QuerySearchAsync<TDbItem, TOut>(IRegionRepository regionRepository, string fetchDataQuery, string? countDataQuery = null, Dictionary<string, string>? columnModelModel = null, Paging? paging = null, ColumnName[]? order = null, string[]? excludedOrder = null, Func<Region, TDbItem, TOut>? transform = null, object? queryParam = null, Func<Region, bool>? filter = null, bool skipDbPaging = false, CancellationToken ct = default(CancellationToken)) where TOut : class;

    Task<int> ExecuteAsync(IRegionRepository regionRepository, string sql, object? @params = null, Func<Region, bool>? filter = null, CancellationToken ct = default(CancellationToken));
}

And that Interface is being registered in

Program.cs:

await RunServer.RunAsync<Startup>(
    args,
    (builder, options) =>
    {
        options.OtherServices = () =>
        {
            ...
            builder.Services.AddScoped<IMySqlConnectionFactory, MySqlCloudStackCoreConnectionFactory>();
        };
    }
);

My issue is I don't know how to override that service registration so when I'm testing it registers a different implementation (we use XUnit for the tests), and also how should I mock the MySQL connection so it connects to a fake database with data I will mock myself..

We are already doing this with SQL Server and it's working great, but it's quite a complex implementation one of my companions developed and I don't know how to replicate in MySQL.

In resume I need to register a different implementation for a DbConnectionFactory where in the end the query and execute methods would be intact, but I would only define a mock MySQL connection.

I have to stick to the IMySqlConnectionFactory interface, because all our cqrs handlers use that for the queries. What can I try next?

Upvotes: 0

Views: 136

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