In my test, the connection string is blank after the first call to the database. Why?

Question

I'm using XUnit, FakeItEasy and Dapper. I'm testing a .NET Core 2.1 WebAPI call. When I spin up the actual web site, I have no errors. Something seems to be wrong with my test.

For XUnit I'm using a DatabaseFixture like so:

public class DatabaseFixture : IDisposable
{
    public DatabaseFixture()
    {
        Settings = GetSettings();
        var serviceProvider = CreateServices();

        using (var scope = serviceProvider.CreateScope())
        {
            EnsureDatabase();
            UpdateDatabase(scope.ServiceProvider);
            Db = new SqlConnection(Settings.TestDbConnectionString);
        }
    }
    ...

My web controller looks like this:

    public async Task<ActionResult> Authorization()
    {
        ...
        var user = await _userRepository.FindBySubject(subject);  // <== First call to DB, all good
        if (user == null) return Ok(new { UserNotRegistered = true });

        var roles = await _userRepository.GetRoles(subject); // <== Second call to DB, ConnectionString off of Fake is ""
        ....

        return Ok(roles);
    }

UserRepo looks like this:

public class UserRepository 
{
    ....
    public async Task<Membership> FindByNameAsync(string subject_cn, CancellationToken cancellationToken)
    {
        using (var connection = _connectionFactory.GetConnection())
        {
            return await connection.QuerySingleOrDefaultAsync<Membership>($@"SQL Code", new {subject_cn});
        }
    }

    public async Task<Membership> FindBySubject(string subject_cn)
    {
        return await FindByNameAsync(subject_cn, new CancellationToken());  // First call, all good
    }

    public async Task<IList<string>> GetRoles(string subject_cn)
    {
        var membership = await FindBySubject(subject_cn); //Second call, no connection string :(
        return await GetRolesAsync(membership, new CancellationToken());
    }

And finally and probably most important, my test:

[Collection(nameof(DatabaseFixture))]
public class UserControllerTests
{
    private readonly IDatabaseConnectionFactory _connectionFactory;
    public UserControllerTests(DatabaseFixture fixture)
    {
        _connectionFactory = A.Fake<IDatabaseConnectionFactory>();
        A.CallTo(() => _connectionFactory.GetConnection()).Returns(fixture.Db);
    }

    [Fact]
    public async Task Authorize_ReturnsRoles()
    {
        var configurationManager = A.Fake<IConfigurationManager>();
        A.CallTo(() => configurationManager.GetSettings()).Returns(new Web.Settings() { ... stuff ... });

        var authenticationManager = A.Fake<IAuthenticationManager>();

        var userController = new UserController(new UserRepository(_connectionFactory), authenticationManager, configurationManager);

        var response = await userController.Authorization(); // Connection string is empty on second data call
        var viewResult = Assert.IsType<ViewResult>(response);
        var model = Assert.IsAssignableFrom<AuthorizationResult>(viewResult);

        Assert.Contains("A Role", model.Roles);
        Assert.Equal(AuthorizationResult.UserState.Authenticated, model.Status);
        A.CallTo(() => authenticationManager.AddToRoles(A.Fake<Membership>(), model.Roles)).MustHaveHappened();
        A.CallTo(() => authenticationManager.SignIn(A.Fake<Membership>())).MustHaveHappened();
    }
}

I'm not sure how the fake is "forgetting" the connection string. The specific error being returned is: Message: System.InvalidOperationException : The ConnectionString property has not been initialized. When I debug after the first call, sure enough the connection string on the connection object is blank. Can anyone shed some light on this situation?

Can you check that you're getting the same `SqlConnection` instance in each call? (use the "Make Object Id" debugger feature for this) — Thomas Levesque, Oct 12 '18 at 22:12
@ThomasLevesque let me look that up and see how to do it and I'll let you know. — rball, Oct 12 '18 at 22:59
@ThomasLevesque yes it appears that it's the same SqlConnection instance. Just after the first use the ConnectionString value is blank. — rball, Oct 12 '18 at 23:19
Changed code to A.CallTo(() => _connectionFactory.GetConnection()).Returns(new SqlConnection(settings.TestDbConnectionString)); to try something different, same result. — rball, Oct 12 '18 at 23:47
Try this: `A.CallTo(() => _connectionFactory.GetConnection()).ReturnsLazily(() => new SqlConnection(settings.TestDbConnectionString))`. This will return a new connection for every call. — Thomas Levesque, Oct 13 '18 at 07:45
Anyway, the connection isn't a fake, so I don't think the problem has anything to do with FakeItEasy. — Thomas Levesque, Oct 13 '18 at 07:46
@ThomasLevesque I don't think it's an issue with FakeItEasy per se but I do think that something someplace is removing the connection string property and I'm guessing it is more with how I am setting up the fake itself. The ReturnsLazily seems to have worked. Want to make an answer? — rball, Oct 15 '18 at 17:30

score 0 · Accepted Answer · answered Oct 16 '18 at 11:44

0

I'm not sure exactly what's going on. I don't think the problem is with FakeItEasy, since the connection itself isn't a fake. As a workaround, what you could do is make the fake connection factory return a new connection for every call:

A.CallTo(() => _connectionFactory.GetConnection())
    .ReturnsLazily(() => new SqlConnection(settings.TestDbConnectionString)).

answered Oct 16 '18 at 11:44

Thomas Levesque

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Could be either FakeItEasy or XUnit's fixture doing something wonky. `A.CallTo(() => _connectionFactory.GetConnection()).ReturnsLazily(() => fixture.Db);` still doesn't work. – rball Oct 17 '18 at 19:01

In my test, the connection string is blank after the first call to the database. Why?

1 Answers1