I blogged a little while ago around to support integration tests using Autofac. This was specific to Autofac but documented a workaround for a long standing issue with
ConfigureTestContainer that was introduced into .NET core 3.0 which affects all third-party containers that use
ConfigureTestContainer in their tests.
I'll not repeat the contents of the previous post - it all still stands. However, with Autofac 6 the approach documented there will cease to work. This is because the previous approach relied upon
ContainerBuilder not being sealed. As of Autofac 6 it is.
Using this in place of the previous approach should allow you continue running your integration tests with Autofac 6. Thanks Alistair!
Whilst this gets us back up and running, Alistair pointed out that this approach depends upon a deprecated interface. This is the
IStartupConfigureContainerFilter which has been marked as
Obsolete since mid 2019. What this means is, at some point, this approach will stop working.
The marvellous David Fowler has said that
ConfigureTestContainer issue should be resolved in .NET. However it's worth noting that this has been an issue since .NET Core 3 shipped and unfortunately the wonderful Chris Ross has advised that it's not likely to be fixed for .NET 5.
I'm very keen this does get resolved in .NET. Building tests upon an
Obsolete attribute doesn't fill me with confidence. I'm a long time user of Autofac and I'd like to continue to be. Here's hoping that's made possible by a fix landing in .NET. If this is something you care about, it may be worth upvoting / commenting on the issue in GitHub so the team are aware of desire around this being resolved.