Unit Tests

Unit Testing with Dovetails

Dovetail offers some great magic but without being able to write unit tests, then the magic hurts more than it might help.

Unit Tests can be written many different ways.

Use xref:Joinery.Dovetail.DovetailContextBuilder directly

You can make use of the xref:Joinery.Dovetail.DovetailContextBuilder by itself, and apply all the joints. This requires more manual configuration but gives the greatest flexibility.

[!code-c#Sample Test]

Use xref:Joinery.Dovetail.Hosting.TestHost

The xref:Joinery.Dovetail.Hosting.TestHost can be used to create a IHostBuilder configured for testing. This will automatically do the work for setting up Configuration, Services and Logging.

[!code-c#Sample Test]

Tip

There is xref:Joinery.Dovetail.WebAssembly.Hosting.TestWebAssemblyHost for WebAssembly / Blazor apps

Logging

Some unit testing frameworks have the ability to capture log output for a given test, this can be handy for helping identify any problems.

Dovetail itself does not log while it scans and applies joints. xref:Joinery.Dovetail.DovetailContextBuilder and xref:Joinery.Dovetail.IDovetailContext take no ILogger or ILoggerFactory, and nothing in the packages looks for one, so a logger given to either produces no diagnostic output about the scan. What a test can capture is what your own code logs, including your joints.

Tip

With TUnit, use the TestRecord from Rocket.Surgery.Extensions.Testing.TUnit (as in AutoFakeTest<TestRecord>): its Serilog logger writes to the test’s output.

The builder is a bag of properties, so the test can put its logger there for a joint to find:

// In the test, where Logger is the test's Serilog logger.
builder.Set(Logger);

// In the joint under test.
public class AuditJoint : IServiceJoint
{
    public void Register(IDovetailContext context, IServiceCollection services) =>
        context.Get<Serilog.ILogger>()?.Information("Registering the audit services");
}

A joint can also take the logger as a constructor parameter, as described in Injecting dependencies. In an application, as opposed to a test, the sinks and enrichers of the logger are configured by the Serilog joint.