Write your first automated test for your own behaviour

How to write a real Play Mode test against your own TsvrcBehaviour subclass, once the testing assemblies are wired into your project, using TsPlayModeTestBase.

Steps

1. Extend TsPlayModeTestBase and start ClientSim in a [UnityTest]:

   public class RoundRefereeTests : TsPlayModeTestBase
   {
       [UnityTest]
       public IEnumerator RoundReferee_StartsOnBegin()
       {
           yield return StartClientSim();

2. Build your project's generated root from code instead of loading a saved scene, and attach a fresh instance of the behaviour under test:

           var builder = BuildTsRoot<TsGenerated>();
           var referee = builder.WithNew<RoundReferee>("RoundReferee");
           builder.Build();

   Any root field your test never touches (a Global, a Pool slot) is auto-filled with a bare stand-in before Build() runs, so a generated stage that unconditionally iterates every field of its module never throws on one your test doesn't care about.

3. Drive the behaviour and assert on it:

           referee.BeginRound();
   
           Assert.IsTrue(referee.IsProcessRunning());
       }
   }

Reaching a private field or method

Use PrivateFieldAccess instead of making something public just so a test can see it:

int remaining = PrivateFieldAccess.GetField<int>(referee, "_remainingMilliseconds");

Asserting an event actually fired

Wire a TsCallbackRecorder as the subscriber instead of writing a one-off listener class for every test:

var recorder = builder.WithNew<TsCallbackRecorder>("Recorder");
referee.TsSubscribe(recorder, RoundReferee.OnRoundEndedEvent, nameof(TsCallbackRecorder.CallbackA));

// ...drive the round to completion...

Assert.AreEqual(1, recorder.CallbackACount);

Why this shape

See Testing your world for the full reasoning behind building a root from code instead of a saved scene, the two Play Mode testing defects patched automatically for any TsPlayModeTestBase subclass, and why the three testing assemblies are split the way they are.