Split up test project

Robust.UnitTesting was both ALL tests for RT, and also API surface for content tests.

Tests are now split into separate projects as appropriate, and the API side has also been split off.

Robust.Shared.IntegrationTests/GameObjects/IEntityManagerTests.cs

@@ -0,0 +1,52 @@
+using System.Numerics;
+using NUnit.Framework;
+using Robust.Shared.GameObjects;
+using Robust.Shared.Map;
+using Robust.Shared.Serialization.Manager.Attributes;
+using Robust.UnitTesting.Server;
+
+namespace Robust.UnitTesting.Shared.GameObjects
+{
+    [TestFixture, Parallelizable]
+    sealed partial class EntityManagerTests
+    {
+        private static ISimulation SimulationFactory()
+        {
+            var sim = RobustServerSimulation
+                .NewSimulation()
+                .InitializeInstance();
+
+            return sim;
+        }
+
+        /// <summary>
+        /// The entity prototype can define field on the TransformComponent, just like any other component.
+        /// </summary>
+        [Test]
+        public void SpawnEntity_PrototypeTransform_Works()
+        {
+            var sim = SimulationFactory();
+            var map = sim.CreateMap().MapId;
+
+            var entMan = sim.Resolve<IEntityManager>();
+            var newEnt = entMan.SpawnEntity(null, new MapCoordinates(0, 0, map));
+            Assert.That(newEnt, Is.Not.EqualTo(EntityUid.Invalid));
+        }
+
+        [Test]
+        public void ComponentCount_Works()
+        {
+            var sim = RobustServerSimulation.NewSimulation().InitializeInstance();
+
+            var entManager = sim.Resolve<IEntityManager>();
+            var mapSystem = entManager.System<SharedMapSystem>();
+
+            Assert.That(entManager.Count<TransformComponent>(), Is.EqualTo(0));
+
+            var mapId = sim.CreateMap().MapId;
+            Assert.That(entManager.Count<TransformComponent>(), Is.EqualTo(1));
+            mapSystem.DeleteMap(mapId);
+            Assert.That(entManager.Count<TransformComponent>(), Is.EqualTo(0));
+        }
+    }
+}