diff --git a/tests/unit/runtime-host.test.ts b/tests/unit/runtime-host.test.ts
new file mode 100644
index 00000000..e4d42bac
--- /dev/null
+++ b/tests/unit/runtime-host.test.ts
@@ -0,0 +1,84 @@
+import { waitFor } from "@testing-library/react";
+import { afterEach, describe, expect, it, vi } from "vitest";
+
+import { createEmptySceneDocument } from "../../src/document/scene-document";
+import { RapierCollisionWorld } from "../../src/runtime-three/rapier-collision-world";
+import {
+  RuntimeHost,
+  type RuntimeSceneLoadState
+} from "../../src/runtime-three/runtime-host";
+import { buildRuntimeSceneFromDocument } from "../../src/runtime-three/runtime-scene-build";
+
+function createDeferred<T>() {
+  let resolve: ((value: T) => void) | null = null;
+  let reject: ((error: unknown) => void) | null = null;
+  const promise = new Promise<T>((innerResolve, innerReject) => {
+    resolve = innerResolve;
+    reject = innerReject;
+  });
+
+  return {
+    promise,
+    resolve(value: T) {
+      resolve?.(value);
+    },
+    reject(error: unknown) {
+      reject?.(error);
+    }
+  };
+}
+
+describe("RuntimeHost", () => {
+  afterEach(() => {
+    vi.restoreAllMocks();
+  });
+
+  it("delays controller activation until collision setup reports the scene as ready", async () => {
+    const runtimeScene = buildRuntimeSceneFromDocument(createEmptySceneDocument());
+    const collisionWorld = {
+      dispose: vi.fn()
+    } as unknown as RapierCollisionWorld;
+    const deferredCollisionWorld = createDeferred<RapierCollisionWorld>();
+    vi.spyOn(RapierCollisionWorld, "create").mockReturnValue(
+      deferredCollisionWorld.promise
+    );
+
+    const runtimeMessages: Array<string | null> = [];
+    const sceneLoadStates: RuntimeSceneLoadState[] = [];
+    const host = new RuntimeHost({
+      enableRendering: false
+    });
+    host.setRuntimeMessageHandler((message) => {
+      runtimeMessages.push(message);
+    });
+    host.setSceneLoadStateHandler((state) => {
+      sceneLoadStates.push(state);
+    });
+
+    host.loadScene(runtimeScene);
+    host.setNavigationMode("orbitVisitor");
+
+    expect(sceneLoadStates).toEqual([
+      {
+        status: "loading",
+        message: null
+      }
+    ]);
+    expect(runtimeMessages).toEqual([null]);
+
+    deferredCollisionWorld.resolve(collisionWorld);
+
+    await waitFor(() => {
+      expect(sceneLoadStates).toContainEqual({
+        status: "ready",
+        message: null
+      });
+      expect(runtimeMessages).toContain(
+        "Orbit Visitor active. Drag to orbit around the scene and use the mouse wheel to zoom."
+      );
+    });
+
+    host.dispose();
+    expect(collisionWorld.dispose).toHaveBeenCalledTimes(1);
+  });
+});