Add tests for world settings command and helpers

tests/domain/world-settings.command.test.ts

@@ -0,0 +1,33 @@
+import { describe, expect, it } from "vitest";
+
+import { createEditorStore } from "../../src/app/editor-store";
+import { createSetWorldSettingsCommand } from "../../src/commands/set-world-settings-command";
+import { createEmptySceneDocument } from "../../src/document/scene-document";
+import { cloneWorldSettings } from "../../src/document/world-settings";
+
+describe("createSetWorldSettingsCommand", () => {
+  it("updates authored world settings and restores them through undo", () => {
+    const store = createEditorStore();
+    const originalWorld = cloneWorldSettings(store.getState().document.world);
+    const nextWorld = cloneWorldSettings(originalWorld);
+
+    nextWorld.background = {
+      mode: "verticalGradient",
+      topColorHex: "#6e8db4",
+      bottomColorHex: "#18212b"
+    };
+    nextWorld.ambientLight.intensity = 0.45;
+
+    store.executeCommand(
+      createSetWorldSettingsCommand({
+        label: "Set world lighting",
+        world: nextWorld
+      })
+    );
+
+    expect(store.getState().document.world).toEqual(nextWorld);
+
+    expect(store.undo()).toBe(true);
+    expect(store.getState().document.world).toEqual(createEmptySceneDocument().world);
+  });
+});