Add unit test for project document JSON serialization

tests/serialization/project-document-json.test.ts

@@ -0,0 +1,69 @@
+import { describe, expect, it } from "vitest";
+
+import {
+  MULTI_SCENE_FOUNDATION_SCENE_DOCUMENT_VERSION,
+  SCENE_DOCUMENT_VERSION,
+  createDefaultSceneLoadingScreenSettings,
+  createEmptyProjectDocument,
+  createEmptyProjectScene
+} from "../../src/document/scene-document";
+import {
+  parseProjectDocumentJson,
+  serializeProjectDocument
+} from "../../src/serialization/scene-document-json";
+
+describe("project document JSON", () => {
+  it("round-trips authored scene loading overlay settings", () => {
+    const document = {
+      ...createEmptyProjectDocument({ sceneName: "Entry" }),
+      activeSceneId: "scene-cellar",
+      scenes: {
+        "scene-main": createEmptyProjectScene({
+          id: "scene-main",
+          name: "Entry"
+        }),
+        "scene-cellar": createEmptyProjectScene({
+          id: "scene-cellar",
+          name: "Cellar",
+          loadingScreen: {
+            colorHex: "#233041",
+            headline: "Descending",
+            description: "Dust and echoes settle before the next room appears."
+          }
+        })
+      }
+    };
+
+    const serializedDocument = serializeProjectDocument(document);
+
+    expect(parseProjectDocumentJson(serializedDocument)).toEqual(document);
+  });
+
+  it("migrates v22 project documents by defaulting missing scene loading overlays", () => {
+    const legacyScene = createEmptyProjectScene({
+      id: "scene-main",
+      name: "Legacy Entry"
+    });
+    const { loadingScreen: _loadingScreen, ...legacySceneWithoutLoadingScreen } =
+      legacyScene;
+    void _loadingScreen;
+
+    const migratedDocument = parseProjectDocumentJson(
+      JSON.stringify({
+        version: MULTI_SCENE_FOUNDATION_SCENE_DOCUMENT_VERSION,
+        activeSceneId: "scene-main",
+        scenes: {
+          "scene-main": legacySceneWithoutLoadingScreen
+        },
+        materials: createEmptyProjectDocument().materials,
+        textures: {},
+        assets: {}
+      })
+    );
+
+    expect(migratedDocument.version).toBe(SCENE_DOCUMENT_VERSION);
+    expect(migratedDocument.scenes["scene-main"]?.loadingScreen).toEqual(
+      createDefaultSceneLoadingScreenSettings()
+    );
+  });
+});