update tests as per comments

app/shared/tree-utils/create-instance.test.ts

@@ -4,29 +4,28 @@ describe("create instance", () => {
   test("instance without id should be auto generated", () => {
     const createdInstance = createInstance({
       component: "Box",
-      id: undefined,
-      children: [],
-      style: {},
     });
 
-    // We cannot do snapshot testing here as the id will always be unique
-    expect(createdInstance.id).toBeDefined();
+    expect(typeof createdInstance.id).toBe("string");
   });
 
   test("instance without children should be empty by default", () => {
     const createdInstance = createInstance({
       component: "Box",
-      id: undefined,
-      children: undefined,
-      style: {},
     });
     expect(createdInstance.children.length).toBe(0);
   });
 
+  test("instance without style should be an object after creation", () => {
+    const createdInstance = createInstance({
+      component: "Box",
+    });
+    expect(typeof createdInstance.style).toBe("object");
+  });
+
   test("instance with children ", () => {
     const createdInstance = createInstance({
       component: "Box",
-      id: undefined,
       children: [
         {
           id: "1",
@@ -37,6 +36,13 @@ describe("create instance", () => {
       ],
       style: {},
     });
-    expect(createdInstance.children.length).toBe(1);
+    expect(createdInstance.children).toEqual([
+      {
+        id: "1",
+        component: "Box",
+        style: {},
+        children: [],
+      },
+    ]);
   });
 });