fix(core): add editor cleanup in BlockNoteEditor.test.ts to prevent unhandled DOMObserver errors (#2816)

Tests that mount editors were not calling unmount() afterward, leaving
ProseMirror's DOMObserver timers active. When prosemirror-view is updated
to newer versions (e.g. 1.41.8 via fresh dep resolution), a dangling
setTimeout in DOMObserver.flush() fires after jsdom teardown, causing
'document is not defined' ReferenceError.

Add afterEach cleanup following the same pattern as transformPasted.test.ts.

Author: nperez0111

packages/core/src/editor/BlockNoteEditor.test.ts

@@ -1,4 +1,4 @@
-import { expect, it } from "vitest";
+import { afterEach, expect, it } from "vitest";
 import * as Y from "yjs";
 
 import {
@@ -11,15 +11,27 @@ import { BlocksChanged } from "../api/getBlocksChangedByTransaction.js";
 /**
  * @vitest-environment jsdom
  */
+
+const editorsToCleanup: BlockNoteEditor<any, any, any>[] = [];
+
+afterEach(() => {
+  for (const editor of editorsToCleanup) {
+    editor.unmount();
+  }
+  editorsToCleanup.length = 0;
+});
+
 it("creates an editor", () => {
   const editor = BlockNoteEditor.create();
+  editorsToCleanup.push(editor);
   const posInfo = editor.transact((tr) => getNearestBlockPos(tr.doc, 2));
   const info = getBlockInfo(posInfo);
   expect(info.blockNoteType).toEqual("paragraph");
 });
 
 it("immediately replaces doc", async () => {
   const editor = BlockNoteEditor.create();
+  editorsToCleanup.push(editor);
   const blocks = await editor.tryParseMarkdownToBlocks(
     "This is a normal text\n\n# And this is a large heading",
   );
@@ -70,6 +82,7 @@ it("adds id attribute when requested", async () => {
   const editor = BlockNoteEditor.create({
     setIdAttribute: true,
   });
+  editorsToCleanup.push(editor);
   const blocks = await editor.tryParseMarkdownToBlocks(
     "This is a normal text\n\n# And this is a large heading",
   );
@@ -81,6 +94,7 @@ it("adds id attribute when requested", async () => {
 
 it("updates block", () => {
   const editor = BlockNoteEditor.create();
+  editorsToCleanup.push(editor);
   editor.updateBlock(editor.document[0], {
     content: "hello",
   });
@@ -89,6 +103,7 @@ it("updates block", () => {
 it("block prop types", () => {
   // this test checks whether the block props are correctly typed in typescript
   const editor = BlockNoteEditor.create();
+  editorsToCleanup.push(editor);
   const block = editor.document[0];
   if (block.type === "paragraph") {
     // @ts-expect-error
@@ -108,6 +123,7 @@ it("block prop types", () => {
 
 it("onMount and onUnmount", async () => {
   const editor = BlockNoteEditor.create();
+  editorsToCleanup.push(editor);
   let mounted = false;
   let unmounted = false;
   editor.onMount(() => {
@@ -143,6 +159,7 @@ it("sets an initial block id when using Y.js", async () => {
       },
     },
   });
+  editorsToCleanup.push(editor);
 
   editor.mount(document.createElement("div"));
 
@@ -193,6 +210,7 @@ it("sets an initial block id when using Y.js", async () => {
 
 it("onBeforeChange", () => {
   const editor = BlockNoteEditor.create();
+  editorsToCleanup.push(editor);
   let beforeChangeCalled = false;
   let changes: BlocksChanged<any, any, any> = [];
   editor.onBeforeChange(({ getChanges }) => {