test: add tests for can() method

tests/cypress/integration/core/can.spec.ts

@@ -0,0 +1,73 @@
+/// <reference types="cypress" />
+
+import { Editor } from '@tiptap/core'
+import Document from '@tiptap/extension-document'
+import Paragraph from '@tiptap/extension-paragraph'
+import Text from '@tiptap/extension-text'
+import History from '@tiptap/extension-history'
+
+describe('can', () => {
+  it('not undo', () => {
+    const editor = new Editor({
+      extensions: [
+        Document,
+        Paragraph,
+        Text,
+        History,
+      ],
+    })
+
+    const canUndo = editor.can().undo()
+
+    expect(canUndo).to.eq(false)
+  })
+
+  it('undo', () => {
+    const editor = new Editor({
+      extensions: [
+        Document,
+        Paragraph,
+        Text,
+        History,
+      ],
+    })
+
+    editor.commands.setContent('foo')
+
+    const canUndo = editor.can().undo()
+
+    expect(canUndo).to.eq(true)
+  })
+
+  it('not chain undo', () => {
+    const editor = new Editor({
+      extensions: [
+        Document,
+        Paragraph,
+        Text,
+        History,
+      ],
+    })
+
+    const canUndo = editor.can().chain().undo().run()
+
+    expect(canUndo).to.eq(false)
+  })
+
+  it('chain undo', () => {
+    const editor = new Editor({
+      extensions: [
+        Document,
+        Paragraph,
+        Text,
+        History,
+      ],
+    })
+
+    editor.commands.setContent('foo')
+
+    const canUndo = editor.can().chain().undo().run()
+
+    expect(canUndo).to.eq(true)
+  })
+})