Unit test case for service and script package

Author: vishnuv688

packages/script/tests/utils.test.ts

@@ -0,0 +1,140 @@
+/**
+ * @vitest-environment happy-dom
+ */
+import { describe, it, expect, beforeEach } from 'vitest'
+import {
+  waitForBody,
+  assignRef,
+  getRef,
+  parseFragment,
+  parseDocument
+} from '../src/utils.js'
+
+describe('DOM mutation capture utilities', () => {
+  beforeEach(() => {
+    if (!document.body) {
+      const body = document.createElement('body')
+      document.documentElement.appendChild(body)
+    }
+    document.body.innerHTML = ''
+  })
+
+  it('should wait for body to exist before capturing mutations', async () => {
+    await expect(waitForBody()).resolves.toBeUndefined()
+  })
+
+  it('should assign trackable refs to DOM elements for mutation identification', () => {
+    const parent = document.createElement('div')
+    const child1 = document.createElement('span')
+    const child2 = document.createElement('p')
+    parent.appendChild(child1)
+    parent.appendChild(child2)
+
+    assignRef(parent)
+
+    const parentRef = getRef(parent)
+    const child1Ref = getRef(child1)
+    const child2Ref = getRef(child2)
+
+    // Each element should get unique ref
+    expect(parentRef).toBeTruthy()
+    expect(child1Ref).toBeTruthy()
+    expect(child2Ref).toBeTruthy()
+    expect(parentRef).not.toBe(child1Ref)
+    expect(child1Ref).not.toBe(child2Ref)
+  })
+
+  it('should maintain stable refs across multiple assignments', () => {
+    const div = document.createElement('div')
+    assignRef(div)
+    const firstRef = getRef(div)
+
+    assignRef(div)
+    const secondRef = getRef(div)
+
+    expect(firstRef).toBe(secondRef)
+  })
+
+  it('should serialize DOM elements to transmittable VNode structure', () => {
+    const button = document.createElement('button')
+    button.id = 'submit'
+    button.className = 'btn-primary'
+    button.textContent = 'Submit'
+
+    const vnode = parseFragment(button)
+
+    // VNode should be serializable (has type and props)
+    expect(vnode).toHaveProperty('type')
+    expect(vnode).toHaveProperty('props')
+    expect(JSON.stringify(vnode)).toBeTruthy()
+  })
+
+  it('should serialize complete document hierarchy for initial capture', () => {
+    const div = document.createElement('div')
+    div.innerHTML = '<header><h1>App</h1></header><main><p>Content</p></main>'
+
+    const vnode = parseDocument(div)
+
+    // Document parsing wraps in html element
+    expect(vnode).toHaveProperty('type')
+    expect(vnode).toHaveProperty('props')
+    expect(JSON.stringify(vnode)).toBeTruthy()
+  })
+
+  it('should handle parsing errors without breaking mutation capture', () => {
+    const fragmentResult = parseFragment(null as any)
+    const documentResult = parseDocument(null as any)
+
+    // Should return error containers instead of throwing
+    expect(typeof fragmentResult).toBe('object')
+    expect(typeof documentResult).toBe('object')
+
+    if (typeof fragmentResult === 'object') {
+      expect(fragmentResult.type).toBe('div')
+      expect(fragmentResult.props.class).toBe('parseFragmentWrapper')
+    }
+
+    if (typeof documentResult === 'object') {
+      expect(documentResult.type).toBe('div')
+      expect(documentResult.props.class).toBe('parseDocument')
+    }
+  })
+
+  it('should support complete mutation tracking workflow: assign ref → serialize → transmit', () => {
+    // Simulate what happens in index.ts when MutationObserver detects changes
+    const addedNode = document.createElement('article')
+    addedNode.innerHTML = '<h2>New Section</h2><p>New content</p>'
+
+    // Step 1: Assign ref so we can track this node
+    assignRef(addedNode)
+    const nodeRef = getRef(addedNode)
+
+    // Step 2: Serialize for transmission to backend
+    const serialized = parseFragment(addedNode)
+
+    // Step 3: Verify we can identify and serialize the mutation
+    expect(nodeRef).toBeTruthy()
+    expect(serialized).toHaveProperty('type')
+    expect(serialized).toHaveProperty('props')
+
+    // The serialized VNode should be transmittable as JSON
+    const json = JSON.stringify(serialized)
+    expect(json).toBeTruthy()
+    expect(() => JSON.parse(json)).not.toThrow()
+  })
+
+  it('should support mutation removal tracking via refs', () => {
+    const target = document.createElement('div')
+    const child = document.createElement('span')
+    target.appendChild(child)
+
+    assignRef(target)
+
+    // When mutation observer detects removals, we can get refs
+    const targetRef = getRef(target)
+    const childRef = getRef(child)
+
+    expect(targetRef).not.toBeNull()
+    expect(childRef).not.toBeNull()
+  })
+})