diff --git a/packages/runtime-vapor/__tests__/dom/patchProp.spec.ts b/packages/runtime-vapor/__tests__/dom/patchProp.spec.ts
new file mode 100644
index 000000000..75b78c8bf
--- /dev/null
+++ b/packages/runtime-vapor/__tests__/dom/patchProp.spec.ts
@@ -0,0 +1,220 @@
+import { NOOP } from '@vue/shared'
+import {
+  setDynamicProp as _setDynamicProp,
+  recordPropMetadata,
+  setAttr,
+  setClass,
+  setDOMProp,
+  setHtml,
+  setStyle,
+  setText,
+} from '../../src'
+import {
+  createComponentInstance,
+  currentInstance,
+  getCurrentInstance,
+  setCurrentInstance,
+} from '../../src/component'
+
+let removeComponentInstance = NOOP
+beforeEach(() => {
+  const reset = setCurrentInstance(createComponentInstance((() => {}) as any))
+  removeComponentInstance = () => {
+    reset()
+    removeComponentInstance = NOOP
+  }
+})
+afterEach(() => {
+  removeComponentInstance()
+})
+
+describe('patchProp', () => {
+  describe('recordPropMetadata', () => {
+    test('should record prop metadata', () => {
+      const node = {} as Node // the node is just a key
+      let prev = recordPropMetadata(node, 'class', 'foo')
+      expect(prev).toBeUndefined()
+      prev = recordPropMetadata(node, 'class', 'bar')
+      expect(prev).toBe('foo')
+      prev = recordPropMetadata(node, 'style', 'color: red')
+      expect(prev).toBeUndefined()
+      prev = recordPropMetadata(node, 'style', 'color: blue')
+      expect(prev).toBe('color: red')
+
+      expect(getCurrentInstance()?.metadata.get(node)).toEqual({
+        props: { class: 'bar', style: 'color: blue' },
+      })
+    })
+
+    test('should have different metadata for different nodes', () => {
+      const node1 = {} as Node
+      const node2 = {} as Node
+      recordPropMetadata(node1, 'class', 'foo')
+      recordPropMetadata(node2, 'class', 'bar')
+      expect(getCurrentInstance()?.metadata.get(node1)).toEqual({
+        props: { class: 'foo' },
+      })
+      expect(getCurrentInstance()?.metadata.get(node2)).toEqual({
+        props: { class: 'bar' },
+      })
+    })
+
+    test('should not record prop metadata outside of component', () => {
+      removeComponentInstance()
+      expect(currentInstance).toBeNull()
+
+      // FIXME
+      expect(() => recordPropMetadata({} as Node, 'class', 'foo')).toThrowError(
+        'cannot be used out of component',
+      )
+    })
+  })
+
+  describe('setClass', () => {
+    test('should set class', () => {
+      const el = document.createElement('div')
+      setClass(el, 'foo')
+      expect(el.className).toBe('foo')
+      setClass(el, ['bar', 'baz'])
+      expect(el.className).toBe('bar baz')
+      setClass(el, { a: true, b: false })
+      expect(el.className).toBe('a')
+    })
+  })
+
+  describe('setStyle', () => {
+    test('should set style', () => {
+      const el = document.createElement('div')
+      setStyle(el, 'color: red')
+      expect(el.style.cssText).toBe('color: red;')
+    })
+    test.fails('shoud set style with object and array property', () => {
+      const el = document.createElement('div')
+      setStyle(el, { color: 'red' })
+      expect(el.style.cssText).toBe('color: red;')
+      setStyle(el, [{ color: 'blue' }, { fontSize: '12px' }])
+      expect(el.style.cssText).toBe('color: blue; font-size: 12px;')
+    })
+  })
+
+  describe('setAttr', () => {
+    test('should set attribute', () => {
+      const el = document.createElement('div')
+      setAttr(el, 'id', 'foo')
+      expect(el.getAttribute('id')).toBe('foo')
+      setAttr(el, 'name', 'bar')
+      expect(el.getAttribute('name')).toBe('bar')
+    })
+
+    test('should remove attribute', () => {
+      const el = document.createElement('div')
+      setAttr(el, 'id', 'foo')
+      setAttr(el, 'data', 'bar')
+      expect(el.getAttribute('id')).toBe('foo')
+      expect(el.getAttribute('data')).toBe('bar')
+      setAttr(el, 'id', null)
+      expect(el.getAttribute('id')).toBeNull()
+      setAttr(el, 'data', undefined)
+      expect(el.getAttribute('data')).toBeNull()
+    })
+
+    test('should set boolean attribute to string', () => {
+      const el = document.createElement('div')
+      setAttr(el, 'disabled', true)
+      expect(el.getAttribute('disabled')).toBe('true')
+      setAttr(el, 'disabled', false)
+      expect(el.getAttribute('disabled')).toBe('false')
+    })
+  })
+
+  describe('setDOMProp', () => {
+    test('should set DOM property', () => {
+      const el = document.createElement('div')
+      setDOMProp(el, 'textContent', 'foo')
+      expect(el.textContent).toBe('foo')
+      setDOMProp(el, 'innerHTML', '<p>bar</p>')
+      expect(el.innerHTML).toBe('<p>bar</p>')
+    })
+  })
+
+  describe('setDynamicProp', () => {
+    const element = document.createElement('div')
+    function setDynamicProp(
+      key: string,
+      value: any,
+      el = element.cloneNode(true) as HTMLElement,
+    ) {
+      _setDynamicProp(el, key, value)
+      return el
+    }
+
+    test('should be able to set id', () => {
+      let res = setDynamicProp('id', 'bar')
+      expect(res.id).toBe('bar')
+    })
+
+    test('should be able to set class', () => {
+      let res = setDynamicProp('class', 'foo')
+      expect(res.className).toBe('foo')
+    })
+
+    test('should be able to set style', () => {
+      let res = setDynamicProp('style', 'color: red')
+      expect(res.style.cssText).toBe('color: red;')
+    })
+
+    test('should be able to set .prop', () => {
+      let res = setDynamicProp('.foo', 'bar')
+      expect((res as any)['foo']).toBe('bar')
+      expect(res.getAttribute('foo')).toBeNull()
+    })
+
+    test('should be able to set ^attr', () => {
+      let res = setDynamicProp('^foo', 'bar')
+      expect(res.getAttribute('foo')).toBe('bar')
+      expect((res as any)['foo']).toBeUndefined()
+    })
+
+    test('should be able to set boolean prop', () => {
+      let res = setDynamicProp(
+        'disabled',
+        true,
+        document.createElement('button'),
+      )
+      expect(res.getAttribute('disabled')).toBe('')
+      setDynamicProp('disabled', false, res)
+      expect(res.getAttribute('disabled')).toBeNull()
+    })
+
+    // The function shouldSetAsProp has complete tests elsewhere,
+    // so here we only do a simple test.
+    test('should be able to set innerHTML and textContent', () => {
+      let res = setDynamicProp('innerHTML', '<p>bar</p>')
+      expect(res.innerHTML).toBe('<p>bar</p>')
+      res = setDynamicProp('textContent', 'foo')
+      expect(res.textContent).toBe('foo')
+    })
+
+    test.todo('should be able to set something on SVG')
+  })
+
+  describe('setText', () => {
+    test('should set textContent', () => {
+      const el = document.createElement('div')
+      setText(el, 'foo')
+      expect(el.textContent).toBe('foo')
+      setText(el, 'bar')
+      expect(el.textContent).toBe('bar')
+    })
+  })
+
+  describe('setHtml', () => {
+    test('should set innerHTML', () => {
+      const el = document.createElement('div')
+      setHtml(el, '<p>foo</p>')
+      expect(el.innerHTML).toBe('<p>foo</p>')
+      setHtml(el, '<p>bar</p>')
+      expect(el.innerHTML).toBe('<p>bar</p>')
+    })
+  })
+})
diff --git a/packages/runtime-vapor/src/dom/patchProp.ts b/packages/runtime-vapor/src/dom/patchProp.ts
index d877afbd3..29d699024 100644
--- a/packages/runtime-vapor/src/dom/patchProp.ts
+++ b/packages/runtime-vapor/src/dom/patchProp.ts
@@ -7,6 +7,21 @@ import {
 } from '@vue/shared'
 import { currentInstance } from '../component'
 
+export function recordPropMetadata(el: Node, key: string, value: any): any {
+  if (!currentInstance) {
+    // TODO implement error handling
+    if (__DEV__) throw new Error('cannot be used out of component')
+    return
+  }
+  let metadata = currentInstance.metadata.get(el)
+  if (!metadata) {
+    currentInstance.metadata.set(el, (metadata = { props: {} }))
+  }
+  const prev = metadata.props[key]
+  metadata.props[key] = value
+  return prev
+}
+
 export function setClass(el: Element, value: any) {
   const prev = recordPropMetadata(el, 'class', (value = normalizeClass(value)))
   if (value !== prev && (value || prev)) {
@@ -65,18 +80,6 @@ export function setDynamicProp(el: Element, key: string, value: any) {
   }
 }
 
-export function recordPropMetadata(el: Node, key: string, value: any): any {
-  if (currentInstance) {
-    let metadata = currentInstance.metadata.get(el)
-    if (!metadata) {
-      currentInstance.metadata.set(el, (metadata = { props: {} }))
-    }
-    const prev = metadata.props[key]
-    metadata.props[key] = value
-    return prev
-  }
-}
-
 export function setText(el: Node, value: any) {
   const oldVal = recordPropMetadata(
     el,