fix tests and implementation

packages/runtime-core/__tests__/components/Suspense.spec.ts

@@ -1530,7 +1530,7 @@ describe('Suspense', () => {
   })
 
   // #5844
-  test('Suspense + Transition', async () => {
+  test('Suspense + Transition HTML DOM', async () => {
     const InnerA = defineComponent({
       setup: () => {
         const el = ref<HTMLDivElement | null>(null)
@@ -1577,7 +1577,8 @@ describe('Suspense', () => {
             Transition,
             {
               name: 'page',
-              mode: 'out-in'
+              mode: 'out-in',
+              duration: 1
             },
             {
               default: () => [
@@ -1601,15 +1602,120 @@ describe('Suspense', () => {
     const root = document.createElement('div')
     try {
       document.body.appendChild(root)
-      renderDOM(h(Comp), document.body)
-      outerToggle.value = true
-      await nextTick()
+      renderDOM(h(Comp), root)
+      expect(document.body.innerHTML).toContain('innerA')
 
+      outerToggle.value = true
+      // give some time for the transition to finish
+      await new Promise(r => setTimeout(r, 100))
+      expect(document.body.innerHTML).toContain('innerB')
       outerToggle.value = false
-      // delay it more to error from happening on the CI
-      await new Promise(r => setTimeout(r, 10))
+      // give some time for the transition to finish
+      await new Promise(r => setTimeout(r, 100))
+      expect(document.body.innerHTML).toContain('innerA')
+
+      outerToggle.value = true
+
+      // give some time for the transition to finish
+      await new Promise(r => setTimeout(r, 100))
+      expect(document.body.innerHTML).toContain('innerB')
     } finally {
-      document.body.innerHTML = ''
+      document.body.removeChild(root)
     }
   })
+
+  // #5844
+  test('Suspense + Transition', async () => {
+    const expectInnerA = '<div id="innerA">innerA</div>'
+    const expectInnerB = '<div id="innerB">innerB</div>'
+
+    const InnerA = defineComponent({
+      setup: () => {
+        const el = ref<HTMLDivElement | null>(null)
+        onMounted(() => {
+          expect(el.value).toBeTruthy()
+          expect(serializeInner(root)).toBe(expectInnerA)
+        })
+        return () =>
+          h(
+            'div',
+            {
+              ref: el,
+              id: 'innerA'
+            },
+            'innerA'
+          )
+      }
+    })
+
+    const InnerB = defineComponent({
+      setup: () => {
+        const el = ref<HTMLDivElement | null>(null)
+        onMounted(() => {
+          expect(el.value).toBeTruthy()
+          console.log('inner b', serializeInner(root))
+          expect(serializeInner(root)).toBe(expectInnerB)
+        })
+        return () =>
+          h(
+            'div',
+            {
+              ref: el,
+              id: 'innerB'
+            },
+            'innerB'
+          )
+      }
+    })
+    const outerToggle = ref(false)
+
+    const Comp = defineComponent({
+      setup() {
+        return () =>
+          h(
+            Transition,
+            {
+              name: 'page',
+              mode: 'out-in',
+              duration: 1
+            },
+            {
+              default: () => [
+                h(Suspense, null, {
+                  default: [
+                    outerToggle.value
+                      ? h(InnerB, {
+                          key: 1
+                        })
+                      : h(InnerA, {
+                          key: 2
+                        })
+                  ]
+                })
+              ]
+            }
+          )
+      }
+    })
+
+    const root = nodeOps.createElement('div')
+    render(h(Comp), root)
+    expect(serializeInner(root)).toBe(expectInnerA)
+
+    outerToggle.value = true
+    // give some time for the transition to finish
+    await new Promise(r => setTimeout(r, 100))
+    expect(serializeInner(root)).toContain('innerB')
+    outerToggle.value = false
+    // give some time for the transition to finish
+    await new Promise(r => setTimeout(r, 100))
+    expect(serializeInner(root)).toContain('innerA')
+
+    outerToggle.value = true
+
+    // give some time for the transition to finish
+    await new Promise(r => setTimeout(r, 100))
+    expect(serializeInner(root)).toContain('innerB')
+    // }
+  })
 })

packages/runtime-core/src/components/BaseTransition.ts

@@ -511,6 +511,20 @@ export function getTransitionRawChildren(
         getTransitionRawChildren(child.children as VNode[], keepComment, key)
       )
     }
+    // #5844 suspense children should be able to transition
+    else if (child.shapeFlag & ShapeFlags.SUSPENSE) {
+      ret = ret.concat(
+        getTransitionRawChildren(
+          Array.isArray(child.children)
+            ? (child.children as VNode[])
+            : typeof child.children === 'object'
+            ? (child.children?.default as VNode[])
+            : [],
+          keepComment,
+          key
+        )
+      )
+    }
     // comment placeholders should be skipped, e.g. v-if
     else if (keepComment || child.type !== Comment) {
       ret.push(key != null ? cloneVNode(child, { key }) : child)

packages/runtime-test/src/nodeOps.ts

@@ -23,6 +23,10 @@ export interface TestElement {
   children: TestNode[]
   props: Record<string, any>
   eventListeners: Record<string, Function | Function[]> | null
+  classList: {
+    add: (c: string) => void
+    remove: (c: string) => void
+  }
 }
 
 export interface TestText {
@@ -79,7 +83,11 @@ function createElement(tag: string): TestElement {
     children: [],
     props: {},
     parentNode: null,
-    eventListeners: null
+    eventListeners: null,
+    classList: {
+      add(c: string) {},
+      remove(c: string) {}
+    }
   }
   logNodeOp({
     type: NodeOpTypes.CREATE,