Fix overlapping act call when using cleanup

Author: Sebastian Silbermann

Diff for: src/__tests__/cleanup.js

@@ -41,6 +41,18 @@ test('cleanup runs effect cleanup functions', async () => {
   expect(spy).toHaveBeenCalledTimes(1)
 })
 
+test('cleanup cleans up every root and disconnects containers', async () => {
+  const {container: container1} = await render(<div />)
+  const {container: container2} = await render(<span />)
+
+  await cleanup()
+
+  expect(container1).toBeEmptyDOMElement()
+  expect(container1.isConnected).toBe(false)
+  expect(container2).toBeEmptyDOMElement()
+  expect(container2.isConnected).toBe(false)
+})
+
 describe('fake timers and missing act warnings', () => {
   beforeEach(() => {
     jest.resetAllMocks()

Diff for: src/pure.js

@@ -239,16 +239,14 @@ async function render(
 }
 
 async function cleanup() {
-  await Promise.all(
-    mountedRootEntries.map(async ({root, container}) => {
-      await act(() => {
-        root.unmount()
-      })
-      if (container.parentNode === document.body) {
-        document.body.removeChild(container)
-      }
-    }),
-  )
+  for (const {container, root} of mountedRootEntries) {
+    // eslint-disable-next-line no-await-in-loop -- Overlapping act calls are not allowed.
+    await root.unmount()
+    if (container.parentNode === document.body) {
+      document.body.removeChild(container)
+    }
+  }
+
   mountedRootEntries.length = 0
   mountedContainers.clear()
 }