[TestUtils.act] warn when using TestUtils.act in node (#14768)

* warn when using TestUtils.act in node

* s/warns/throws

* s/throw/warn

* consistent ellipses

src/__tests__/ReactTestRenderer-test.internal.js

@@ -1023,7 +1023,7 @@ describe('ReactTestRenderer', () => {
   });
 
   describe('act', () => {
-    it('works', () => {
+    it('can use .act() to batch updates and effects', () => {
       function App(props) {
         React.useEffect(() => {
           props.callback();
@@ -1043,5 +1043,19 @@ describe('ReactTestRenderer', () => {
 
       expect(called).toBe(true);
     });
+    it('warns and throws if you use TestUtils.act instead of TestRenderer.act in node', () => {
+      // we warn when you try to load 2 renderers in the same 'scope'
+      // so as suggested, we call resetModules() to carry on with the test
+      jest.resetModules();
+      const {act} = require('react-dom/test-utils');
+      expect(() => {
+        expect(() => act(() => {})).toThrow('document is not defined');
+      }).toWarnDev(
+        [
+          'It looks like you called TestUtils.act(...) in a non-browser environment',
+        ],
+        {withoutStack: 1},
+      );
+    });
   });
 });