fix(react): Fix $unmount throwing in a non React test

It's common to call `$unmount` in a `beforeEach` hook to run in every
test, and, before, it would throw for tests that never called `$render`.

Author: NiGhTTraX

Diff for: packages/react/src/render.ts

@@ -64,6 +64,10 @@ export function $rerender(element: ReactElement): JQuery {
  */
 export function $unmount() {
   act(() => {
+    if (!rootUnmount) {
+      return;
+    }
+
     rootUnmount();
   });
 }

Diff for: packages/react/tests/render.spec.tsx

@@ -3,7 +3,7 @@ import React, { useEffect, useState } from 'react';
 import createReactMock from 'react-mock-component';
 import { expect } from 'tdd-buffet/expect/jest';
 import { describe, it } from 'tdd-buffet/suite/node';
-import { $render, $rerender, $unmount } from '../src/render';
+import { $render, $rerender } from '../src/render';
 
 describe('$render', () => {
   it('should render a component', () => {
@@ -105,54 +105,4 @@ describe('$render', () => {
 
     expect($component.text()).toEqual('12');
   });
-
-  it('should unmount component', () => {
-    let unmounted = false;
-
-    class Unmountable extends React.Component {
-      render() {
-        return null;
-      }
-
-      componentWillUnmount() {
-        unmounted = true;
-      }
-    }
-
-    $render(<Unmountable />);
-    $unmount();
-
-    expect(unmounted).toBeTruthy();
-  });
-
-  it('should recreate container after unmounting', () => {
-    const $container = $render(<span>bar</span>);
-    $unmount();
-    const $newContainer = $render(<span>baz</span>);
-
-    expect($container.text()).toHaveLength(0);
-    expect($newContainer.text()).toEqual('baz');
-  });
-
-  it('should cleanup after unmounting', () => {
-    let flushed = false;
-
-    const Foo = () => {
-      useEffect(() => () => {
-        flushed = true;
-      });
-
-      return null;
-    };
-
-    $render(<Foo />);
-    $unmount();
-
-    expect(flushed).toBeTruthy();
-  });
-
-  it('should not blow up if unmounting nothing', () => {
-    $unmount();
-    $unmount();
-  });
 });

Diff for: packages/react/tests/unmount.spec.tsx

@@ -0,0 +1,54 @@
+import React, { useEffect } from 'react';
+import { $render, $unmount } from '../src/render';
+
+describe('unmount', () => {
+  // This test needs to be first.
+  it('should not blow up if unmounting nothing', () => {
+    $unmount();
+  });
+
+  it('should unmount component', () => {
+    let unmounted = false;
+
+    class Unmountable extends React.Component {
+      render() {
+        return null;
+      }
+
+      componentWillUnmount() {
+        unmounted = true;
+      }
+    }
+
+    $render(<Unmountable />);
+    $unmount();
+
+    expect(unmounted).toBeTruthy();
+  });
+
+  it('should recreate container after unmounting', () => {
+    const $container = $render(<span>bar</span>);
+    $unmount();
+    const $newContainer = $render(<span>baz</span>);
+
+    expect($container.text()).toHaveLength(0);
+    expect($newContainer.text()).toEqual('baz');
+  });
+
+  it('should cleanup after unmounting', () => {
+    let flushed = false;
+
+    const Foo = () => {
+      useEffect(() => () => {
+        flushed = true;
+      });
+
+      return null;
+    };
+
+    $render(<Foo />);
+    $unmount();
+
+    expect(flushed).toBeTruthy();
+  });
+});