add test to ensure components are disposed (closes #17)

tests/hooks.test.js

@@ -0,0 +1,45 @@
+import React, {useRef} from 'react';
+import {useBootstrap} from '../src/lib/hooks';
+import {render} from '@testing-library/react';
+
+describe('use bootstrap hook', () => {
+  test('disposes component on unmount', () => {
+    const dispose = jest.fn();
+
+    /**
+     * Fake bootstrap component
+     */
+    class Component {
+      /**
+       * Mock bootstraps dispose, which calls our mock we can spy on
+       */
+      dispose() {
+        dispose();
+      }
+
+      /**
+       * Mock bootstraps getInstance
+       */
+      static getInstance() {
+        return null;
+      }
+    };
+
+    const events = new Map([]);
+    const config = {};
+
+    /**
+     * React component that uses the useBootstrap hook
+     */
+    function TestComponent() {
+      const ref = useRef();
+      useBootstrap(Component, config, undefined, ref, events);
+      return <span ref={ref}></span>;
+    }
+
+    const {unmount} = render(<TestComponent />);
+    unmount();
+
+    expect(dispose).toHaveBeenCalledTimes(1);
+  });
+});