Added unit test for TodoItem component

Author: gsaini

src/components/TodoItem/TodoItem.spec.tsx

@@ -0,0 +1,23 @@
+import { fireEvent } from '@testing-library/react';
+import React from 'react';
+import { render } from '../../test-utils';
+import { TodoItem } from './TodoItem';
+
+describe('Todos components', () => {
+    const todo = { id: "1", title: "lorem ipsum", completed: false };
+
+    it('should render snapshot', async () => {
+        const { container } = await render(<TodoItem todo={todo} onChange={jest.fn()} />);
+
+        expect(container).toMatchSnapshot();
+    });
+
+    it('should toggle status', async () => {
+        const onChangeMock = jest.fn();
+        const { getByLabelText } = await render(<TodoItem todo={todo} onChange={onChangeMock} />);
+
+        fireEvent.click(getByLabelText(todo.title));
+
+        expect(onChangeMock).toHaveBeenCalledWith({ id: todo.id, completed: true });
+    });
+});

src/components/TodoItem/__snapshots__/TodoItem.spec.tsx.snap

@@ -0,0 +1,19 @@
+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`Todos components should render snapshot 1`] = `
+<div>
+  <div
+    class="Todo__item"
+  >
+    <label
+      for="1-checkbox"
+    >
+      lorem ipsum
+    </label>
+    <input
+      id="1-checkbox"
+      type="checkbox"
+    />
+  </div>
+</div>
+`;

src/test-utils/Provider.tsx

@@ -6,9 +6,9 @@ import { cache } from '../apollo';
 
 const customRender = async (
     childComponent: JSX.Element,
-    options: MockedProviderProps
+    options?: MockedProviderProps
 ): Promise<RenderResult> => {
-    const { mocks, resolvers = {} } = options;
+    const { mocks = [], resolvers = {} } = options || {};
     const wrapper = render(<MockedProvider
         mocks={mocks}
         resolvers={resolvers}