test(SocialButton): complete GitHub icon testing

close #64

src/components/SocialButton/SocialButton.test.tsx

@@ -1,13 +1,35 @@
 import React from 'react';
 import renderer from 'react-test-renderer';
-
+import { render } from '@testing-library/react';
 import SocialButton from './SocialButton';
 
-describe('Header', () => {
-  it('renders correctly', () => {
+describe('SocialButton', () => {
+  test('render GitHub correctly (snapshot)', () => {
     const tree = renderer
       .create(<SocialButton type="github" url="https://github.com/" />)
       .toJSON();
+
     expect(tree).toMatchSnapshot();
   });
+
+  test('render GitHub with correct structure', () => {
+    const { getByRole } = render(
+      <SocialButton type="github" url="https://github.com/" />
+    );
+    const link = getByRole('link');
+    const icon = getByRole('img');
+
+    expect(link).toBeInTheDocument();
+    expect(icon).toBeInTheDocument();
+    expect(link).toContainElement(icon);
+  });
+
+  test('render GitHub with correct structure', () => {
+    const { getByRole } = render(
+      <SocialButton type="github" url="https://github.com/" />
+    );
+    const link = getByRole('link');
+
+    expect(link).toHaveAttribute('href', 'https://github.com/');
+  });
 });

src/components/SocialButton/__snapshots__/SocialButton.test.tsx.snap

@@ -1,13 +1,14 @@
 // Jest Snapshot v1, https://goo.gl/fbAQLP
 
-exports[`Header renders correctly 1`] = `
+exports[`SocialButton render GitHub correctly (snapshot) 1`] = `
 <a
   className="ant-btn ant-btn-link ant-btn-lg ant-btn-icon-only text-center text-light rounded-none "
   href="https://github.com/"
   onClick={[Function]}
+  role="link"
   style={
     Object {
-      "backgroundColor": undefined,
+      "backgroundColor": "",
     }
   }
 >