test: improve coverage

components/Header/__test__/Header.test.tsx

@@ -0,0 +1,10 @@
+import { render } from '@testing-library/react'
+
+import { Header } from '..'
+
+describe('<Header />', () => {
+  it('should render', async () => {
+    const { getByText } = render(<Header />)
+    expect(getByText('Divlo')).toBeInTheDocument()
+  })
+})