Add HeaderNarrowScreenOnlyGridCell tests

packages/react/src/Header/HeaderNarrowScreenOnlyGridCell.test.tsx

@@ -0,0 +1,49 @@
+import { render } from '@testing-library/react'
+import { createRef } from 'react'
+import { HeaderNarrowScreenOnlyGridCell } from './HeaderNarrowScreenOnlyGridCell'
+import '@testing-library/jest-dom'
+
+describe('HeaderNarrowScreenOnlyGridCell', () => {
+  it('renders', () => {
+    const { container } = render(<HeaderNarrowScreenOnlyGridCell />)
+
+    const component = container.querySelector(':only-child')
+
+    expect(component).toBeInTheDocument()
+    expect(component).toBeVisible()
+  })
+
+  it('renders a Grid.Cell', () => {
+    const { container } = render(<HeaderNarrowScreenOnlyGridCell />)
+
+    const component = container.querySelector(':only-child')
+
+    expect(component).toHaveClass('ams-grid__cell')
+  })
+
+  it('renders a design system BEM class name', () => {
+    const { container } = render(<HeaderNarrowScreenOnlyGridCell />)
+
+    const component = container.querySelector(':only-child')
+
+    expect(component).toHaveClass('ams-header__narrow-screen-only-grid-cell')
+  })
+
+  it('renders an additional class name', () => {
+    const { container } = render(<HeaderNarrowScreenOnlyGridCell className="extra" />)
+
+    const component = container.querySelector(':only-child')
+
+    expect(component).toHaveClass('ams-header__narrow-screen-only-grid-cell extra')
+  })
+
+  it('supports ForwardRef in React', () => {
+    const ref = createRef<HTMLDivElement>()
+
+    const { container } = render(<HeaderNarrowScreenOnlyGridCell ref={ref} />)
+
+    const component = container.querySelector(':only-child')
+
+    expect(ref.current).toBe(component)
+  })
+})