test: Add tests for Modal has-body class

react/Modal/index.spec.jsx

@@ -0,0 +1,73 @@
+import React from 'react'
+import { act } from 'react-dom/test-utils'
+import { useState } from 'react'
+import { mount } from 'enzyme'
+import Modal, { BODY_CLASS } from './index'
+
+describe('Modal', () => {
+  const Example = () => {
+    const [showModal, setShowModal] = useState(false)
+    const [showModal2, setShowModal2] = useState(false)
+    return (
+      <div>
+        {showModal ? <Modal title="example 1">1</Modal> : null}
+        {showModal2 ? <Modal title="example 2">2</Modal> : null}
+        <button onClick={() => setShowModal(true)} />
+        <button onClick={() => setShowModal2(true)} />
+        <button onClick={() => setShowModal2(false)} />
+        <button onClick={() => setShowModal(false)} />
+      </div>
+    )
+  }
+
+  const clickNthButton = (root, n) =>
+    root
+      .find('button')
+      .at(n)
+      .props()
+      .onClick()
+
+  const mountFirstModal = root => clickNthButton(root, 0)
+  const mountSecondModal = root => clickNthButton(root, 1)
+  const unmountSecondModal = root => clickNthButton(root, 2)
+  const unmountFirstModal = root => clickNthButton(root, 3)
+
+  const hasModalBodyClass = () => document.body.classList.contains(BODY_CLASS)
+
+  afterEach(() => {
+    document.body.classList.remove(BODY_CLASS)
+  })
+
+  it('should apply a class to the body when mounted', () => {
+    const root = mount(<Example />)
+    expect(hasModalBodyClass()).toBe(false)
+    act(() => {
+      mountFirstModal(root)
+    })
+    expect(hasModalBodyClass()).toBe(true)
+    act(() => {
+      unmountFirstModal(root)
+    })
+    expect(hasModalBodyClass()).toBe(false)
+  })
+
+  it('should not remove the class if two modals were mounted and the second one is removed', () => {
+    const root = mount(<Example />)
+    expect(hasModalBodyClass()).toBe(false)
+    act(() => {
+      mountFirstModal(root)
+    })
+    expect(hasModalBodyClass()).toBe(true)
+    act(() => {
+      mountSecondModal(root)
+    })
+    act(() => {
+      unmountSecondModal(root)
+    })
+    expect(hasModalBodyClass()).toBe(true)
+    act(() => {
+      unmountFirstModal(root)
+    })
+    expect(hasModalBodyClass()).toBe(false)
+  })
+})