improve the hardbreak demo and add tests

docs/src/demos/Extensions/HardBreak/index.spec.js

@@ -1,5 +1,30 @@
 context('/api/extensions/hard-break', () => {
   beforeEach(() => {
     cy.visit('/api/extensions/hard-break')
+
+    cy.get('.ProseMirror').window().then(window => {
+      const { editor } = window
+      editor.setContent('<p>Example Text</p>')
+    })
+  })
+
+  describe('hard-break', () => {
+    it('the button should add a line break', () => {
+      cy.get('.ProseMirror br').should('not.exist')
+      cy.get('.demo__preview button:first').click({ force: true })
+      cy.get('.ProseMirror br').should('exist')
+    })
+
+    it('the default keyboard shortcut should add a line break', () => {
+      cy.get('.ProseMirror br').should('not.exist')
+      cy.get('.ProseMirror').type('{shift}{enter}', {force: true})
+      cy.get('.ProseMirror br').should('exist')
+    })
+
+    it('the alternative keyboard shortcut should add a line break', () => {
+      cy.get('.ProseMirror br').should('not.exist')
+      cy.get('.ProseMirror').type('{meta}{enter}', {force: true})
+      cy.get('.ProseMirror br').should('exist')
+    })
   })
 })

docs/src/demos/Extensions/HardBreak/index.vue

@@ -1,5 +1,9 @@
 <template>
   <div v-if="editor">
+    <button @click="editor.focus().hardBreak()">
+      hardBreak
+    </button>
+
     <editor-content :editor="editor" />
   </div>
 </template>