test(portable-text-editor): test the value normalization of style prop

Test that when editing a block without a style prop, the result will have
a default style prop.

packages/@sanity/portable-text-editor/src/utils/__tests__/valueNormalization.test.tsx

@@ -0,0 +1,76 @@
+/**
+ * @jest-environment ./test/setup/jsdom.jest.env.ts
+ */
+// eslint-disable-next-line import/no-unassigned-import
+import '@testing-library/jest-dom/extend-expect'
+import {act} from 'react-dom/test-utils'
+import {render} from '@testing-library/react'
+
+import React from 'react'
+import {PortableTextEditor} from '../../editor/PortableTextEditor'
+import {PortableTextEditorTester, type} from '../../editor/__tests__/PortableTextEditorTester'
+
+describe('values: normalization', () => {
+  it("accepts incoming value with blocks without a style or markDefs prop, but doesn't leave them without them when editing them", () => {
+    const editorRef: React.RefObject<PortableTextEditor> = React.createRef()
+    const initialValue = [
+      {
+        _key: '5fc57af23597',
+        _type: 'myTestBlockType',
+        children: [
+          {
+            _key: 'be1c67c6971a',
+            _type: 'span',
+            marks: [],
+            text: 'Hello',
+          },
+        ],
+        markDefs: [],
+      },
+    ]
+    const onChange = jest.fn()
+    act(() => {
+      render(
+        <PortableTextEditorTester
+          onChange={onChange}
+          ref={editorRef}
+          type={type}
+          value={initialValue}
+        />
+      )
+    })
+    if (!editorRef.current) {
+      throw new Error('No editor')
+    }
+    act(() => {
+      if (editorRef.current) {
+        PortableTextEditor.focus(editorRef.current)
+        PortableTextEditor.select(editorRef.current, {
+          focus: {path: [{_key: '5fc57af23597'}, 'children', {_key: 'be1c67c6971a'}], offset: 0},
+          anchor: {path: [{_key: '5fc57af23597'}, 'children', {_key: 'be1c67c6971a'}], offset: 5},
+        })
+      }
+    })
+    act(() => {
+      if (editorRef.current) {
+        PortableTextEditor.toggleMark(editorRef.current, 'strong')
+      }
+    })
+    expect(PortableTextEditor.getValue(editorRef.current)).toEqual([
+      {
+        _key: '5fc57af23597',
+        _type: 'myTestBlockType',
+        children: [
+          {
+            _key: 'be1c67c6971a',
+            _type: 'span',
+            marks: ['strong'],
+            text: 'Hello',
+          },
+        ],
+        markDefs: [],
+        style: 'normal',
+      },
+    ])
+  })
+})