Testing Rich Text Interactions in JSON Editors

JSON (JavaScript Object Notation) is a ubiquitous format for structured data exchange. While primarily designed for simple values like strings, numbers, booleans, arrays, and objects, real-world applications often require storing content with formatting – like bold text, lists, or links. This is whererich text fields within JSON editors come into play. They allow users to author formatted content that gets stored as a string value within the JSON structure.

However, integrating and correctly handling rich text introduces significant complexity compared to simple plain text fields. Thorough testing is crucial to ensure data integrity, a smooth user experience, and prevention of potential issues. This article explores the unique challenges and effective strategies for testing rich text interactions in JSON editors.

The Core Challenge: JSON vs. Rich Text

JSON is fundamentally a plain text format. Rich text, on the other hand, requires a way to represent formatting. When rich text is stored in a JSON value, it must be encoded into a string format. Common approaches include:

• Storing HTML: The rich text is converted into an HTML string (e.g.,<p>Hello, <strong>world!</strong></p>). This is common as HTML is the native format for web rendering.
• Storing Markdown: The rich text is converted into a Markdown string (e.g.,Hello, **world**!). This is often more human-readable but requires a separate rendering step.
• Storing Custom JSON Formats: Some editors use their own JSON structure to represent the rich text document (e.g., Lexical, Slate, Prosemirror). This requires careful handling of serialization and deserialization.

Regardless of the chosen format, the core testing challenge is ensuring the round trip: rich text authored in the editor ➔ correctly encoded into the JSON string ➔ JSON string parsed and correctly rendered back as rich text in the editor or elsewhere.

Levels of Testing

Testing rich text in JSON editors can be approached at different levels, each providing valuable coverage:

• Unit Tests: Focus on the smaller parts. Test the rich text editor component in isolation to ensure basic functionality (typing, formatting, undo/redo) works. Test the serialization/deserialization logic that converts rich text structures to/from JSON strings.
• Integration Tests: Test the interaction between the rich text editor component and the larger JSON editor component. Simulate entering rich text in a specific field and verify that the correct string representation appears in the underlying JSON state or output. Test loading JSON with pre-existing rich text strings and verify they render correctly in the editor field.
• End-to-End (E2E) Tests: Simulate real user workflows. Open the JSON editor, navigate to a rich text field, enter formatted text, save the JSON, reload the JSON, and verify the formatted text is displayed correctly. These tests catch issues that might only appear when all parts of the system are connected (editor, JSON parser, state management, rendering).

Key Areas and Test Cases

Here are specific scenarios and types of interactions to focus on during testing:

Input and Formatting Integrity

• Basic Formatting: Test applying bold, italics, underline, strikethrough. Verify the formatting appears in the editor and the correct markup (e.g., <strong> or **) is present in the generated JSON string value.
• Lists: Test ordered lists (<ol>) and unordered lists (<ul>). Test nested lists. Verify list items and nesting are correctly represented in the output string.
• Links: Test inserting links with different URLs (absolute, relative) and link text. Verify the <a href="..."> tag or Markdown equivalent is correct in the string. Test malformed URLs or special characters in URLs.
• Headings/Blockquotes: If supported, test different heading levels (<h1> to <h6>) and blockquotes (<blockquote>).
• Combinations and Nesting: Test applying multiple formats to the same text (e.g., bold and italics). Test nesting elements (e.g., a link inside a bolded list item: <li><strong><a href="...">Link</a></strong></li>).

Interaction with JSON Structure

• Editing within different JSON types: Test editing a rich text field that is a value in an object, an element in an array, or nested within multiple layers of objects/arrays. Example JSON:

  {
    "article": {
      "sections": [
        {
          "title": "Introduction",
          "content": "<p>This is &lt;strong&gt;rich&lt;/strong&gt; intro text.</p>" // <-- Rich text field
        },
        {
          "title": "Details",
          "paragraphs": [
            "<p>First &lt;em&gt;paragraph&lt;/em&gt;.</p>", // <-- Rich text field
            "<p>Second paragraph with a <a href='...'>link</a>.</p>" // <-- Rich text field
          ]
        }
      ]
    }
  }

  Verify that editing the rich text string in one field does not corrupt the JSON structure or other fields.
• Special Characters and Escaping: JSON strings have specific escaping rules (e.g.," must be \", \ must be \\). Rich text content (especially HTML or Markdown) frequently contains quotes and backslashes. Test that the editor correctly escapes these characters when converting the rich text content into the JSON string value. For example, entering the text He said "Hello!" might need to become "He said \\"Hello!\\""within the JSON string value, depending on the rich text format encoding.

Editor Functionality & Edge Cases

• Copy/Paste: Test copying formatted text from external sources (web pages, Word documents) and pasting it into the rich text field. Test copying formatted text *from* the rich text field. Verify formatting is retained appropriately or correctly stripped/sanitized according to expected behavior.
• Undo/Redo: Test that undo/redo works reliably for various formatting changes and text edits within the rich text field.
• Empty States: Test the behavior when the rich text field is empty. What value is stored in the JSON (e.g., "", null, or a minimal representation like "<p></p>")? Test loading JSON where the rich text field is empty.
• Large Content: Test entering and editing very long strings of rich text to check performance and potential memory issues.
• Invalid Input/Sanitization: If storing HTML, test entering malicious or invalid HTML (e.g., <script>alert('XSS')</script>). The editor or rendering logic must properly sanitize this input to prevent Cross-Site Scripting (XSS) vulnerabilities. Verify that dangerous tags/attributes are stripped or encoded.
• Browser Compatibility: Rich text editors often rely heavily on browser APIs (likecontenteditable). Test the editor and its interactions across different browsers.

Loading and Saving

• Loading Valid JSON: Load JSON documents that contain rich text fields with various formatting. Verify that the content is displayed correctly in the rich text editor fields.
• Loading Invalid Rich Text: Load JSON where a string value intended for a rich text field contains malformed markup (e.g., unclosed tags). How does the editor handle this? Does it crash, or does it render gracefully, perhaps showing the raw markup or attempting correction?
• Saving Modified Content: Load JSON, make edits in a rich text field, then save. Load the newly saved JSON and verify the changes are persisted and rendered correctly.

Tools and Technologies

Effective testing of rich text in JSON editors often involves leveraging specific tools:

• Rich Text Editor Libraries: Testing will depend on the library used (e.g., Lexical, Slate, Tiptap, Quill, TinyMCE, CKEditor). Understand the library's API for programmatic interaction and content manipulation in tests.
• Testing Frameworks: Jest or Vitest for unit tests. React Testing Library for component integration tests. Cypress or Playwright for E2E tests to automate browser interactions.
• Snapshot Testing: For unit tests on serialization/deserialization, snapshot testing can be useful to quickly check if the output string format for a given rich text structure changes unexpectedly.
• JSON Schema Validation: While not directly testing rich text *interactions*, ensuring the overall JSON structure remains valid after rich text edits is important and can be checked with schema validation libraries.

Conclusion

Adding rich text capabilities to a JSON editor significantly enhances its power but introduces a layer of complexity that demands rigorous testing. By understanding how rich text is encoded within JSON strings and focusing on testing input/output integrity, editor functionality, interactions with the JSON structure, and edge cases, developers can build more robust and reliable JSON editors. Leveraging appropriate testing tools and approaching testing at unit, integration, and E2E levels will help ensure a seamless experience for users authoring formatted content within structured JSON data.