Verify Email Snapshots

What it does

This skill enables AI agents to verify email snapshot accuracy against original rendered content. It's designed for testing email templates, particularly when using MJML, and helps identify discrepancies or unintended changes that might occur during rendering or template updates. The skill uses snapshot testing techniques to capture the rendered HTML and compare it against a baseline, flagging any unexpected differences.

When to use it

• Testing email template rendering for regressions (ensuring new code doesn't break existing functionality).
• Validating MJML templates compile to expected HTML output.
• Reviewing email changes during code review by providing visual diffs of rendered HTML.
• Ensuring variable substitution within email templates works correctly.

Key capabilities

• Captures rendered HTML as a snapshot for comparison.
• Identifies discrepancies between the current and baseline HTML rendering.
• Provides visual diffs to highlight changes in rendered output.
• Supports integration with testing frameworks like Xunit, NUnit, and MSTest.

Example prompts

• "Run an email template verification test for the 'UserSignupInvitation' template."
• "Show me the diff between the current rendering of the email snapshot and the baseline."
• "Verify that variable substitution is working correctly in the email template."

Tips & gotchas

• Requires installation of the Verify.Xunit (or equivalent for other testing frameworks) NuGet package.
• The first time a test is run, it creates a .verified.html file containing the initial snapshot. Subsequent runs compare against this baseline.