verify-email-snapshots

Render email templates and compare HTML output against .verified.html baselines.

1.1k|101|Updated Nov 12, 2025

Search Tags:#HTML #email #dotnet #unit-testing #verify #MJML #snapshot-testing

Ready to run

npx skills add https://github.com/Aaronontheweb/dotnet-skills --skill verify-email-snapshots

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Please help me install this Agent Skill.
Skill: verify-email-snapshots
Source: https://github.com/Aaronontheweb/dotnet-skills/tree/main/skills/verify-email-snapshots
Command: npx skills add https://github.com/Aaronontheweb/dotnet-skills --skill verify-email-snapshots

SYSTEM DOCUMENTATION & REQUIREMENTS

What problem does it solve?

This Skill enables automated snapshot testing of email templates to catch regressions between renders and approved baselines. It targets MJML and HTML-based emails, ensuring consistent rendering as templates evolve.

Core Features & Use Cases

Snapshot rendering: render email templates and capture HTML for regression checks.
Baseline verification: compare rendered output against verified baselines and fail on diffs.
MJML & renderer support: works with MJML templates and any HTML renderer used in your project.

Quick Start

Create a unit test that renders an email template using a renderer (for example IMjmlTemplateRenderer) and asserts the resulting HTML with Verify. The first run generates a .verified.html baseline.

Frequently Asked Questions about verify-email-snapshots

High-intent search queries and answers about installing and using this skill.

FAQPage Schema

How do I catch email template regressions in dotnet unit tests?▼

You can catch email template regressions by using snapshot testing to render MJML or HTML templates and compare the output against an approved .verified.html baseline, failing the unit test on any differences.

What is snapshot testing for MJML and HTML emails?▼

Snapshot testing for MJML and HTML emails is an automated technique that captures rendered template output into a baseline file, comparing subsequent renders against it to detect unexpected visual or structural changes.

How do I set up email snapshot testing with Verify.Xunit?▼

Set up email snapshot testing with Verify.Xunit by creating a unit test that renders your template using a test harness like IMjmlTemplateRenderer, then asserting the resulting HTML with Verify to generate the initial baseline.

Do I need a specific renderer to test MJML templates with Verify?▼

Yes, you need a test harness capable of rendering templates, such as an IMjmlTemplateRenderer, to generate the HTML output that Verify.Xunit compares against the approved baseline.

Can I use this snapshot testing approach for plain HTML emails?▼

Yes, this approach supports HTML-based emails across common templates, rendering the HTML output and validating it against .verified.html baselines to ensure consistent rendering as templates evolve.