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Validating MDX Parser Error Handling in GatsbyJS

This test suite validates the parser functionality in Gatsby Recipes, focusing on syntax error detection and validation. It ensures proper handling of MDX content and file component validation within recipe files.

Test Coverage Overview

The test coverage focuses on validating parser error handling for Gatsby Recipes.

Key areas tested include:

MDX syntax validation
File component parsing
Error line number detection
Error type classification

The suite specifically tests edge cases around malformed File components and incomplete MDX markup.

Implementation Analysis

The testing approach implements unit tests for the validate function using Jest framework. It utilizes fixture-based testing patterns with sample MDX content containing intentionally malformed syntax.

The implementation employs skip annotation (test.skip) to handle pending MDX v2 compatibility updates.

Technical Details

Testing tools and setup:

Jest as the testing framework
Custom validate module for parsing
MDX parsing functionality
Test fixtures with sample MDX content
Error object validation for line numbers and error types

Best Practices Demonstrated

The test suite demonstrates several testing best practices including isolated unit testing, clear test descriptions, and proper error validation.

Notable practices include:

Descriptive test naming
Fixture-based test data
Explicit error property validation
Forward-compatible test skipping
Clear documentation of pending updates

gatsbyjs/gatsby

deprecated-packages/gatsby-recipes/src/parser/validate.test.js

            
const validate = require(`./validate`)

const fixture = `
# Hello, world!

---

<File path="here" content="there" />
<File path="here" content="there" /
`

// XXX: This needs to be updated for MDX v2, there error will be native
//      from the parser and we're currently swallowing it
test.skip(`validate returns a syntax error`, () => {
  const result = validate(fixture)

  expect(result.line).toEqual(7)
  expect(result.errorType).toEqual(`parse`)
})