Then the optimized image should offer the "avif" format

Assert the first optimized image of the page does (or does not) offer an image format: gatsby-plugin-image lists one <source type="image/..."> per format in the formats option (avif, webp; auto is the main image).

Examples

Then the optimized image should offer the "avif" format
And the optimized image should offer the "webp" format
But the optimized image should not offer the "jpeg" format
Then optimized image should offer the "webp" format
And the optimized image should offer the "avif" format

Pattern

Then(/^(?:the )?optimized image should( not)* offer the "([^"]*)?" format$/, …)

Part of @webship-js/gatsby-steps (github.com/webship/gatsby-steps), a step pack for Webship-js 2.0.x.