Testing functional UIs - Hayleigh Thompson | Lambda Days

[CodeSync]

Testing functional UIs - Hayleigh Thompson | Lambda Days 2025

Testing functional UIs - Hayleigh Thompson | Lambda Days 2025

This talk was recorded at Lambda Days in June 2025. If you’re curious about our upcoming event, check https://lambdadays.org

Testing functional UIs

The state of frontend testing is all a bit rubbish. Often we default to end-to-end tests and visual snapshots - if we even write tests at all - that are slow and error prone. But we do functional programming, can’t we do better?!

In this talk we’ll break down and better understand what exactly it is we’re trying to test when testing user interfaces before taking a look at how the properties of functional UI frameworks like Elm and Lustre can make writing tests easier, faster, and more robust.

Crucially, we’ll walk away with a toolkit of testing approaches we can reach for before we need to pull out Cypress and grind our CI to a halt!

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