fxa/docs/adr/0021-use-internjs-testing.md

Use existing InternJS for functional testing in settings v2

• Deciders: Vijay Budhram, Jody Heavener, Lauren Zugai
• Date: 2020-07-17

Context and Problem Statement

For over the past 5 years (at least), we have been using InternJS for our functional tests in the content-server. While this has worked well and caught several bugs, we should reevaluate it since we are migrating to react and have an opportunityto use newer/faster/better supported testing frameworks.

Decision Drivers

• Ease of writing tests
• Good community support
• Learning curve of settings V2 development

Decision Outcome

Use InternJS for functional testing in the settings v2 app, but also update the tests to support async/await. The biggest factor was not having to introduce another testing framework for developers to learn.

Considered Options

• Option A - Use InternJS and update to async/await
• Option B - Use NightmareJS
• Option C - Use WebDriverIO

Pros and Cons of the Options

Option A - Use InternJS and update to async/await

Pros:

• Active community
• Can reuse the testing patterns from content-server
• Lots of examples and helper functions to help write tests
• Developers won't have to context switch with testing frameworks

Cons:

• Still requires a learning curve to understand how things work and are structured
• It's kind of clunky, would be a lot of effort to go refactor all tests to async/await and could be better to just rewrite them with another library
• It's an older framework, a newer framework may offer greater support and features
• Our tests are a little flaky, can another framework help mitigate false failures from CI?

Option B - Use NightmareJS

Pros:

• Claims to be 2x faster than PhantomJS

Cons:

• Developers/QA will have to learn a new testing framework on top of all the other new frameworks introduced
• Is chromium based

Option C - Use WebDriverIO

Pros:

• Active community
• Used by other Mozilla services
• Simple API
• Solid documentation

Cons:

• Developers/QA will have to learn a new testing framework on top of all the other new frameworks introduced