Is your feature request related to a problem? Please describe.

The testing documentation is out of date, eg. suggests using pub serve.

Describe the solution you'd like

The documentation and potentially the testing tools to be updated. I plan to go through the sample when I get some time and try and update.

Describe alternatives you've considered

Maybe review the other test folders in samples/client/petstore/dart2/ at the same time and update together.

Additional context

https://dart.dev/tools/pub/obsolete