With such integration tests, you can easily and reliably get the
new SkSLs when the app code changes, or when Flutter upgrades.
Such tests can also be used to verify the performance change
before and after the SkSL warm-up. Even better, you can put
those tests into a CI (continuous integration) system so the
SkSLs are generated and tested automatically over the lifetime of an app.

Note:
  The integration_test package is now the recommended way to write integration
  tests. See the Integration testing page
  for details.

Take the original version of Flutter Gallery as an example.
The CI system is set up to generate SkSLs for every Flutter commit,
and verifies the performance, in the transitions_perf_test.dart test.
For more details, see the flutter_gallery_sksl_warmup__transition_perf
and flutter_gallery_sksl_warmup__transition_perf_e2e_ios32 tasks.