metamask-extension/docs/generating-fixture-data.md

Generating fixture data

Fixture data can be generated by following these steps:

1. Load the unpacked extension in development or test mode
2. Inspecting the background context of the extension
3. Call stateHooks.metamaskGetState, then call copy on the results

You can then paste the contents directly in your fixture file.

copy(await stateHooks.metamaskGetState())