bootPopup() in tests/support/popupBoot.js mocked three of the modules
that reach the network, but a boot onto the transaction screen still
asked Blockscout for its transaction, and a boot onto the confirmation
screen had src/shared/etherscanLabels.js look the recipient up on
Etherscan, both through the real fetch().
tests/persistedFieldContract.test.js boots onto both, so every run sent
those requests and logged their answers after its tests had finished.
bootPopup() now replaces fetch() with the throwing stub other test files
use, and cleanupPopup() puts it back. tests/popupBoot.test.js checks
that both requests reach the stub.
Model: opus-5-5
sneak