FUND and SELL flows

The SWAP feature refers to trading an amount of a FROM crypto against an amount of a TO crypto.

The FUND feature refers to sending an amount of a FROM crypto to an external account (for example, funding a debit card).

The SELL feature refers to trading an amount of a FROM crypto against a FIAT amount.

From the perspective of the library application, the FUND and SELL specificities are irrelevant and have no difference with the SWAP feature.
They only impact the APDUs exchanged between Ledger Live and the Exchange application.

In the test framework, this behavior is entirely handled by the ExchangeTestRunner.