Acronyms

SLE

sle is STLedgerEntry or Serialized Ledger Entry.

env.le

// Note that bob still has a buy offer on the books.
BEAST_EXPECT(env.le(keylet::nftoffer(bobBuyOfferIndex)));

le is an annoying method name. I always read it as "less-than-or-equal". But it's supposed to mean "ledger entry". So we're verifying that bob's buy offer is still in the ledger. Here's the declaration of the method: https://github.com/XRPLF/rippled/blob/develop/src/test/jtx/Env.h#L430-L434