syntax_data: {"ast_node_type":"other","tokens":[{"end":61,"kind":"keyword","start":0,"text":"assert_eq!(sf.lookup_line(RelativeBytePos(14)),"}]}
source_snippet:     assert_eq!(sf.lookup_line(RelativeBytePos(14)), Some(1));
context_before:     assert_eq!(sf.lookup_line(RelativeBytePos(13)), Some(0));
context_after:     assert_eq!(sf.lookup_line(RelativeBytePos(15)), Some(1));