Function assert_parse_eq 

pub fn assert_parse_eq<E: Debug>(
    parse_result: Result<Option<SyntaxNode>, E>,
    _input: &str,
    expected_sexp: &str,
    options: &SexpOptions,
)

Assert that parsing input yields a tree whose S-expression equals expected_sexp.

parse_result is typically parse(input) or parse_expression(input) returning Result<Option<SyntaxNode>, E>. On failure prints expected vs got S-expression.