mod section {     mod header {        mod write_to {            use std::borrow::Cow;             use crate::parse::section;             fn header(name: &str, subsection: impl Into<Option<(&'static str, &'static str)>>) -> section::Header<'_> {                let name = section::Name(Cow::Borrowed(name.into()));                if let Some((separator, subsection_name)) = subsection.into() {                    section::Header {                        name,                        separator: Some(Cow::Borrowed(separator.into())),                        subsection_name: Some(Cow::Borrowed(subsection_name.into())),                    }                } else {                    section::Header {                        name,                        separator: None,                        subsection_name: None,                    }                }            }             #[test]            fn legacy_subsection_format_does_not_use_escapes() {                let invalid = header("invalid", Some((".", "\\ \"")));                assert_eq!(                    invalid.to_bstring(),                    "[invalid.\\ \"]",                    "no escaping happens for legacy subsections"                );                assert!(invalid.is_legacy());            }             #[test]            fn subsections_escape_two_characters_only() {                let invalid = header("invalid", Some((" ", "\\ \"\npost newline")));                assert_eq!(                    invalid.to_bstring(),                    "[invalid \"\\\\ \\\"\npost newline\"]",                    "newlines are actually invalid in subsection, but they are possible due to unvalidated instance creation"                );                assert!(!invalid.is_legacy());            }        }    }} pub(crate) mod util {    //! This module is only included for tests, and contains common unit test helper    //! functions.     use std::{borrow::Cow, convert::TryFrom};     use crate::parse::{section, Comment, Event};     pub fn into_events(events: Vec<Event<'_>>) -> section::Events<'_> {        events.into()    }     pub fn section_header(        name: &str,        subsection: impl Into<Option<(&'static str, &'static str)>>,    ) -> section::Header<'_> {        let name = section::Name::try_from(name).unwrap();        if let Some((separator, subsection_name)) = subsection.into() {            section::Header {                name,                separator: Some(Cow::Borrowed(separator.into())),                subsection_name: Some(Cow::Borrowed(subsection_name.into())),            }        } else {            section::Header {                name,                separator: None,                subsection_name: None,            }        }    }     pub(crate) fn name_event(name: &'static str) -> Event<'static> {        Event::SectionKey(section::Key(Cow::Borrowed(name.into())))    }     pub(crate) fn value_event(value: &'static str) -> Event<'static> {        Event::Value(Cow::Borrowed(value.into()))    }     pub(crate) fn value_not_done_event(value: &'static str) -> Event<'static> {        Event::ValueNotDone(Cow::Borrowed(value.into()))    }     pub(crate) fn value_done_event(value: &'static str) -> Event<'static> {        Event::ValueDone(Cow::Borrowed(value.into()))    }     pub(crate) fn newline_event() -> Event<'static> {        newline_custom_event("\n")    }     pub(crate) fn newline_custom_event(value: &'static str) -> Event<'static> {        Event::Newline(Cow::Borrowed(value.into()))    }     pub(crate) fn whitespace_event(value: &'static str) -> Event<'static> {        Event::Whitespace(Cow::Borrowed(value.into()))    }     pub(crate) fn comment_event(tag: char, msg: &'static str) -> Event<'static> {        Event::Comment(comment(tag, msg))    }     pub(crate) fn comment(comment_tag: char, comment: &'static str) -> Comment<'static> {        Comment {            tag: comment_tag as u8,            text: Cow::Borrowed(comment.into()),        }    }     pub(crate) const fn fully_consumed<T>(t: T) -> (&'static [u8], T) {        (&[], t)    }}