/// Given a raw identifier (such as a table name, column name, etc.), format it
/// so that it may be safely interpolated into a SQL query.
pub fn escape_identifier(identifier: &str) -> String {
    // Escaping identifiers for Postgres is fairly easy, provided that the input is
    // already known to contain no invalid multi-byte sequences. Backslashes may
    // remain as-is, and embedded double quotes are escaped simply by doubling
    // them (`"` becomes `""`). Refer to the PQescapeInternal() function in
    // libpq (fe-exec.c) and Diesel's PgQueryBuilder::push_identifier().
    format!("\"{}\"", identifier.replace('"', "\"\""))
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn test_escape_identifier() {
        assert_eq!(escape_identifier("hello"), r#""hello""#);
        assert_eq!(escape_identifier("hello world"), r#""hello world""#);
        assert_eq!(
            escape_identifier(r#""hello" "world""#),
            r#""""hello"" ""world""""#
        );
    }
}