#[cfg(test)]
mod usage_test {
    use rt_write_lock::Reader;

    #[test]
    fn create_two_times() {
        let mut reader: Reader<u32> = Reader::default();
        let writer = reader.get_writer().unwrap();
        assert!(reader.get_writer().is_none());
        drop(writer);
        reader.get_writer().unwrap();
    }

    #[test]
    fn single_thread() {
        let mut reader: Reader<u32> = Reader::default();
        let mut writer = reader.get_writer().unwrap();

        let mut write = writer.write();
        assert!(reader.get_writer().is_none());
        let read = reader.try_read().unwrap();
        assert!(*read == 0);
        assert!(*write == 0);

        *write = 2;
        assert!(*read == 0);
        assert!(*write == 2);
        drop(write);

        let write = writer.write();
        assert!(*read == 0);
        assert!(*write == 2);
        drop(read);

        assert!(reader.try_read().is_none());
    }

    #[test]
    fn drop_reader_first() {
        let mut reader: Reader<u32> = Reader::default();
        let writer = reader.get_writer().unwrap();

        // drop order opposite of normal
        drop(reader);
        drop(writer);
    }

    #[test]
    #[should_panic]
    fn double_write() {
        let mut reader: Reader<u32> = Reader::default();
        let mut writer = reader.get_writer().unwrap();

        let write = writer.write();
        core::mem::forget(write);
        writer.write();
    }

    #[test]
    fn threads() {
        let mut reader: Reader<u32> = Reader::default();
        let mut writer = reader.get_writer().unwrap();

        std::thread::scope(|s| {
            let read = reader.try_read().unwrap();
            assert!(*read == 0);
            s.spawn(move || {
                let mut write = writer.write();
                *write = 15;
            });
            assert!(*read == 0);
            drop(read);
            let read = reader.try_read().unwrap();
            assert!(*read == 0 || *read == 15);
        });
        let read = reader.try_read().unwrap();
        assert!(*read == 15);
    }
}