#![deny(rust_2018_idioms)]
#![doc(
    html_logo_url = "https://storage.googleapis.com/fdo-gitlab-uploads/project/avatar/3213/zbus-logomark.png"
)]

//! This crate provides API for serialization/deserialization of data to/from [D-Bus] wire format.
//! This binary wire format is simple and very efficient and hence useful outside of D-Bus context
//! as well. A modified form of this format, [GVariant] is very commonly used for efficient storage
//! of arbitrary data and is also supported by this crate.
//!
//! Since version 2.0, the API is [serde]-based and hence you'll find it very intuitive if you're
//! already familiar with serde. If you're not familiar with serde, you may want to first read its
//! [tutorial] before learning further about this crate.
//!
//! Serialization and deserialization is achieved through the [toplevel functions]:
//!
//! ```rust
//! use std::collections::HashMap;
//! use byteorder::LE;
//! use zvariant::{from_slice, to_bytes};
//! use zvariant::EncodingContext as Context;
//!
//! // All serialization and deserialization API, needs a context.
//! let ctxt = Context::<LE>::new_dbus(0);
//! // You can also use the more efficient GVariant format:
//! // let ctxt = Context::<LE>::new_gvariant(0);
//!
//! // i16
//! let encoded = to_bytes(ctxt, &42i16).unwrap();
//! let decoded: i16 = from_slice(&encoded, ctxt).unwrap();
//! assert_eq!(decoded, 42);
//!
//! // strings
//! let encoded = to_bytes(ctxt, &"hello").unwrap();
//! let decoded: &str = from_slice(&encoded, ctxt).unwrap();
//! assert_eq!(decoded, "hello");
//!
//! // tuples
//! let t = ("hello", 42i32, true);
//! let encoded = to_bytes(ctxt, &t).unwrap();
//! let decoded: (&str, i32, bool) = from_slice(&encoded, ctxt).unwrap();
//! assert_eq!(decoded, t);
//!
//! // Vec
//! let v = vec!["hello", "world!"];
//! let encoded = to_bytes(ctxt, &v).unwrap();
//! let decoded: Vec<&str> = from_slice(&encoded, ctxt).unwrap();
//! assert_eq!(decoded, v);
//!
//! // Dictionary
//! let mut map: HashMap<i64, &str> = HashMap::new();
//! map.insert(1, "123");
//! map.insert(2, "456");
//! let encoded = to_bytes(ctxt, &map).unwrap();
//! let decoded: HashMap<i64, &str> = from_slice(&encoded, ctxt).unwrap();
//! assert_eq!(decoded[&1], "123");
//! assert_eq!(decoded[&2], "456");
//! ```
//!
//! Apart from the obvious requirement of [`EncodingContext`] instance by the main serialization and
//! deserialization API, the type being serialized or deserialized must also implement `Type`
//! trait in addition to [`Serialize`] or [`Deserialize`], respectively. Please refer to [`Type`
//! module documentation] for more details.
//!
//! Most of the [basic types] of D-Bus match 1-1 wit all the primitive Rust types. The only two
//! exceptions being, [`Signature`] and [`ObjectPath`], which are really just strings. These types
//! are covered by the [`Basic`] trait.
//!
//! Similarly, most of the [container types] also map nicely to the usual Rust types and
//! collections (as can be seen in the example code above). The only note worthy exception being
//! ARRAY type. As arrays in Rust are fixed-sized, serde treats them as tuples and so does this
//! crate. This means they are encoded as STRUCT type of D-Bus. If you need to serialize to, or
//! deserialize from a D-Bus array, you'll need to use a [slice] (array can easily be converted to a
//! slice), a [`Vec`] or an [`arrayvec::ArrayVec`].
//!
//! The generic D-Bus type, `VARIANT` is represented by `Value`, an enum that holds exactly one
//! value of any of the other types. Please refer to [`Value` module documentation] for examples.
//!
//! # no-std
//!
//! While `std` is currently a hard requirement, optional `no-std` support is planned in the future.
//! On the other hand, `noalloc` support is not planned as it will be extremely difficult to
//! accomplish. However, community contribution can change that. 😊
//!
//! # Optional features
//!
//! | Feature | Description |
//! | ---     | ----------- |
//! | arrayvec | Implement `Type` for [`arrayvec::ArrayVec`] and [`arrayvec::ArrayString`] |
//! | enumflags2 | Implement `Type` for [`struct@enumflags2::BitFlags<F>`] |
//!
//! # Portability
//!
//! zvariant is currently Unix-only and will fail to build on non-unix. This is hopefully a
//! temporary limitation.
//!
//! [D-Bus]: https://dbus.freedesktop.org/doc/dbus-specification.html
//! [GVariant]: https://developer.gnome.org/glib/stable/glib-GVariant.html
//! [serde]: https://crates.io/crates/serde
//! [tutorial]: https://serde.rs/
//! [toplevel functions]: #functions
//! [`EncodingContext`]: struct.EncodingContext.html
//! [`Serialize`]: https://docs.serde.rs/serde/trait.Serialize.html
//! [`Deserialize`]: https://docs.serde.rs/serde/de/trait.Deserialize.html
//! [`Type` module documentation]: trait.Type.html
//! [basic types]: https://dbus.freedesktop.org/doc/dbus-specification.html#basic-types
//! [`Signature`]: struct.Signature.html
//! [`ObjectPath`]: struct.ObjectPath.html
//! [`Basic`]: trait.Basic.html
//! [container types]: https://dbus.freedesktop.org/doc/dbus-specification.html#container-types
//! [slice]: https://doc.rust-lang.org/std/primitive.slice.html
//! [`Vec`]: https://doc.rust-lang.org/std/vec/struct.Vec.html
//! [`arrayvec::ArrayVec`]: https://docs.rs/arrayvec/0.5.1/arrayvec/struct.ArrayVec.html
//! [`arrayvec::ArrayString`]: https://docs.rs/arrayvec/0.5.1/arrayvec/struct.ArrayString.html
//! [`Value` module documentation]: enum.Value.html

#[macro_use]
mod utils;
pub use utils::*;

mod array;
pub use array::*;

mod basic;
pub use basic::*;

mod dict;
pub use dict::*;

mod encoding_context;
pub use encoding_context::*;

mod fd;
pub use fd::*;

mod object_path;
pub use crate::object_path::*;

mod ser;
pub use ser::*;

mod de;
pub use de::*;

pub mod dbus;
#[cfg(feature = "gvariant")]
pub mod gvariant;

mod signature;
pub use crate::signature::*;

mod str;
pub use crate::str::*;

mod structure;
pub use crate::structure::*;

#[cfg(feature = "gvariant")]
mod maybe;
#[cfg(feature = "gvariant")]
pub use crate::maybe::*;

mod value;
pub use value::*;

mod serialize_value;
pub use serialize_value::*;

mod deserialize_value;
pub use deserialize_value::*;

mod error;
pub use error::*;

#[macro_use]
mod r#type;
pub use r#type::*;

mod from_value;
pub use from_value::*;

mod into_value;
pub use into_value::*;

mod owned_value;
pub use owned_value::*;

#[cfg(feature = "gvariant")]
mod framing_offset_size;
#[cfg(feature = "gvariant")]
mod framing_offsets;
mod signature_parser;

// FIXME: Re-export derive macros from the crate root with the next breaking-change release.
pub mod derive {
    pub use zvariant_derive::{DeserializeDict, SerializeDict, Type, TypeDict};
}

// Required for the macros to function within this crate.
extern crate self as zvariant;

// Macro support module, not part of the public API.
#[doc(hidden)]
pub mod export {
    pub use serde;
}

#[cfg(test)]
mod tests {
    use std::{
        collections::HashMap,
        convert::{TryFrom, TryInto},
    };

    #[cfg(feature = "arrayvec")]
    use arrayvec::{ArrayString, ArrayVec};
    use byteorder::{self, ByteOrder, BE, LE};
    #[cfg(feature = "arrayvec")]
    use std::str::FromStr;

    #[cfg(feature = "gvariant")]
    use glib::{Bytes, FromVariant, Variant};
    use serde::{Deserialize, Serialize};

    use zvariant_derive::{DeserializeDict, SerializeDict, Type, TypeDict};

    use crate::{
        from_slice, from_slice_fds, from_slice_for_signature, to_bytes, to_bytes_fds,
        to_bytes_for_signature,
    };

    use crate::{
        Array, Basic, DeserializeValue, Dict, EncodingContext as Context, EncodingFormat, Error,
        Fd, ObjectPath, Result, SerializeValue, Signature, Str, Structure, Type, Value,
    };

    // Test through both generic and specific API (wrt byte order)
    macro_rules! basic_type_test {
        ($trait:ty, $format:ident, $test_value:expr, $expected_len:expr, $expected_ty:ty, $align:literal) => {{
            // Lie that we're starting at byte 1 in the overall message to test padding
            let ctxt = Context::<$trait>::new(EncodingFormat::$format, 1);
            let (encoded, fds) = to_bytes_fds(ctxt, &$test_value).unwrap();
            let padding = crate::padding_for_n_bytes(1, $align);
            assert_eq!(
                encoded.len(),
                $expected_len + padding,
                "invalid encoding using `to_bytes`"
            );
            let decoded: $expected_ty = from_slice_fds(&encoded, Some(&fds), ctxt).unwrap();
            assert!(
                decoded == $test_value,
                "invalid decoding using `from_slice`"
            );

            // Now encode w/o padding
            let ctxt = Context::<$trait>::new(EncodingFormat::$format, 0);
            let (encoded, _) = to_bytes_fds(ctxt, &$test_value).unwrap();
            assert_eq!(
                encoded.len(),
                $expected_len,
                "invalid encoding using `to_bytes`"
            );

            encoded
        }};
        ($trait:ty, $format:ident, $test_value:expr, $expected_len:expr, $expected_ty:ty, $align:literal, $kind:ident, $expected_value_len:expr) => {{
            let encoded = basic_type_test!(
                $trait,
                $format,
                $test_value,
                $expected_len,
                $expected_ty,
                $align
            );

            // As Value
            let v: Value<'_> = $test_value.into();
            assert_eq!(v.value_signature(), <$expected_ty>::SIGNATURE_STR);
            assert_eq!(v, Value::$kind($test_value));
            value_test!(LE, $format, v, $expected_value_len);

            let v: $expected_ty = v.try_into().unwrap();
            assert_eq!(v, $test_value);

            encoded
        }};
    }

    macro_rules! value_test {
        ($trait:ty, $format:ident, $test_value:expr, $expected_len:expr) => {{
            let ctxt = Context::<$trait>::new(EncodingFormat::$format, 0);
            let (encoded, fds) = to_bytes_fds(ctxt, &$test_value).unwrap();
            assert_eq!(
                encoded.len(),
                $expected_len,
                "invalid encoding using `to_bytes`"
            );
            let decoded: Value<'_> = from_slice_fds(&encoded, Some(&fds), ctxt).unwrap();
            assert!(
                decoded == $test_value,
                "invalid decoding using `from_slice`"
            );

            encoded
        }};
    }

    #[cfg(feature = "gvariant")]
    fn decode_with_gvariant<B, T>(encoded: B) -> T
    where
        B: AsRef<[u8]> + Send + 'static,
        T: glib::variant::FromVariant,
    {
        let bytes = Bytes::from_owned(encoded);
        let gv = Variant::from_bytes::<T>(&bytes);
        gv.get::<T>().unwrap()
    }

    // All fixed size types have the same encoding in DBus and GVariant formats.
    //
    // NB: Value (i-e VARIANT type) isn't a fixed size type.

    #[test]
    fn u8_value() {
        let encoded = basic_type_test!(LE, DBus, 77_u8, 1, u8, 1, U8, 4);
        assert_eq!(encoded.len(), 1);
        #[cfg(feature = "gvariant")]
        {
            assert_eq!(decode_with_gvariant::<_, u8>(encoded), 77u8);
            basic_type_test!(LE, GVariant, 77_u8, 1, u8, 1, U8, 3);
        }
    }

    #[test]
    fn i8_value() {
        basic_type_test!(LE, DBus, 77_i8, 2, i8, 2);
        #[cfg(feature = "gvariant")]
        basic_type_test!(LE, GVariant, 77_i8, 2, i8, 2);
    }

    #[test]
    fn fd_value() {
        basic_type_test!(LE, DBus, Fd::from(42), 4, Fd, 4, Fd, 8);
        #[cfg(feature = "gvariant")]
        basic_type_test!(LE, GVariant, Fd::from(42), 4, Fd, 4, Fd, 6);
    }

    #[test]
    fn u16_value() {
        let encoded = basic_type_test!(BE, DBus, 0xABBA_u16, 2, u16, 2, U16, 6);
        assert_eq!(encoded.len(), 2);
        #[cfg(feature = "gvariant")]
        {
            assert_eq!(decode_with_gvariant::<_, u16>(encoded), 0xBAAB_u16);
            basic_type_test!(BE, GVariant, 0xABBA_u16, 2, u16, 2, U16, 4);
        }
    }

    #[test]
    fn i16_value() {
        let encoded = basic_type_test!(BE, DBus, -0xAB0_i16, 2, i16, 2, I16, 6);
        assert_eq!(LE::read_i16(&encoded), 0x50F5_i16);
        #[cfg(feature = "gvariant")]
        {
            assert_eq!(decode_with_gvariant::<_, i16>(encoded), 0x50F5_i16);
            basic_type_test!(BE, GVariant, -0xAB0_i16, 2, i16, 2, I16, 4);
        }
    }

    #[test]
    fn u32_value() {
        let encoded = basic_type_test!(BE, DBus, 0xABBA_ABBA_u32, 4, u32, 4, U32, 8);
        assert_eq!(encoded.len(), 4);
        #[cfg(feature = "gvariant")]
        {
            assert_eq!(decode_with_gvariant::<_, u32>(encoded), 0xBAAB_BAAB_u32);
            basic_type_test!(BE, GVariant, 0xABBA_ABBA_u32, 4, u32, 4, U32, 6);
        }
    }

    #[test]
    fn i32_value() {
        let encoded = basic_type_test!(BE, DBus, -0xABBA_AB0_i32, 4, i32, 4, I32, 8);
        assert_eq!(LE::read_i32(&encoded), 0x5055_44F5_i32);
        #[cfg(feature = "gvariant")]
        {
            assert_eq!(decode_with_gvariant::<_, i32>(encoded), 0x5055_44F5_i32);
            basic_type_test!(BE, GVariant, -0xABBA_AB0_i32, 4, i32, 4, I32, 6);
        }
    }

    // u64 is covered by `value_value` test below

    #[test]
    fn i64_value() {
        let encoded = basic_type_test!(BE, DBus, -0xABBA_ABBA_ABBA_AB0_i64, 8, i64, 8, I64, 16);
        assert_eq!(LE::read_i64(&encoded), 0x5055_4455_4455_44F5_i64);
        #[cfg(feature = "gvariant")]
        {
            assert_eq!(
                decode_with_gvariant::<_, i64>(encoded),
                0x5055_4455_4455_44F5_i64
            );
            basic_type_test!(BE, GVariant, -0xABBA_ABBA_ABBA_AB0_i64, 8, i64, 8, I64, 10);
        }
    }

    #[test]
    fn f64_value() {
        let encoded = basic_type_test!(BE, DBus, 99999.99999_f64, 8, f64, 8, F64, 16);
        assert_eq!(LE::read_f64(&encoded), -5759340900185448e-143);
        #[cfg(feature = "gvariant")]
        {
            assert_eq!(
                decode_with_gvariant::<_, f64>(encoded),
                -5759340900185448e-143
            );
            basic_type_test!(BE, GVariant, 99999.99999_f64, 8, f64, 8, F64, 10);
        }
    }

    #[test]
    fn str_value() {
        let string = String::from("hello world");
        basic_type_test!(LE, DBus, string, 16, String, 4);
        basic_type_test!(LE, DBus, string, 16, &str, 4);

        // GVariant format now
        #[cfg(feature = "gvariant")]
        {
            let encoded = basic_type_test!(LE, GVariant, string, 12, String, 1);
            assert_eq!(decode_with_gvariant::<_, String>(encoded), "hello world");
        }

        let string = "hello world";
        basic_type_test!(LE, DBus, string, 16, &str, 4);
        basic_type_test!(LE, DBus, string, 16, String, 4);

        // As Value
        let v: Value<'_> = string.into();
        assert_eq!(v.value_signature(), "s");
        assert_eq!(v, Value::new("hello world"));
        value_test!(LE, DBus, v, 20);
        #[cfg(feature = "gvariant")]
        {
            let encoded = value_test!(LE, GVariant, v, 14);

            // Check encoding against GLib
            let bytes = Bytes::from_owned(encoded);
            let gv = Variant::from_bytes::<Variant>(&bytes);
            let variant = gv.get_variant().unwrap();
            assert_eq!(variant.get_str().unwrap(), "hello world");
        }

        let v: String = v.try_into().unwrap();
        assert_eq!(v, "hello world");
        let v: String = v.try_into().unwrap();
        assert_eq!(v, "hello world");

        // Characters are treated as strings
        basic_type_test!(LE, DBus, 'c', 6, char, 4);
        #[cfg(feature = "gvariant")]
        basic_type_test!(LE, GVariant, 'c', 2, char, 1);

        // As Value
        let v: Value<'_> = "c".into();
        assert_eq!(v.value_signature(), "s");
        let ctxt = Context::new_dbus(0);
        let encoded = to_bytes::<LE, _>(ctxt, &v).unwrap();
        assert_eq!(encoded.len(), 10);
        let v = from_slice::<LE, Value<'_>>(&encoded, ctxt).unwrap();
        assert_eq!(v, Value::new("c"));
    }

    #[cfg(feature = "arrayvec")]
    #[test]
    fn array_string_value() {
        let s = ArrayString::<[_; 32]>::from_str("hello world!").unwrap();
        let ctxt = Context::<LE>::new_dbus(0);
        let encoded = to_bytes(ctxt, &s).unwrap();
        assert_eq!(encoded.len(), 17);
        let decoded: ArrayString<[_; 32]> = from_slice(&encoded, ctxt).unwrap();
        assert_eq!(&decoded, "hello world!");
    }

    #[test]
    fn signature_value() {
        let sig = Signature::try_from("yys").unwrap();
        basic_type_test!(LE, DBus, sig, 5, Signature<'_>, 1);

        #[cfg(feature = "gvariant")]
        {
            let encoded = basic_type_test!(LE, GVariant, sig, 4, Signature<'_>, 1);
            assert_eq!(decode_with_gvariant::<_, String>(encoded), "yys");
        }

        // As Value
        let v: Value<'_> = sig.into();
        assert_eq!(v.value_signature(), "g");
        let encoded = value_test!(LE, DBus, v, 8);
        let ctxt = Context::new_dbus(0);
        let v = from_slice::<LE, Value<'_>>(&encoded, ctxt).unwrap();
        assert_eq!(v, Value::Signature(Signature::try_from("yys").unwrap()));

        // GVariant format now
        #[cfg(feature = "gvariant")]
        {
            let encoded = value_test!(LE, GVariant, v, 6);
            let ctxt = Context::new_gvariant(0);
            let v = from_slice::<LE, Value<'_>>(&encoded, ctxt).unwrap();
            assert_eq!(v, Value::Signature(Signature::try_from("yys").unwrap()));
        }
    }

    #[test]
    fn object_path_value() {
        let o = ObjectPath::try_from("/hello/world").unwrap();
        basic_type_test!(LE, DBus, o, 17, ObjectPath<'_>, 4);

        #[cfg(feature = "gvariant")]
        {
            let encoded = basic_type_test!(LE, GVariant, o, 13, ObjectPath<'_>, 1);
            assert_eq!(decode_with_gvariant::<_, String>(encoded), "/hello/world");
        }

        // As Value
        let v: Value<'_> = o.into();
        assert_eq!(v.value_signature(), "o");
        let encoded = value_test!(LE, DBus, v, 21);
        let ctxt = Context::new_dbus(0);
        let v = from_slice::<LE, Value<'_>>(&encoded, ctxt).unwrap();
        assert_eq!(
            v,
            Value::ObjectPath(ObjectPath::try_from("/hello/world").unwrap())
        );

        // GVariant format now
        #[cfg(feature = "gvariant")]
        {
            let encoded = value_test!(LE, GVariant, v, 15);
            let ctxt = Context::new_gvariant(0);
            let v = from_slice::<LE, Value<'_>>(&encoded, ctxt).unwrap();
            assert_eq!(
                v,
                Value::ObjectPath(ObjectPath::try_from("/hello/world").unwrap())
            );
        }
    }

    #[test]
    fn unit() {
        let ctxt = Context::<BE>::new_dbus(0);
        let (encoded, fds) = to_bytes_fds(ctxt, &()).unwrap();
        assert_eq!(encoded.len(), 0, "invalid encoding using `to_bytes`");
        let decoded: () = from_slice_fds(&encoded, Some(&fds), ctxt).unwrap();
        assert_eq!(decoded, (), "invalid decoding using `from_slice`");
    }

    #[test]
    fn array_value() {
        // Let's use D-Bus/GVariant terms

        //
        // Array of u8
        //
        // First a normal Rust array that is actually serialized as a struct (thank you Serde!)
        let ay = [77u8, 88];
        let ctxt = Context::<LE>::new_dbus(0);
        let encoded = to_bytes(ctxt, &ay).unwrap();
        assert_eq!(encoded.len(), 2);
        let decoded: [u8; 2] = from_slice(&encoded, ctxt).unwrap();
        assert_eq!(&decoded, &[77u8, 88]);

        // Then rest of the tests just use ArrayVec or Vec
        #[cfg(feature = "arrayvec")]
        let ay = ArrayVec::from([77u8, 88]);
        #[cfg(not(feature = "arrayvec"))]
        let ay = vec![77u8, 88];
        let ctxt = Context::<LE>::new_dbus(0);
        let encoded = to_bytes(ctxt, &ay).unwrap();
        assert_eq!(encoded.len(), 6);

        #[cfg(feature = "arrayvec")]
        let decoded: ArrayVec<[u8; 2]> = from_slice(&encoded, ctxt).unwrap();
        #[cfg(not(feature = "arrayvec"))]
        let decoded: Vec<u8> = from_slice(&encoded, ctxt).unwrap();
        assert_eq!(&decoded.as_slice(), &[77u8, 88]);

        // GVariant format now
        #[cfg(feature = "gvariant")]
        {
            let ctxt = Context::<LE>::new_gvariant(0);
            let gv_encoded = to_bytes(ctxt, &ay).unwrap();
            assert_eq!(gv_encoded.len(), 2);

            // Check encoding against GLib
            let bytes = Bytes::from_owned(gv_encoded);
            let variant = Variant::from_bytes::<&[u8]>(&bytes);
            assert_eq!(variant.n_children(), 2);
            assert_eq!(variant.get_child_value(0).get::<u8>().unwrap(), 77);
            assert_eq!(variant.get_child_value(1).get::<u8>().unwrap(), 88);
        }
        let ctxt = Context::<LE>::new_dbus(0);

        // As Value
        let v: Value<'_> = ay[..].into();
        assert_eq!(v.value_signature(), "ay");
        let encoded = to_bytes::<LE, _>(ctxt, &v).unwrap();
        assert_eq!(encoded.len(), 10);
        let v = from_slice::<LE, Value<'_>>(&encoded, ctxt).unwrap();
        if let Value::Array(array) = v {
            assert_eq!(*array.element_signature(), "y");
            assert_eq!(array.len(), 2);
            assert_eq!(array.get()[0], Value::U8(77));
            assert_eq!(array.get()[1], Value::U8(88));
        } else {
            panic!();
        }

        // Now try as Vec
        let vec = ay.to_vec();
        let encoded = to_bytes::<LE, _>(ctxt, &vec).unwrap();
        assert_eq!(encoded.len(), 6);

        // Vec as Value
        let v: Value<'_> = Array::from(&vec).into();
        assert_eq!(v.value_signature(), "ay");
        let encoded = to_bytes::<LE, _>(ctxt, &v).unwrap();
        assert_eq!(encoded.len(), 10);

        // Emtpy array
        let at: Vec<u64> = vec![];
        let encoded = to_bytes::<LE, _>(ctxt, &at).unwrap();
        assert_eq!(encoded.len(), 8);

        // GVariant format now
        #[cfg(feature = "gvariant")]
        {
            let ctxt = Context::<LE>::new_gvariant(0);
            let gv_encoded = to_bytes(ctxt, &at).unwrap();
            assert_eq!(gv_encoded.len(), 0);
            let at = from_slice::<LE, Vec<u64>>(&gv_encoded, ctxt).unwrap();
            assert_eq!(at.len(), 0);
        }
        let ctxt = Context::<LE>::new_dbus(0);

        // As Value
        let v: Value<'_> = at[..].into();
        assert_eq!(v.value_signature(), "at");
        let encoded = to_bytes::<LE, _>(ctxt, &v).unwrap();
        assert_eq!(encoded.len(), 8);
        let v = from_slice::<LE, Value<'_>>(&encoded, ctxt).unwrap();
        if let Value::Array(array) = v {
            assert_eq!(*array.element_signature(), "t");
            assert_eq!(array.len(), 0);
        } else {
            panic!();
        }

        // GVariant format now
        #[cfg(feature = "gvariant")]
        {
            let ctxt = Context::<LE>::new_gvariant(0);
            let v: Value<'_> = at[..].into();
            let gv_encoded = to_bytes(ctxt, &v).unwrap();
            assert_eq!(gv_encoded.len(), 3);
            let v = from_slice::<LE, Value<'_>>(&gv_encoded, ctxt).unwrap();
            if let Value::Array(array) = v {
                assert_eq!(*array.element_signature(), "t");
                assert_eq!(array.len(), 0);
            } else {
                panic!();
            }

            // Check encoding against GLib
            let bytes = Bytes::from_owned(gv_encoded);
            let variant = Variant::from_bytes::<&[&str]>(&bytes);
            assert_eq!(variant.n_children(), 0);
        }
        let ctxt = Context::<LE>::new_dbus(0);

        //
        // Array of strings
        //
        // Can't use 'as' as it's a keyword
        let as_ = vec!["Hello", "World", "Now", "Bye!"];
        let encoded = to_bytes::<LE, _>(ctxt, &as_).unwrap();
        assert_eq!(encoded.len(), 45);
        let decoded = from_slice::<LE, Vec<&str>>(&encoded, ctxt).unwrap();
        assert_eq!(decoded.len(), 4);
        assert_eq!(decoded[0], "Hello");
        assert_eq!(decoded[1], "World");

        let decoded = from_slice::<LE, Vec<String>>(&encoded, ctxt).unwrap();
        assert_eq!(decoded.as_slice(), as_.as_slice());

        // Decode just the second string
        let ctxt = Context::<LE>::new_dbus(14);
        let decoded: &str = from_slice(&encoded[14..], ctxt).unwrap();
        assert_eq!(decoded, "World");
        let ctxt = Context::<LE>::new_dbus(0);

        // As Value
        let v: Value<'_> = as_[..].into();
        assert_eq!(v.value_signature(), "as");
        let encoded = to_bytes(ctxt, &v).unwrap();
        assert_eq!(encoded.len(), 49);
        let v = from_slice(&encoded, ctxt).unwrap();
        if let Value::Array(array) = v {
            assert_eq!(*array.element_signature(), "s");
            assert_eq!(array.len(), 4);
            assert_eq!(array.get()[0], Value::new("Hello"));
            assert_eq!(array.get()[1], Value::new("World"));
        } else {
            panic!();
        }

        let v: Value<'_> = as_[..].into();
        let a: Array<'_> = v.try_into().unwrap();
        let _ve: Vec<String> = a.try_into().unwrap();

        // GVariant format now
        #[cfg(feature = "gvariant")]
        {
            let ctxt = Context::<LE>::new_gvariant(0);
            let v: Value<'_> = as_[..].into();
            let gv_encoded = to_bytes(ctxt, &v).unwrap();
            assert_eq!(gv_encoded.len(), 28);

            // Check encoding against GLib
            let bytes = Bytes::from_owned(gv_encoded);
            let variant = Variant::from_bytes::<Variant>(&bytes);
            assert_eq!(variant.n_children(), 1);
            let decoded: Vec<String> = variant.get_child_value(0).get().unwrap();
            assert_eq!(decoded[0], "Hello");
            assert_eq!(decoded[1], "World");
        }

        // Array of Struct, which in turn containin an Array (We gotta go deeper!)
        // Signature: "a(yu(xbxas)s)");
        let ar = vec![(
            // top-most simple fields
            u8::max_value(),
            u32::max_value(),
            (
                // 2nd level simple fields
                i64::max_value(),
                true,
                i64::max_value(),
                // 2nd level array field
                &["Hello", "World"][..],
            ),
            // one more top-most simple field
            "hello",
        )];
        let ctxt = Context::<LE>::new_dbus(0);
        let encoded = to_bytes(ctxt, &ar).unwrap();
        assert_eq!(encoded.len(), 78);
        let decoded =
            from_slice::<LE, Vec<(u8, u32, (i64, bool, i64, Vec<&str>), &str)>>(&encoded, ctxt)
                .unwrap();
        assert_eq!(decoded.len(), 1);
        let r = &decoded[0];
        assert_eq!(r.0, u8::max_value());
        assert_eq!(r.1, u32::max_value());
        let inner_r = &r.2;
        assert_eq!(inner_r.0, i64::max_value());
        assert_eq!(inner_r.1, true);
        assert_eq!(inner_r.2, i64::max_value());
        let as_ = &inner_r.3;
        assert_eq!(as_.len(), 2);
        assert_eq!(as_[0], "Hello");
        assert_eq!(as_[1], "World");
        assert_eq!(r.3, "hello");

        // GVariant format now
        #[cfg(feature = "gvariant")]
        {
            let ctxt = Context::<LE>::new_gvariant(0);
            let gv_encoded = to_bytes(ctxt, &ar).unwrap();
            assert_eq!(gv_encoded.len(), 54);
            let decoded = from_slice::<LE, Vec<(u8, u32, (i64, bool, i64, Vec<&str>), &str)>>(
                &gv_encoded,
                ctxt,
            )
            .unwrap();
            assert_eq!(decoded.len(), 1);
            let r = &decoded[0];
            assert_eq!(r.0, u8::max_value());
            assert_eq!(r.1, u32::max_value());
            let inner_r = &r.2;
            assert_eq!(inner_r.0, i64::max_value());
            assert_eq!(inner_r.1, true);
            assert_eq!(inner_r.2, i64::max_value());
            let as_ = &inner_r.3;
            assert_eq!(as_.len(), 2);
            assert_eq!(as_[0], "Hello");
            assert_eq!(as_[1], "World");
            assert_eq!(r.3, "hello");

            // Check encoding against GLib
            let bytes = Bytes::from_owned(gv_encoded);
            let variant = Variant::from_bytes::<
                Vec<(u8, u32, (i64, bool, i64, Vec<String>), String)>,
            >(&bytes);
            assert_eq!(variant.n_children(), 1);
            let r: (u8, u32, (i64, bool, i64, Vec<String>), String) =
                variant.get_child_value(0).get().unwrap();
            assert_eq!(r.0, u8::max_value());
            assert_eq!(r.1, u32::max_value());
        }
        let ctxt = Context::<LE>::new_dbus(0);

        // As Value
        let v: Value<'_> = ar[..].into();
        assert_eq!(v.value_signature(), "a(yu(xbxas)s)");
        let encoded = to_bytes::<LE, _>(ctxt, &v).unwrap();
        assert_eq!(encoded.len(), 94);
        let v = from_slice::<LE, Value<'_>>(&encoded, ctxt).unwrap();
        if let Value::Array(array) = v.clone() {
            assert_eq!(*array.element_signature(), "(yu(xbxas)s)");
            assert_eq!(array.len(), 1);
            let r = &array.get()[0];
            if let Value::Structure(r) = r {
                let fields = r.fields();
                assert_eq!(fields[0], Value::U8(u8::max_value()));
                assert_eq!(fields[1], Value::U32(u32::max_value()));
                if let Value::Structure(r) = &fields[2] {
                    let fields = r.fields();
                    assert_eq!(fields[0], Value::I64(i64::max_value()));
                    assert_eq!(fields[1], Value::Bool(true));
                    assert_eq!(fields[2], Value::I64(i64::max_value()));
                    if let Value::Array(as_) = &fields[3] {
                        assert_eq!(as_.len(), 2);
                        assert_eq!(as_.get()[0], Value::new("Hello"));
                        assert_eq!(as_.get()[1], Value::new("World"));
                    } else {
                        panic!();
                    }
                } else {
                    panic!();
                }
                assert_eq!(fields[3], Value::new("hello"));
            } else {
                panic!();
            }
        } else {
            panic!();
        }

        // GVariant format now
        #[cfg(feature = "gvariant")]
        {
            use rand::{distributions::Alphanumeric, thread_rng, Rng};

            let ctxt = Context::<LE>::new_gvariant(0);
            let gv_encoded = to_bytes(ctxt, &v).unwrap();
            assert_eq!(gv_encoded.len(), 68);
            let v = from_slice::<LE, Value<'_>>(&gv_encoded, ctxt).unwrap();
            if let Value::Array(array) = v {
                assert_eq!(*array.element_signature(), "(yu(xbxas)s)");
                assert_eq!(array.len(), 1);
                let r = &array.get()[0];
                if let Value::Structure(r) = r {
                    let fields = r.fields();
                    assert_eq!(fields[0], Value::U8(u8::max_value()));
                    assert_eq!(fields[1], Value::U32(u32::max_value()));
                    if let Value::Structure(r) = &fields[2] {
                        let fields = r.fields();
                        assert_eq!(fields[0], Value::I64(i64::max_value()));
                        assert_eq!(fields[1], Value::Bool(true));
                        assert_eq!(fields[2], Value::I64(i64::max_value()));
                        if let Value::Array(as_) = &fields[3] {
                            assert_eq!(as_.len(), 2);
                            assert_eq!(as_.get()[0], Value::new("Hello"));
                            assert_eq!(as_.get()[1], Value::new("World"));
                        } else {
                            panic!();
                        }
                    } else {
                        panic!();
                    }
                    assert_eq!(fields[3], Value::new("hello"));
                } else {
                    panic!();
                }
            } else {
                panic!();
            }

            // Check encoding against GLib
            let bytes = Bytes::from_owned(gv_encoded);
            let variant = Variant::from_bytes::<Variant>(&bytes);
            assert_eq!(variant.n_children(), 1);
            let child: Variant = variant.get_child_value(0);
            let r: (u8, u32, (i64, bool, i64, Vec<String>), String) =
                child.get_child_value(0).get().unwrap();
            assert_eq!(r.0, u8::max_value());
            assert_eq!(r.1, u32::max_value());

            let rng = thread_rng();
            // Let's test GVariant ser/de of a 254 byte array with variable-width elements as to ensure
            // no problems with non-normal BS of GVariant.
            let as_ = vec![
                rng.sample_iter(Alphanumeric).take(126).collect::<String>(),
                rng.sample_iter(Alphanumeric).take(126).collect::<String>(),
            ];
            let gv_encoded = to_bytes(ctxt, &as_).unwrap();
            // 252 chars + 2 null terminator bytes doesn't leave room for 2 framing offset bytes so a
            // 2-byte offset is chosen by the serializer.
            assert_eq!(gv_encoded.len(), 258);

            // Check encoding against GLib
            let bytes = Bytes::from_owned(gv_encoded.clone());
            let variant = Variant::from_bytes::<Vec<String>>(&bytes);
            assert_eq!(variant.n_children(), 2);
            assert_eq!(variant.get_child_value(0).get::<String>().unwrap(), as_[0]);
            assert_eq!(variant.get_child_value(1).get::<String>().unwrap(), as_[1]);
            // Also check if our own deserializer does the right thing
            let as2 = from_slice::<LE, Vec<String>>(&gv_encoded, ctxt).unwrap();
            assert_eq!(as2, as_);

            // Test conversion of Array of Value to Vec<Value>
            let v = Value::new(vec![Value::new(43), Value::new("bonjour")]);
            let av = <Array<'_>>::try_from(v).unwrap();
            let av = <Vec<Value<'_>>>::try_from(av).unwrap();
            assert_eq!(av[0], Value::new(43));
            assert_eq!(av[1], Value::new("bonjour"));

            let vec = vec![1, 2];
            let val = Value::new(&vec);
            assert_eq!(TryInto::<Vec<i32>>::try_into(val).unwrap(), vec);
        }
    }

    #[test]
    fn struct_value() {
        // Struct->Value
        let s: Value<'_> = ("a", "b", (1, 2)).into();

        let ctxt = Context::<LE>::new_dbus(0);
        let encoded = to_bytes(ctxt, &s).unwrap();
        assert_eq!(dbg!(encoded.len()), 40);
        let decoded: Value<'_> = from_slice(&encoded, ctxt).unwrap();
        let s = <Structure<'_>>::try_from(decoded).unwrap();
        let outer = <(Str<'_>, Str<'_>, Structure<'_>)>::try_from(s).unwrap();
        assert_eq!(outer.0, "a");
        assert_eq!(outer.1, "b");

        let inner = <(i32, i32)>::try_from(outer.2).unwrap();
        assert_eq!(inner.0, 1);
        assert_eq!(inner.1, 2);

        #[derive(Serialize, Deserialize, Type, PartialEq, Debug)]
        struct Foo {
            val: u32,
        }

        let foo = Foo { val: 99 };
        let v = SerializeValue(&foo);
        let encoded = to_bytes(ctxt, &v).unwrap();
        let decoded: DeserializeValue<'_, Foo> = from_slice(&encoded, ctxt).unwrap();
        assert_eq!(decoded.0, foo);
    }

    #[test]
    fn struct_ref() {
        let ctxt = Context::<LE>::new_dbus(0);
        let encoded = to_bytes(ctxt, &(&1u32, &2u32)).unwrap();
        let decoded: [u32; 2] = from_slice(&encoded, ctxt).unwrap();
        assert_eq!(decoded, [1u32, 2u32]);
    }

    #[test]
    fn dict_value() {
        let mut map: HashMap<i64, &str> = HashMap::new();
        map.insert(1, "123");
        map.insert(2, "456");
        let ctxt = Context::<LE>::new_dbus(0);
        let encoded = to_bytes(ctxt, &map).unwrap();
        assert_eq!(dbg!(encoded.len()), 40);
        let decoded: HashMap<i64, &str> = from_slice(&encoded, ctxt).unwrap();
        assert_eq!(decoded[&1], "123");
        assert_eq!(decoded[&2], "456");

        // GVariant format now
        #[cfg(feature = "gvariant")]
        {
            let ctxt = Context::<LE>::new_gvariant(0);
            let gv_encoded = to_bytes(ctxt, &map).unwrap();
            assert_eq!(gv_encoded.len(), 30);
            let map: HashMap<i64, &str> = from_slice(&gv_encoded, ctxt).unwrap();
            assert_eq!(map[&1], "123");
            assert_eq!(map[&2], "456");

            // Check encoding against GLib
            let bytes = Bytes::from_owned(gv_encoded);
            let variant = Variant::from_bytes::<HashMap<i64, &str>>(&bytes);
            assert_eq!(variant.n_children(), 2);
            let map: HashMap<i64, String> = HashMap::from_variant(&variant).unwrap();
            assert_eq!(map[&1], "123");
            assert_eq!(map[&2], "456");
        }
        let ctxt = Context::<LE>::new_dbus(0);

        // As Value
        let v: Value<'_> = Dict::from(map).into();
        assert_eq!(v.value_signature(), "a{xs}");
        let encoded = to_bytes(ctxt, &v).unwrap();
        assert_eq!(encoded.len(), 48);
        // Convert it back
        let dict: Dict<'_, '_> = v.try_into().unwrap();
        let map: HashMap<i64, String> = dict.try_into().unwrap();
        assert_eq!(map[&1], "123");
        assert_eq!(map[&2], "456");
        // Also decode it back
        let v = from_slice(&encoded, ctxt).unwrap();
        if let Value::Dict(dict) = v {
            assert_eq!(dict.get::<i64, str>(&1).unwrap().unwrap(), "123");
            assert_eq!(dict.get::<i64, str>(&2).unwrap().unwrap(), "456");
        } else {
            panic!();
        }

        #[cfg(feature = "gvariant")]
        {
            // GVariant-format requires framing offsets for dict entries with variable-length keys so
            // let's test that.
            let mut map: HashMap<&str, &str> = HashMap::new();
            map.insert("hi", "1234");
            map.insert("world", "561");
            let ctxt = Context::<LE>::new_gvariant(0);
            let gv_encoded = to_bytes(ctxt, &map).unwrap();
            assert_eq!(gv_encoded.len(), 22);
            let map: HashMap<&str, &str> = from_slice(&gv_encoded, ctxt).unwrap();
            assert_eq!(map["hi"], "1234");
            assert_eq!(map["world"], "561");

            // Check encoding against GLib
            let bytes = Bytes::from_owned(gv_encoded);
            let variant = Variant::from_bytes::<HashMap<&str, &str>>(&bytes);
            assert_eq!(variant.n_children(), 2);
            let map: HashMap<String, String> = HashMap::from_variant(&variant).unwrap();
            assert_eq!(map["hi"], "1234");
            assert_eq!(map["world"], "561");

            // Now the same but empty dict this time
            let map: HashMap<&str, &str> = HashMap::new();
            let gv_encoded = to_bytes(ctxt, &map).unwrap();
            assert_eq!(gv_encoded.len(), 0);
            let map: HashMap<&str, &str> = from_slice(&gv_encoded, ctxt).unwrap();
            assert_eq!(map.len(), 0);
        }
        let ctxt = Context::<LE>::new_dbus(0);

        // Now a hand-crafted Dict Value but with a Value as value
        let mut dict = Dict::new(<&str>::signature(), Value::signature());
        dict.add("hello", Value::new("there")).unwrap();
        dict.add("bye", Value::new("now")).unwrap();
        let v: Value<'_> = dict.into();
        assert_eq!(v.value_signature(), "a{sv}");
        let encoded = to_bytes(ctxt, &v).unwrap();
        assert_eq!(dbg!(encoded.len()), 68);
        let v: Value<'_> = from_slice(&encoded, ctxt).unwrap();
        if let Value::Dict(dict) = v {
            assert_eq!(
                *dict.get::<_, Value<'_>>("hello").unwrap().unwrap(),
                Value::new("there")
            );
            assert_eq!(
                *dict.get::<_, Value<'_>>("bye").unwrap().unwrap(),
                Value::new("now")
            );

            // Try converting to a HashMap
            let map = <HashMap<String, Value<'_>>>::try_from(dict).unwrap();
            assert_eq!(map["hello"], Value::new("there"));
            assert_eq!(map["bye"], Value::new("now"));
        } else {
            panic!();
        }

        #[derive(SerializeDict, DeserializeDict, TypeDict, PartialEq, Debug)]
        struct Test {
            process_id: Option<u32>,
            group_id: Option<u32>,
            user: String,
        }
        let test = Test {
            process_id: Some(42),
            group_id: None,
            user: "me".to_string(),
        };

        let encoded = to_bytes(ctxt, &test).unwrap();
        assert_eq!(encoded.len(), 51);

        let decoded: HashMap<&str, Value<'_>> = from_slice(&encoded, ctxt).unwrap();
        assert_eq!(decoded["process_id"], Value::U32(42));
        assert_eq!(decoded["user"], Value::new("me"));
        assert!(!decoded.contains_key("group_id"));

        let decoded: Test = from_slice(&encoded, ctxt).unwrap();
        assert_eq!(decoded, test);

        #[derive(SerializeDict, DeserializeDict, TypeDict, PartialEq, Debug)]
        struct TestMissing {
            process_id: Option<u32>,
            group_id: Option<u32>,
            user: String,
            quota: u8,
        }
        let decoded: Result<TestMissing> = from_slice(&encoded, ctxt);
        assert_eq!(
            decoded.unwrap_err(),
            Error::Message("missing field `quota`".to_string())
        );

        #[derive(SerializeDict, DeserializeDict, TypeDict, PartialEq, Debug)]
        struct TestSkipUnknown {
            process_id: Option<u32>,
            group_id: Option<u32>,
        }
        let _: TestSkipUnknown = from_slice(&encoded, ctxt).unwrap();

        #[derive(SerializeDict, DeserializeDict, TypeDict, PartialEq, Debug)]
        #[zvariant(deny_unknown_fields)]
        struct TestUnknown {
            process_id: Option<u32>,
            group_id: Option<u32>,
        }
        let decoded: Result<TestUnknown> = from_slice(&encoded, ctxt);
        assert_eq!(
            decoded.unwrap_err(),
            Error::Message("unknown field `user`, expected `process_id` or `group_id`".to_string())
        );
    }

    #[test]
    fn value_value() {
        let ctxt = Context::<BE>::new_dbus(0);
        let encoded = to_bytes(ctxt, &0xABBA_ABBA_ABBA_ABBA_u64).unwrap();
        assert_eq!(encoded.len(), 8);
        assert_eq!(LE::read_u64(&encoded), 0xBAAB_BAAB_BAAB_BAAB_u64);
        let decoded: u64 = from_slice(&encoded, ctxt).unwrap();
        assert_eq!(decoded, 0xABBA_ABBA_ABBA_ABBA);

        // Lie about there being bytes before
        let ctxt = Context::<LE>::new_dbus(2);
        let encoded = to_bytes(ctxt, &0xABBA_ABBA_ABBA_ABBA_u64).unwrap();
        assert_eq!(encoded.len(), 14);
        let decoded: u64 = from_slice(&encoded, ctxt).unwrap();
        assert_eq!(decoded, 0xABBA_ABBA_ABBA_ABBA_u64);
        let ctxt = Context::<LE>::new_dbus(0);

        // As Value
        let v: Value<'_> = 0xFEFE_u64.into();
        assert_eq!(v.value_signature(), "t");
        let encoded = to_bytes(ctxt, &v).unwrap();
        assert_eq!(encoded.len(), 16);
        let v = from_slice(&encoded, ctxt).unwrap();
        assert_eq!(v, Value::U64(0xFEFE));

        // And now as Value in a Value
        let v = Value::Value(Box::new(v));
        let encoded = to_bytes(ctxt, &v).unwrap();
        assert_eq!(encoded.len(), 16);
        let v = from_slice(&encoded, ctxt).unwrap();
        if let Value::Value(v) = v {
            assert_eq!(v.value_signature(), "t");
            assert_eq!(*v, Value::U64(0xFEFE));
        } else {
            panic!();
        }

        // Ensure Value works with other Serializer & Deserializer
        let v: Value<'_> = 0xFEFE_u64.into();
        let encoded = serde_json::to_string(&v).unwrap();
        let v = serde_json::from_str::<Value<'_>>(&encoded).unwrap();
        assert_eq!(v, Value::U64(0xFEFE));
    }

    #[test]
    fn enums() {
        // TODO: Document enum handling.
        //
        // 1. `Value`.
        // 2. custom (de)serialize impl.
        // 3. to/from_*_for_signature()
        use serde::{Deserialize, Serialize};

        #[derive(Debug, PartialEq, Eq, Serialize, Deserialize)]
        enum Test {
            Unit,
            NewType(u8),
            Tuple(u8, u64),
            Struct { y: u8, t: u64 },
        }

        let ctxt = Context::<BE>::new_dbus(0);
        let signature = "u".try_into().unwrap();
        let encoded = to_bytes_for_signature(ctxt, &signature, &Test::Unit).unwrap();
        assert_eq!(encoded.len(), 4);
        let decoded: Test = from_slice_for_signature(&encoded, ctxt, &signature).unwrap();
        assert_eq!(decoded, Test::Unit);

        let signature = "y".try_into().unwrap();
        let encoded = to_bytes_for_signature(ctxt, &signature, &Test::NewType(42)).unwrap();
        assert_eq!(encoded.len(), 5);
        let decoded: Test = from_slice_for_signature(&encoded, ctxt, &signature).unwrap();
        assert_eq!(decoded, Test::NewType(42));

        // TODO: Provide convenience API to create complex signatures
        let signature = "(yt)".try_into().unwrap();
        let encoded = to_bytes_for_signature(ctxt, &signature, &Test::Tuple(42, 42)).unwrap();
        assert_eq!(encoded.len(), 24);
        let decoded: Test = from_slice_for_signature(&encoded, ctxt, &signature).unwrap();
        assert_eq!(decoded, Test::Tuple(42, 42));

        let s = Test::Struct { y: 42, t: 42 };
        let encoded = to_bytes_for_signature(ctxt, &signature, &s).unwrap();
        assert_eq!(encoded.len(), 24);
        let decoded: Test = from_slice_for_signature(&encoded, ctxt, &signature).unwrap();
        assert_eq!(decoded, Test::Struct { y: 42, t: 42 });
    }

    #[test]
    fn derive() {
        use serde::{Deserialize, Serialize};
        use serde_repr::{Deserialize_repr, Serialize_repr};

        #[derive(Deserialize, Serialize, Type, PartialEq, Debug)]
        struct Struct<'s> {
            field1: u16,
            field2: i64,
            field3: &'s str,
        }

        assert_eq!(Struct::signature(), "(qxs)");
        let s = Struct {
            field1: 0xFF_FF,
            field2: 0xFF_FF_FF_FF_FF_FF,
            field3: "hello",
        };
        let ctxt = Context::<LE>::new_dbus(0);
        let encoded = to_bytes(ctxt, &s).unwrap();
        assert_eq!(encoded.len(), 26);
        let decoded: Struct<'_> = from_slice(&encoded, ctxt).unwrap();
        assert_eq!(decoded, s);

        #[derive(Deserialize, Serialize, Type)]
        struct UnitStruct;

        assert_eq!(UnitStruct::signature(), <()>::signature());
        let encoded = to_bytes(ctxt, &UnitStruct).unwrap();
        assert_eq!(encoded.len(), 0);
        let _: UnitStruct = from_slice(&encoded, ctxt).unwrap();

        #[repr(u8)]
        #[derive(Deserialize_repr, Serialize_repr, Type, Debug, PartialEq)]
        enum Enum {
            Variant1,
            Variant2,
            Variant3,
        }

        assert_eq!(Enum::signature(), u8::signature());
        let encoded = to_bytes(ctxt, &Enum::Variant3).unwrap();
        assert_eq!(encoded.len(), 1);
        let decoded: Enum = from_slice(&encoded, ctxt).unwrap();
        assert_eq!(decoded, Enum::Variant3);

        #[repr(i64)]
        #[derive(Deserialize_repr, Serialize_repr, Type, Debug, PartialEq)]
        enum Enum2 {
            Variant1,
            Variant2,
            Variant3,
        }

        assert_eq!(Enum2::signature(), i64::signature());
        let encoded = to_bytes(ctxt, &Enum2::Variant2).unwrap();
        assert_eq!(encoded.len(), 8);
        let decoded: Enum2 = from_slice(&encoded, ctxt).unwrap();
        assert_eq!(decoded, Enum2::Variant2);

        #[derive(Deserialize, Serialize, Type, Debug, PartialEq)]
        enum NoReprEnum {
            Variant1,
            Variant2,
            Variant3,
        }

        assert_eq!(NoReprEnum::signature(), u32::signature());
        let encoded = to_bytes(ctxt, &NoReprEnum::Variant2).unwrap();
        assert_eq!(encoded.len(), 4);
        let decoded: NoReprEnum = from_slice(&encoded, ctxt).unwrap();
        assert_eq!(decoded, NoReprEnum::Variant2);
    }

    #[test]
    fn serialized_size() {
        let ctxt = Context::<LE>::new_dbus(0);
        let l = crate::serialized_size(ctxt, &()).unwrap();
        assert_eq!(l, 0);

        let stdout = std::io::stdout();
        let l = crate::serialized_size_fds(ctxt, &Fd::from(&stdout)).unwrap();
        assert_eq!(l, (4, 1));

        let l = crate::serialized_size(ctxt, &('a', "abc", &(1_u32, 2))).unwrap();
        assert_eq!(l, 24);

        let v = vec![1, 2];
        let l = crate::serialized_size(ctxt, &('a', "abc", &v)).unwrap();
        assert_eq!(l, 28);
    }

    #[test]
    #[cfg(feature = "gvariant")]
    fn option_value() {
        let ctxt = Context::<LE>::new_gvariant(0);

        // First a Some fixed-sized value
        let mn = Some(16i16);
        let encoded = to_bytes(ctxt, &mn).unwrap();
        assert_eq!(encoded.len(), 2);
        let decoded: Option<i16> = from_slice(&encoded, ctxt).unwrap();
        assert_eq!(decoded, mn);

        // Check encoding against GLib
        let bytes = Bytes::from_owned(encoded);
        let variant = Variant::from_bytes::<Option<i16>>(&bytes);
        assert_eq!(variant.get::<Option<i16>>().unwrap(), mn);

        // As Value
        let v: Value<'_> = mn.into();
        let encoded = to_bytes(ctxt, &v).unwrap();
        assert_eq!(encoded.len(), 5);
        let decoded: Value<'_> = from_slice(&encoded, ctxt).unwrap();
        if let Value::Maybe(maybe) = decoded {
            assert_eq!(maybe.get().unwrap(), mn);
        } else {
            panic!();
        }

        // Check encoding against GLib
        let bytes = Bytes::from_owned(encoded);
        let variant = Variant::from_bytes::<Variant>(&bytes);
        let decoded = variant.get_child_value(0).get::<Option<i16>>().unwrap();
        assert_eq!(decoded, mn);

        // Now a None of the same type
        let mn: Option<i16> = None;
        let encoded = to_bytes(ctxt, &mn).unwrap();
        assert_eq!(encoded.len(), 0);
        let decoded: Option<i16> = from_slice(&encoded, ctxt).unwrap();
        assert!(decoded.is_none());

        // Check encoding against GLib
        let bytes = Bytes::from_owned(encoded);
        let variant = Variant::from_bytes::<Option<i16>>(&bytes);
        assert!(variant.get::<Option<i16>>().unwrap().is_none());

        // Next a Some variable-sized value
        let ms = Some("hello world");
        let encoded = to_bytes(ctxt, &ms).unwrap();
        assert_eq!(encoded.len(), 13);
        let decoded: Option<&str> = from_slice(&encoded, ctxt).unwrap();
        assert_eq!(decoded, ms);

        // Check encoding against GLib
        let bytes = Bytes::from_owned(encoded);
        let variant = Variant::from_bytes::<Option<String>>(&bytes);
        assert_eq!(
            &variant.get::<Option<String>>().unwrap().unwrap(),
            ms.unwrap()
        );

        // As Value
        let v: Value<'_> = ms.into();
        let encoded = to_bytes(ctxt, &v).unwrap();
        assert_eq!(encoded.len(), 16);
        let decoded: Value<'_> = from_slice(&encoded, ctxt).unwrap();
        if let Value::Maybe(maybe) = decoded {
            assert_eq!(maybe.get::<String>().unwrap().as_deref(), ms);
        } else {
            panic!();
        }

        // Check encoding against GLib
        let bytes = Bytes::from_owned(encoded);
        let variant = Variant::from_bytes::<Variant>(&bytes);
        let decoded = variant.get_child_value(0).get::<Option<String>>().unwrap();
        assert_eq!(decoded.as_deref(), ms);

        // Now a None of the same type
        let ms: Option<&str> = None;
        let encoded = to_bytes(ctxt, &ms).unwrap();
        assert_eq!(encoded.len(), 0);
        let decoded: Option<&str> = from_slice(&encoded, ctxt).unwrap();
        assert!(decoded.is_none());

        // Check encoding against GLib
        let bytes = Bytes::from_owned(encoded);
        let variant = Variant::from_bytes::<Option<String>>(&bytes);
        assert!(variant.get::<Option<String>>().unwrap().is_none());

        // In a seq type
        let ams = vec![
            Some(String::from("hello world")),
            Some(String::from("bye world")),
        ];
        let encoded = to_bytes(ctxt, &ams).unwrap();
        assert_eq!(encoded.len(), 26);
        let decoded: Vec<Option<String>> = from_slice(&encoded, ctxt).unwrap();
        assert_eq!(decoded, ams);

        // Check encoding against GLib
        let bytes = Bytes::from_owned(encoded);
        let variant = Variant::from_bytes::<Vec<Option<String>>>(&bytes);
        let decoded = variant.get::<Vec<Option<String>>>().unwrap();
        assert_eq!(decoded, ams);

        // As Value
        let v: Value<'_> = ams.clone().into();
        let encoded = to_bytes(ctxt, &v).unwrap();
        assert_eq!(encoded.len(), 30);
        let decoded: Value<'_> = from_slice(&encoded, ctxt).unwrap();
        assert_eq!(v, decoded);

        // Check encoding against GLib
        let bytes = Bytes::from_owned(encoded);
        let variant = Variant::from_bytes::<Variant>(&bytes);
        let decoded = variant
            .get_child_value(0)
            .get::<Vec<Option<String>>>()
            .unwrap();
        assert_eq!(decoded, ams);

        // In a struct
        let structure: (Option<String>, u64, Option<String>) =
            (Some(String::from("hello world")), 42u64, None);
        let encoded = to_bytes(ctxt, &structure).unwrap();
        assert_eq!(encoded.len(), 25);
        let decoded: (Option<String>, u64, Option<String>) = from_slice(&encoded, ctxt).unwrap();
        assert_eq!(decoded, structure);

        // Check encoding against GLib
        let bytes = Bytes::from_owned(encoded);
        let variant = Variant::from_bytes::<(Option<String>, u64, Option<String>)>(&bytes);
        let decoded = variant
            .get::<(Option<String>, u64, Option<String>)>()
            .unwrap();
        assert_eq!(decoded, structure);

        // As Value
        let v: Value<'_> = structure.clone().into();
        let encoded = to_bytes(ctxt, &v).unwrap();
        assert_eq!(encoded.len(), 33);
        let decoded: Value<'_> = from_slice(&encoded, ctxt).unwrap();
        assert_eq!(v, decoded);

        // Check encoding against GLib
        let bytes = Bytes::from_owned(encoded);
        let variant = Variant::from_bytes::<Variant>(&bytes);
        let decoded = variant
            .get_child_value(0)
            .get::<(Option<String>, u64, Option<String>)>()
            .unwrap();
        assert_eq!(decoded, structure);
    }

    #[test]
    fn struct_with_hashmap() {
        use serde::{Deserialize, Serialize};

        let mut hmap = HashMap::new();
        hmap.insert("key".into(), "value".into());

        #[derive(Type, Deserialize, Serialize, PartialEq, Debug)]
        struct Foo {
            hmap: HashMap<String, String>,
        }

        let foo = Foo { hmap };
        assert_eq!(Foo::signature(), "(a{ss})");

        let ctxt = Context::<LE>::new_dbus(0);
        let encoded = to_bytes(ctxt, &(&foo, 1)).unwrap();
        let f: Foo = from_slice_fds(&encoded, None, ctxt).unwrap();
        assert_eq!(f, foo);
    }

    #[test]
    fn issue_59() {
        // Ensure we don't panic on deserializing tuple of smaller than expected length.
        let ctxt = Context::<LE>::new_dbus(0);
        let (encoded, _) = to_bytes_fds(ctxt, &("hello",)).unwrap();
        let result: Result<(&str, &str)> = from_slice(&encoded, ctxt);
        assert!(result.is_err());
    }

    #[test]
    #[cfg(feature = "gvariant")]
    fn issue_99() {
        #[derive(Deserialize, Serialize, Type, PartialEq, Debug)]
        struct ZVStruct<'s>(#[serde(borrow)] HashMap<&'s str, Value<'s>>);

        let mut dict = HashMap::new();
        dict.insert("hi", Value::from("hello"));
        dict.insert("bye", Value::from("then"));

        let element = ZVStruct(dict);

        let ctxt = Context::<LE>::new_gvariant(0);
        let signature = ZVStruct::signature();

        let encoded = to_bytes_for_signature(ctxt, &signature, &element).unwrap();
        let _: ZVStruct<'_> = from_slice_for_signature(&encoded, ctxt, &signature).unwrap();
    }

    #[cfg(feature = "ostree-tests")]
    #[test]
    fn ostree_de() {
        #[derive(Deserialize, Serialize, Type, PartialEq, Debug)]
        struct Summary<'a>(Vec<Repo<'a>>, #[serde(borrow)] HashMap<&'a str, Value<'a>>);

        #[derive(Deserialize, Serialize, Type, PartialEq, Debug)]
        struct Repo<'a>(&'a str, #[serde(borrow)] Metadata<'a>);

        #[derive(Deserialize, Serialize, Type, PartialEq, Debug)]
        struct Metadata<'a>(u64, Vec<u8>, #[serde(borrow)] HashMap<&'a str, Value<'a>>);

        let encoded = std::fs::read("../test-data/flatpak-summary.dump").unwrap();
        let ctxt = Context::<LE>::new_gvariant(0);
        let _: Summary<'_> = from_slice(&encoded, ctxt).unwrap();
        // If we're able to deserialize all the data succesfully, don't bother checking the summary data.
    }
}