From e5e22ee376bddc731a81ff877d1ec4f07996818d Mon Sep 17 00:00:00 2001
From: Elichai Turkel <elichai.turkel@gmail.com>
Date: Thu, 24 Oct 2019 21:05:04 +0300
Subject: [PATCH] Test serde support in no-std crate

---
 no_std_test/Cargo.toml  |  3 ++-
 no_std_test/src/main.rs | 13 +++++++++++++
 2 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/no_std_test/Cargo.toml b/no_std_test/Cargo.toml
index 77fb218..f68a47c 100644
--- a/no_std_test/Cargo.toml
+++ b/no_std_test/Cargo.toml
@@ -4,8 +4,9 @@ version = "0.1.0"
 authors = ["Elichai Turkel <elichai.turkel@gmail.com>"]
 
 [dependencies]
-secp256k1 = { path = "../", default-features = false, features = ["rand"] }
+secp256k1 = { path = "../", default-features = false, features = ["serde", "rand"] }
 libc = { version = "0.2", default-features = false }
+serde_cbor = { version = "0.10", default-features = false } # A random serializer that supports no-std.
 
 
 [profile.release]
diff --git a/no_std_test/src/main.rs b/no_std_test/src/main.rs
index 4ccbeb0..dfb63e2 100644
--- a/no_std_test/src/main.rs
+++ b/no_std_test/src/main.rs
@@ -5,6 +5,7 @@
 #![no_std]
 extern crate libc;
 extern crate secp256k1;
+extern crate serde_cbor;
 
 use core::fmt::{self, write, Write};
 use core::intrinsics;
@@ -14,6 +15,10 @@ use secp256k1::rand::{self, RngCore};
 use secp256k1::serde::Serialize;
 use secp256k1::*;
 
+use serde_cbor::de;
+use serde_cbor::ser::SliceWrite;
+use serde_cbor::Serializer;
+
 struct FakeRng;
 impl RngCore for FakeRng {
     fn next_u32(&mut self) -> u32 {
@@ -48,6 +53,14 @@ fn start(_argc: isize, _argv: *const *const u8) -> isize {
     let sig = secp.sign(&message, &secret_key);
     assert!(secp.verify(&message, &sig, &public_key).is_ok());
 
+    let mut cbor_ser = [0u8; 100];
+    let writer = SliceWrite::new(&mut cbor_ser[..]);
+    let mut ser = Serializer::new(writer);
+    sig.serialize(&mut ser).unwrap();
+    let size = ser.into_inner().bytes_written();
+    let new_sig: Signature = de::from_mut_slice(&mut cbor_ser[..size]).unwrap();
+    assert_eq!(sig, new_sig);
+
     unsafe { libc::printf("Verified Successfully!\n\0".as_ptr() as _) };
     0
 }