chore: checkpoint before Python removal

vendor/p256/tests/ecdsa.rs

@@ -0,0 +1,26 @@
+//! ECDSA tests.
+
+#![cfg(feature = "arithmetic")]
+
+use elliptic_curve::ops::Reduce;
+use p256::{
+    ecdsa::{SigningKey, VerifyingKey},
+    NonZeroScalar, U256,
+};
+use proptest::prelude::*;
+
+prop_compose! {
+    fn signing_key()(bytes in any::<[u8; 32]>()) -> SigningKey {
+        <NonZeroScalar as Reduce<U256>>::reduce_bytes(&bytes.into()).into()
+    }
+}
+
+proptest! {
+    #[test]
+    fn recover_from_msg(sk in signing_key()) {
+        let msg = b"example";
+        let (signature, v) = sk.sign_recoverable(msg).unwrap();
+        let recovered_vk = VerifyingKey::recover_from_msg(msg, &signature, v).unwrap();
+        prop_assert_eq!(sk.verifying_key(), &recovered_vk);
+    }
+}