From 2295322e3c3d1921b205fab3cf13ec5bde5ad85e Mon Sep 17 00:00:00 2001
From: Paul Hauner <paul@paulhauner.com>
Date: Fri, 15 Mar 2019 15:33:14 +1100
Subject: [PATCH] Update DepositInput to spec v0.5.0

Also modifies the API for creating a proof of possession and adds a test
---
 eth2/types/src/deposit_data.rs                |  2 +-
 eth2/types/src/deposit_input.rs               | 43 +++++++++++++------
 .../src/test_utils/testing_deposit_builder.rs |  9 ++--
 3 files changed, 37 insertions(+), 17 deletions(-)

diff --git a/eth2/types/src/deposit_data.rs b/eth2/types/src/deposit_data.rs
index 9d6c1bda7..a1e30032f 100644
--- a/eth2/types/src/deposit_data.rs
+++ b/eth2/types/src/deposit_data.rs
@@ -7,7 +7,7 @@ use test_random_derive::TestRandom;
 
 /// Data generated by the deposit contract.
 ///
-/// Spec v0.4.0
+/// Spec v0.5.0
 #[derive(Debug, PartialEq, Clone, Serialize, Deserialize, Encode, Decode, TreeHash, TestRandom)]
 pub struct DepositData {
     pub amount: u64,
diff --git a/eth2/types/src/deposit_input.rs b/eth2/types/src/deposit_input.rs
index 9a9031901..9da53a042 100644
--- a/eth2/types/src/deposit_input.rs
+++ b/eth2/types/src/deposit_input.rs
@@ -9,7 +9,7 @@ use test_random_derive::TestRandom;
 
 /// The data supplied by the user to the deposit contract.
 ///
-/// Spec v0.4.0
+/// Spec v0.5.0
 #[derive(
     Debug,
     PartialEq,
@@ -31,25 +31,23 @@ pub struct DepositInput {
 impl DepositInput {
     /// Generate the 'proof_of_posession' signature for a given DepositInput details.
     ///
-    /// Spec v0.4.0
+    /// Spec v0.5.0
     pub fn create_proof_of_possession(
-        keypair: &Keypair,
-        withdrawal_credentials: &Hash256,
-        domain: u64,
+        &self,
+        secret_key: &SecretKey,
+        epoch: Epoch,
+        fork: &Fork,
+        spec: &ChainSpec,
     ) -> Signature {
-        let signable_deposit_input = DepositInput {
-            pubkey: keypair.pk.clone(),
-            withdrawal_credentials: withdrawal_credentials.clone(),
-            proof_of_possession: Signature::empty_signature(),
-        };
-        let msg = signable_deposit_input.signed_root();
+        let msg = self.signed_root();
+        let domain = spec.get_domain(epoch, Domain::Deposit, fork);
 
-        Signature::new(msg.as_slice(), domain, &keypair.sk)
+        Signature::new(msg.as_slice(), domain, secret_key)
     }
 
     /// Verify that proof-of-possession is valid.
     ///
-    /// Spec v0.4.0
+    /// Spec v0.5.0
     pub fn validate_proof_of_possession(
         &self,
         epoch: Epoch,
@@ -68,4 +66,23 @@ mod tests {
     use super::*;
 
     ssz_tests!(DepositInput);
+
+    #[test]
+    fn can_create_and_validate() {
+        let spec = ChainSpec::foundation();
+        let fork = Fork::genesis(&spec);
+        let keypair = Keypair::random();
+        let epoch = Epoch::new(0);
+
+        let mut deposit_input = DepositInput {
+            pubkey: keypair.pk.clone(),
+            withdrawal_credentials: Hash256::zero(),
+            proof_of_possession: Signature::empty_signature(),
+        };
+
+        deposit_input.proof_of_possession =
+            deposit_input.create_proof_of_possession(&keypair.sk, epoch, &fork, &spec);
+
+        assert!(deposit_input.validate_proof_of_possession(epoch, &fork, &spec));
+    }
 }
diff --git a/eth2/types/src/test_utils/testing_deposit_builder.rs b/eth2/types/src/test_utils/testing_deposit_builder.rs
index 729311468..90c8d325d 100644
--- a/eth2/types/src/test_utils/testing_deposit_builder.rs
+++ b/eth2/types/src/test_utils/testing_deposit_builder.rs
@@ -46,15 +46,18 @@ impl TestingDepositBuilder {
         );
 
         let epoch = state.current_epoch(spec);
-        let domain = spec.get_domain(epoch, Domain::Deposit, &state.fork);
 
         self.deposit.deposit_data.deposit_input.pubkey = keypair.pk.clone();
         self.deposit
             .deposit_data
             .deposit_input
             .withdrawal_credentials = withdrawal_credentials.clone();
-        self.deposit.deposit_data.deposit_input.proof_of_possession =
-            DepositInput::create_proof_of_possession(&keypair, &withdrawal_credentials, domain);
+
+        self.deposit.deposit_data.deposit_input.proof_of_possession = self
+            .deposit
+            .deposit_data
+            .deposit_input
+            .create_proof_of_possession(&keypair.sk, epoch, &state.fork, spec);
     }
 
     /// Builds the deposit, consuming the builder.