chore(rln-relay-v2): add tests for serde (#2421)

* chore(rln-relay-v2): add tests for serde

* fix: call isOk fn instead of prop access

Co-authored-by: Ivan FB <128452529+Ivansete-status@users.noreply.github.com>

* fix: make cast more explicit

---------

Co-authored-by: Ivan FB <128452529+Ivansete-status@users.noreply.github.com>

tests/waku_rln_relay/rln_v2/test_rln_relay_v2_serde.nim

@@ -0,0 +1,90 @@
+{.used.}
+
+when (NimMajor, NimMinor) < (1, 4):
+  {.push raises: [Defect].}
+else:
+  {.push raises: [].}
+
+import 
+  ../rln/waku_rln_relay_utils,
+  ../../../waku/waku_keystore/protocol_types,
+  ../../../waku/waku_rln_relay,
+  ../../../waku/waku_rln_relay/rln
+
+import
+  testutils/unittests
+import 
+  stew/results,
+  stint
+from std/times import epochTime
+
+func fromStrToBytesLe(v: string): seq[byte] =
+  try:
+    return @(hexToUint[256](v).toBytesLE())
+  except ValueError:
+    # this should never happen
+    return @[]
+
+func defaultIdentityCredential*(): IdentityCredential =
+  # zero out the values we don't need
+  return IdentityCredential(
+    idTrapdoor: default(IdentityTrapdoor), 
+    idNullifier: default(IdentityNullifier), 
+    idSecretHash: fromStrToBytesLe("7984f7c054ad7793d9f31a1e9f29eaa8d05966511e546bced89961eb8874ab9"), 
+    idCommitment: fromStrToBytesLe("51c31de3bff7e52dc7b2eb34fc96813bacf38bde92d27fe326ce5d8296322a7")
+  )
+
+func defaultRateCommitment*(): RateCommitment =
+  let idCredential = defaultIdentityCredential()
+  return RateCommitment(
+      idCommitment: idCredential.idCommitment,
+      userMessageLimit: 100
+  )
+
+suite "RLN Relay v2: serde":
+  test "toLeaf: converts a rateCommitment to a valid leaf":
+    # this test vector is from zerokit
+    let rateCommitment = defaultRateCommitment()
+
+    let leafRes = toLeaf(rateCommitment)
+    assert leafRes.isOk(), $leafRes.error
+
+    let expectedLeaf = "09beac7784abfadc9958b3176b352389d0b969ccc7f8bccf3e968ed632e26eca"
+    check expectedLeaf == leafRes.value.inHex()
+
+
+  test "proofGen: generates a valid zk proof":
+    # this test vector is from zerokit
+    let rlnInstance = createRLNInstanceWrapper()
+    assert rlnInstance.isOk, $rlnInstance.error
+    let rln = rlnInstance.value
+
+    let credential = defaultIdentityCredential()
+    let rateCommitment = defaultRateCommitment()
+    let success = rln.insertMember(@(rateCommitment.toLeaf().value))
+    let merkleRootRes = rln.getMerkleRoot()
+    assert merkleRootRes.isOk, $merkleRootRes.error
+    let merkleRoot = merkleRootRes.value
+
+    assert success, "failed to insert member"
+
+    let proofRes = rln.proofGen(data = @[],
+                                membership = credential,
+                                userMessageLimit = rateCommitment.userMessageLimit,
+                                messageId = 0,
+                                index = 0,
+                                epoch = calcEpoch(epochTime()))
+
+    assert proofRes.isOk, $proofRes.error
+
+    let proof = proofRes.value
+
+    let proofVerifyRes = rln.proofVerify(data = @[],
+                                         proof = proof,
+                                         validRoots = @[merkleRoot])
+
+    assert proofVerifyRes.isOk, $proofVerifyRes.error
+    assert proofVerifyRes.value, "proof verification failed"
+
+
+

waku/waku_rln_relay/conversion_utils.nim

@@ -57,6 +57,17 @@ proc encodeLengthPrefix*(input: openArray[byte]): seq[byte] =
     output = concat(@len, @input)
   return output
 
+proc serialize*(v: uint64): array[32, byte] =
+  ## a private proc to convert uint64 to a byte seq
+  ## this conversion is used in the proofGen proc
+
+  ## converts `v` to a byte seq in little-endian order
+  let bytes = toBytes(v, Endianness.littleEndian)
+  var output: array[32, byte]
+  discard output.copyFrom(bytes)
+  return output
+
+
 when defined(rln_v2):
   proc serialize*(idSecretHash: IdentitySecretHash, 
                   memIndex: MembershipIndex, 
@@ -69,8 +80,8 @@ when defined(rln_v2):
     ## the serialization is done as instructed in  https://github.com/kilic/rln/blob/7ac74183f8b69b399e3bc96c1ae8ab61c026dc43/src/public.rs#L146
     ## [ id_key<32> | id_index<8> | epoch<32> | signal_len<8> | signal<var> ]
     let memIndexBytes = toBytes(uint64(memIndex), Endianness.littleEndian)
-    let userMessageLimitBytes = toBytes(uint64(userMessageLimit), Endianness.littleEndian)
-    let messageIdBytes = toBytes(uint64(messageId), Endianness.littleEndian)
+    let userMessageLimitBytes = userMessageLimit.serialize()
+    let messageIdBytes = messageId.serialize()
     let lenPrefMsg = encodeLengthPrefix(msg)
     let output = concat(@idSecretHash, @memIndexBytes, @userMessageLimitBytes, @messageIdBytes, @externalNullifier, lenPrefMsg)
     return output

waku/waku_rln_relay/rln/wrappers.nim

@@ -163,8 +163,8 @@ proc poseidon*(data: seq[seq[byte]]): RlnRelayResult[array[32, byte]] =
 when defined(rln_v2):
   func toLeaf*(rateCommitment: RateCommitment): RlnRelayResult[MerkleNode] {.inline.} =
     let idCommitment = rateCommitment.idCommitment
-    let userMessageLimit = rateCommitment.userMessageLimit
-    let leafRes = poseidon(@[@idCommitment, cast[seq[byte]](userMessageLimit)])
+    let userMessageLimit =  cast[array[32, byte]](rateCommitment.userMessageLimit)
+    let leafRes = poseidon(@[@idCommitment, @userMessageLimit])
     return leafRes
 
   func toLeaves*(rateCommitments: seq[RateCommitment]): RlnRelayResult[seq[MerkleNode]] {.inline.} =