Writes bulk of VSR property logic

tests/difference/core/model/src/properties.ts

@@ -182,6 +182,53 @@ function stakingWithoutSlashing(hist: BlockHistory): boolean {
   return true;
 }
 
+/**
+ * Checks the validator set replication property as defined
+ * https://github.com/cosmos/ibc/blob/main/spec/app/ics-028-cross-chain-validation/system_model_and_properties.md#system-properties
+ *
+ * @param hist A history of blocks.
+ * @returns Is the property satisfied?
+ */
+function validatorSetReplication(hist: BlockHistory): boolean {
+  const blocks = hist.blocks;
+  let good = true;
+  blocks[C].forEach((b: CommittedBlock) => {
+    const ss = b.invariantSnapshot;
+    if (ss.h[C] === 0) {
+      return
+    }
+    // Get the vscid of the last update which dictated
+    // the consumer valset valsetC committed at hC-1
+    const vscid = ss.hToVscID[ss.h[C]];
+    // The VSU packet was sent at height hP-1
+    const hP = ss.vscIDtoH[vscid];
+    // Compare the validator sets at hC-1 and hP-1
+    const valsetC = blocks[C].get(ss.h[C] - 1)!.invariantSnapshot.consumerPower;
+    // The provider set is implicitly defined by the status and tokens (power)
+    console.log(`hP: ${hP}`);
+    const statusP = blocks[P].get(hP - 1)!.invariantSnapshot.status;
+    const tokensP = blocks[P].get(hP - 1)!.invariantSnapshot.tokens;
+    assert(valsetC.length === statusP.length, 'this should never happen.');
+    assert(valsetC.length === tokensP.length, 'this should never happen.');
+    valsetC.forEach((power, i) => {
+      if (power !== undefined) { // undefined means the validator is not in the set
+        good = good && tokensP[i] === power;
+      }
+    })
+    statusP.forEach((status, i) => {
+      if (status === Status.BONDED) {
+        const power = tokensP[i];
+        good = good && valsetC[i] === power;
+      }
+      else {
+        good = good && valsetC[i] === undefined;
+      }
+    })
+
+  })
+  return good;
+}
+
 /**
  * Checks the bond-based consumer voting power property as defined
  * in https://github.com/cosmos/ibc/blob/main/spec/app/ics-028-cross-chain-validation/system_model_and_properties.md#system-properties
@@ -277,4 +324,5 @@ export {
   BlockHistory,
   stakingWithoutSlashing,
   bondBasedConsumerVotingPower,
+  validatorSetReplication,
 };