Add registered call

contracts/NodesV2.sol

@@ -70,6 +70,14 @@ contract NodesV2
     inactiveNodeIndex[msg.sender] = inactiveNodes.length;
   }
 
+  function registered(bytes memory publicKey)
+  public
+  view
+  returns (bool) {
+    address node = publicKeyToAddress(publicKey);
+    return !(activeNodeIndex[node] == 0 && inactiveNodeIndex[node] == 0);
+  }
+
  function activeNodeCount() public view returns (uint) {
     return activeNodes.length;
   }

test/TestNodesV2.js

@@ -124,6 +124,22 @@ contract('Nodes', async (accounts) => {
     });
   });
 
+  describe('registered', async () => {
+    beforeEach(async () => {
+      await instance.registerNode(node1.pk, node1.ip, node1.port);
+    });
+
+    it('it returns true when node is registered', async () => {
+      const response = await instance.registered(node1.pk);
+      assert.equal(true, response);
+    });
+
+    it('it returns true when node is registered', async () => {
+      const response = await instance.registered(node2.pk);
+      assert.equal(false, response);
+    });
+  });
+
   describe('vote', async () => {
     describe('first round of voting', async () => {
       // Node1, Node2 and Node3 are active, Node4 is inactive