[PAN-2959] return the ethereum address of the privacy precompile from priv_getPrivacyPrecompileAddress (#1766)

Signed-off-by: Adrian Sutton <adrian.sutton@consensys.net>

ethereum/jsonrpc/src/main/java/tech/pegasys/pantheon/ethereum/jsonrpc/internal/methods/privacy/priv/PrivGetPrivacyPrecompileAddress.java

@@ -12,6 +12,7 @@
  */
 package tech.pegasys.pantheon.ethereum.jsonrpc.internal.methods.privacy.priv;
 
+import tech.pegasys.pantheon.ethereum.core.Address;
 import tech.pegasys.pantheon.ethereum.core.PrivacyParameters;
 import tech.pegasys.pantheon.ethereum.jsonrpc.RpcMethod;
 import tech.pegasys.pantheon.ethereum.jsonrpc.internal.JsonRpcRequest;
@@ -40,7 +41,8 @@ public class PrivGetPrivacyPrecompileAddress implements JsonRpcMethod {
   public JsonRpcResponse response(final JsonRpcRequest request) {
 
     if (privacyEnabled) {
-      return new JsonRpcSuccessResponse(request.getId(), privacyAddress);
+      return new JsonRpcSuccessResponse(
+          request.getId(), Address.privacyPrecompiled(privacyAddress).toString());
     } else {
       return new JsonRpcErrorResponse(request.getId(), JsonRpcError.PRIVACY_NOT_ENABLED);
     }

ethereum/jsonrpc/src/test/java/tech/pegasys/pantheon/ethereum/jsonrpc/internal/methods/privacy/priv/PrivGetPrivacyPrecompileAddressTest.java

@@ -16,6 +16,7 @@ import static org.junit.Assert.assertEquals;
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.when;
 
+import tech.pegasys.pantheon.ethereum.core.Address;
 import tech.pegasys.pantheon.ethereum.core.PrivacyParameters;
 import tech.pegasys.pantheon.ethereum.jsonrpc.internal.JsonRpcRequest;
 import tech.pegasys.pantheon.ethereum.jsonrpc.internal.response.JsonRpcError;
@@ -28,12 +29,13 @@ import org.junit.Test;
 
 public class PrivGetPrivacyPrecompileAddressTest {
 
-  private final Integer privacyAddress = 127;
+  private final int rawPrivacyAddress = Address.PRIVACY;
+  private final String privacyAddress = Address.privacyPrecompiled(rawPrivacyAddress).toString();
   private final PrivacyParameters privacyParameters = mock(PrivacyParameters.class);
 
   @Test
   public void verifyPrivacyPrecompileAddress() {
-    when(privacyParameters.getPrivacyAddress()).thenReturn(privacyAddress);
+    when(privacyParameters.getPrivacyAddress()).thenReturn(rawPrivacyAddress);
     when(privacyParameters.isEnabled()).thenReturn(true);
 
     final PrivGetPrivacyPrecompileAddress privGetPrivacyPrecompileAddress =
@@ -50,7 +52,7 @@ public class PrivGetPrivacyPrecompileAddressTest {
 
   @Test
   public void verifyErrorPrivacyDisabled() {
-    when(privacyParameters.getPrivacyAddress()).thenReturn(privacyAddress);
+    when(privacyParameters.getPrivacyAddress()).thenReturn(rawPrivacyAddress);
     when(privacyParameters.isEnabled()).thenReturn(false);
 
     final PrivGetPrivacyPrecompileAddress privGetPrivacyPrecompileAddress =