Merge pull request #2078 from rsksmart/fix-eth-filter-methods

Add filterNotFound exception to RskJsonRpcRequestException class

rskj-core/src/main/java/org/ethereum/rpc/FilterManager.java

@@ -18,6 +18,7 @@
 
 package org.ethereum.rpc;
 
+import static org.ethereum.rpc.exception.RskJsonRpcRequestException.filterNotFound;
 import org.ethereum.core.Block;
 import org.ethereum.core.Transaction;
 import org.ethereum.core.TransactionReceipt;
@@ -82,7 +83,7 @@ public Object[] getFilterEvents(int id, boolean newevents) {
             Filter filter = installedFilters.get(id);
 
             if (filter == null) {
-                return null;
+                throw filterNotFound("filter not found");
             }
 
             if (newevents) {

rskj-core/src/main/java/org/ethereum/rpc/exception/RskJsonRpcRequestException.java

@@ -57,4 +57,8 @@ public static RskJsonRpcRequestException blockNotFound(String message) {
     public static RskJsonRpcRequestException stateNotFound(String message) {
         return new RskJsonRpcRequestException(-32600, message);
     }
+
+    public static RskJsonRpcRequestException filterNotFound(String message) {
+        return new RskJsonRpcRequestException(-32000, message);
+    }
 }

rskj-core/src/test/java/org/ethereum/rpc/FilterManagerTest.java

@@ -0,0 +1,21 @@
+package org.ethereum.rpc;
+
+import org.ethereum.facade.Ethereum;
+import org.ethereum.rpc.exception.RskJsonRpcRequestException;
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Test;
+
+public class FilterManagerTest {
+
+    @Test
+    void whenGetFilterEvent_throwFilterNotFoundException() {
+        Ethereum ethMock = Web3Mocks.getMockEthereum();
+        FilterManager filterManager = new FilterManager(ethMock);
+
+        Assertions.assertThrowsExactly(
+                RskJsonRpcRequestException.class,
+                () -> filterManager.getFilterEvents(1, false),
+                "filter not found"
+        );
+    }
+}