Test SOCKS4 client: CONNECTION_REFUSED when connecting

core/java/test/junit/net/i2p/socks/SOCKS4ClientTest.java

@@ -87,6 +87,22 @@ public class SOCKS4ClientTest {
                 80);
         });
     }
+    /**
+     * Check that CONNECTION_REFUSED throws exception
+     */
+    @Test
+    public void connect__responseCONNECTION_REFUSED() {
+        assertThrows(SOCKSException.class, () -> {
+            SOCKS4Client.connect(new ByteArrayInputStream(new byte[]{
+                    0, // dummy
+                    SOCKS4Constants.Reply.CONNECTION_REFUSED, // Connection succeeded
+                }),
+                new ByteArrayOutputStream(),
+                "1.1.1.1",
+                80
+            );
+        });
+    }
 
     /**
      * IPv6 is not supported by this SOCKS client so it just throws an exception