Add unit tests for the retarget at block 720.

src/main/java/org/libdohj/params/AbstractDogecoinParams.java

@@ -20,7 +20,6 @@ import java.io.ByteArrayOutputStream;
 import java.math.BigInteger;
 import org.bitcoinj.core.AltcoinBlock;
 
-import org.libdohj.core.AltcoinNetworkParameters;
 import org.bitcoinj.core.Block;
 import org.bitcoinj.core.Coin;
 import static org.bitcoinj.core.Coin.COIN;
@@ -92,6 +91,8 @@ public abstract class AbstractDogecoinParams extends NetworkParameters implement
     protected final int diffChangeTarget;
 
     protected Logger log = LoggerFactory.getLogger(AbstractDogecoinParams.class);
+    public static final int DOGECOIN_PROTOCOL_VERSION_AUXPOW = 70003;
+    public static final int DOGECOIN_PROTOCOL_VERSION_CURRENT = 70004;
 
     public AbstractDogecoinParams(final int setDiffChangeTarget) {
         super();
@@ -320,6 +321,20 @@ public abstract class AbstractDogecoinParams extends NetworkParameters implement
         return new AltcoinSerializer(this, parseRetain);
     }
 
+    @Override
+    public int getProtocolVersionNum(final ProtocolVersion version) {
+        switch (version) {
+            case PONG:
+            case BLOOM_FILTER:
+                return version.getBitcoinProtocolVersion();
+            case CURRENT:
+                return DOGECOIN_PROTOCOL_VERSION_CURRENT;
+            case MINIMUM:
+            default:
+                return DOGECOIN_PROTOCOL_VERSION_AUXPOW;
+        }
+    }
+
     @Override
     public boolean isAuxPoWBlockVersion(long version) {
         return version >= BLOCK_MIN_VERSION_AUXPOW

src/test/java/org/libdohj/params/AbstractDogecoinParamsTest.java

@@ -43,14 +43,28 @@ public class AbstractDogecoinParamsTest {
         long lastRetargetDifficulty = 0x1e0ffff0;
         long lastRetargetTime = 1386474927; // Block 1
         long newDifficulty = params.getNewDifficultyTarget(previousHeight, previousBlockTime, lastRetargetDifficulty, lastRetargetTime);
-        assertEquals(newDifficulty, 0x1e00ffff);
+        assertEquals(0x1e00ffff, newDifficulty);
 
         previousHeight = 9599;
         previousBlockTime = 1386954113;
         lastRetargetDifficulty = 0x1c1a1206;
         lastRetargetTime = 1386942008; // Block 9359
         newDifficulty = params.getNewDifficultyTarget(previousHeight, previousBlockTime, lastRetargetDifficulty, lastRetargetTime);
-        assertEquals(newDifficulty, 0x1c15ea59);
+        assertEquals(0x1c15ea59, newDifficulty);
+    }
+
+    /**
+     * Test block 720, where the time interval is below the minimum time interval
+     * (900 seconds).
+     */
+    @Test
+    public void shouldConstrainActualTime() {
+        int previousHeight = 719;
+        long previousBlockTime = 1386476362; // Block 719
+        long lastRetargetDifficulty = 0x1e00ffff;
+        long lastRetargetTime = 1386475840; // Block 439
+        long newDifficulty = params.getNewDifficultyTarget(previousHeight, previousBlockTime, lastRetargetDifficulty, lastRetargetTime);
+        assertEquals(0x1d0ffff0, newDifficulty);
     }
 
     @Test
@@ -60,7 +74,7 @@ public class AbstractDogecoinParamsTest {
         long lastRetargetDifficulty = 0x1b499dfd;
         long lastRetargetTime = 1395094427;
         long newDifficulty = params.getNewDifficultyTarget(previousHeight, previousBlockTime, lastRetargetDifficulty, lastRetargetTime);
-        assertEquals(newDifficulty, 0x1b671062);
+        assertEquals(0x1b671062, newDifficulty);
     }
 
     @Test
@@ -71,20 +85,25 @@ public class AbstractDogecoinParamsTest {
         long lastRetargetDifficulty = 0x1b671062;
         long lastRetargetTime = 1395094679;
         long newDifficulty = params.getNewDifficultyTarget(previousHeight, previousBlockTime, lastRetargetDifficulty, lastRetargetTime);
-        assertEquals(newDifficulty, 0x1b6558a4);
+        assertEquals(0x1b6558a4, newDifficulty);
     }
 
     @Test
-    public void shouldCalculateFirstRetarget() throws IOException {
+    public void shouldCalculateRetarget() throws IOException {
         // Do a more in-depth test for the first retarget
         byte[] payload = Util.getBytes(getClass().getResourceAsStream("dogecoin_block239.bin"));
         AltcoinSerializer serializer = (AltcoinSerializer)params.getDefaultSerializer();
         final AltcoinBlock block239 = (AltcoinBlock)serializer.makeBlock(payload);
         final AltcoinBlock block479;
+        final AltcoinBlock block719;
 
         payload = Util.getBytes(getClass().getResourceAsStream("dogecoin_block479.bin"));
         block479 = (AltcoinBlock)serializer.makeBlock(payload);
 
+        payload = Util.getBytes(getClass().getResourceAsStream("dogecoin_block719.bin"));
+        block719 = (AltcoinBlock)serializer.makeBlock(payload);
+
         assertEquals(0x1e00ffff, params.getNewDifficultyTarget(479, block239, block479));
+        assertEquals(0x1d0ffff0, params.getNewDifficultyTarget(719, block479, block719));
     }
 }