diff --git a/core/src/main/java/org/bitcoinj/core/NetworkParameters.java b/core/src/main/java/org/bitcoinj/core/NetworkParameters.java
index a1486d0e..7db7f772 100644
--- a/core/src/main/java/org/bitcoinj/core/NetworkParameters.java
+++ b/core/src/main/java/org/bitcoinj/core/NetworkParameters.java
@@ -62,6 +62,8 @@ public abstract class NetworkParameters implements Serializable {
     public static final String PAYMENT_PROTOCOL_ID_MAINNET = "main";
     /** The string used by the payment protocol to represent the test net. */
     public static final String PAYMENT_PROTOCOL_ID_TESTNET = "test";
+    /** The string used by the payment protocol to represent unit testing (note that this is non-standard). */
+    public static final String PAYMENT_PROTOCOL_ID_UNIT_TESTS = "unittest";
 
     // TODO: Seed nodes should be here as well.
 
@@ -224,6 +226,8 @@ public abstract class NetworkParameters implements Serializable {
             return MainNetParams.get();
         } else if (pmtProtocolId.equals(PAYMENT_PROTOCOL_ID_TESTNET)) {
             return TestNet3Params.get();
+        } else if (pmtProtocolId.equals(PAYMENT_PROTOCOL_ID_UNIT_TESTS)) {
+            return UnitTestParams.get();
         } else {
             return null;
         }
diff --git a/core/src/main/java/org/bitcoinj/params/UnitTestParams.java b/core/src/main/java/org/bitcoinj/params/UnitTestParams.java
index 66696a77..41bee1ea 100644
--- a/core/src/main/java/org/bitcoinj/params/UnitTestParams.java
+++ b/core/src/main/java/org/bitcoinj/params/UnitTestParams.java
@@ -58,6 +58,6 @@ public class UnitTestParams extends NetworkParameters {
 
     @Override
     public String getPaymentProtocolId() {
-        return null;
+        return "unittest";
     }
 }