diff --git a/src/main/java/com/google/devtools/build/skyframe/DepFingerprintList.java b/src/main/java/com/google/devtools/build/skyframe/DepFingerprintList.java
index 4a7fbf4..e637954 100644
--- a/src/main/java/com/google/devtools/build/skyframe/DepFingerprintList.java
+++ b/src/main/java/com/google/devtools/build/skyframe/DepFingerprintList.java
@@ -17,6 +17,7 @@
 import com.google.common.base.Preconditions;
 import com.google.common.collect.Iterators;
 import java.math.BigInteger;
+import java.util.Arrays;
 import java.util.Iterator;
 import javax.annotation.Nullable;
 
@@ -55,6 +56,11 @@
     return Iterators.forArray(fingerprints);
   }
 
+  @Override
+  public String toString() {
+    return "DepFingerprintList{" + Arrays.toString(fingerprints) + "}";
+  }
+
   private static class NoDepGroupsFingerprintMarker extends DepFingerprintList {
     private NoDepGroupsFingerprintMarker() {
       super(null);
@@ -69,6 +75,11 @@
     public Iterator<BigInteger> iterator() {
       throw new UnsupportedOperationException("No dep groups fingerprint");
     }
+
+    @Override
+    public String toString() {
+      return "NoDepGroupsFingerprintMarker";
+    }
   }
 
   /** Builder for {@code DepFingerprintList}. */