diff --git a/moshi/src/test/java/com/squareup/moshi/JsonReaderFactory.java b/moshi/src/test/java/com/squareup/moshi/JsonReaderFactory.java
index 21db1c5..8b2cc46 100644
--- a/moshi/src/test/java/com/squareup/moshi/JsonReaderFactory.java
+++ b/moshi/src/test/java/com/squareup/moshi/JsonReaderFactory.java
@@ -26,6 +26,10 @@ abstract class JsonReaderFactory {
       Buffer buffer = new Buffer().writeUtf8(json);
       return JsonReader.of(buffer);
     }
+
+    @Override public String toString() {
+      return "BufferedSourceJsonReader";
+    }
   };
 
   public static final JsonReaderFactory JSON_OBJECT = new JsonReaderFactory() {
@@ -34,6 +38,10 @@ abstract class JsonReaderFactory {
       Object object = moshi.adapter(Object.class).lenient().fromJson(json);
       return new ObjectJsonReader(object);
     }
+
+    @Override public String toString() {
+      return "ObjectJsonReader";
+    }
   };
 
   static List<Object[]> factories() {