diff --git a/src/test/java/org/opentripplanner/test/support/JsonAssertions.java b/src/test/java/org/opentripplanner/test/support/JsonAssertions.java
index 2dab1e96190..f57e5a6741d 100644
--- a/src/test/java/org/opentripplanner/test/support/JsonAssertions.java
+++ b/src/test/java/org/opentripplanner/test/support/JsonAssertions.java
@@ -5,12 +5,17 @@
 import com.fasterxml.jackson.core.JsonProcessingException;
 import com.fasterxml.jackson.databind.JsonNode;
 import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.databind.SerializationFeature;
 import org.opentripplanner.standalone.config.framework.json.JsonSupport;
 
 public class JsonAssertions {
 
   private static final ObjectMapper MAPPER = new ObjectMapper();
 
+  static {
+    MAPPER.configure(SerializationFeature.ORDER_MAP_ENTRIES_BY_KEYS, true);
+  }
+
   /**
    * Take two JSON documents and reformat them before comparing {@code actual} with {@code expected}.
    */