diff --git a/aws-serverless-java-container-core/src/test/java/com/amazonaws/serverless/proxy/model/CognitoAuthorizerClaimsTest.java b/aws-serverless-java-container-core/src/test/java/com/amazonaws/serverless/proxy/model/CognitoAuthorizerClaimsTest.java
index 1805edf30..de8b36547 100644
--- a/aws-serverless-java-container-core/src/test/java/com/amazonaws/serverless/proxy/model/CognitoAuthorizerClaimsTest.java
+++ b/aws-serverless-java-container-core/src/test/java/com/amazonaws/serverless/proxy/model/CognitoAuthorizerClaimsTest.java
@@ -7,6 +7,7 @@
 import java.io.IOException;
 import java.time.ZonedDateTime;
 import java.time.format.DateTimeFormatter;
+import java.util.Locale;
 
 import static org.junit.Assert.*;
 
@@ -19,7 +20,7 @@ public class CognitoAuthorizerClaimsTest {
 
     private static final String EXP_TIME = "Mon Apr 17 23:12:49 UTC 2017";
     private static final String ISSUE_TIME = "Mon Apr 17 22:12:49 UTC 2017";
-    static final DateTimeFormatter TOKEN_DATE_FORMATTER = DateTimeFormatter.ofPattern("EEE MMM dd HH:mm:ss zzz yyyy");
+    static final DateTimeFormatter TOKEN_DATE_FORMATTER = DateTimeFormatter.ofPattern("EEE MMM dd HH:mm:ss zzz yyyy").withLocale(Locale.ENGLISH);
 
     private static final String USER_POOLS_REQUEST = "{\n"
                                                      + "    \"resource\": \"/restaurants\",\n"