2 files changed, 28 insertions, 0 deletions
diff --git a/poi/src/test/java/org/apache/poi/ss/formula/functions/TestDays.java b/poi/src/test/java/org/apache/poi/ss/formula/functions/TestDays.java
index c3b804995a..fab91e1fd0 100644
--- a/poi/src/test/java/org/apache/poi/ss/formula/functions/TestDays.java
+++ b/poi/src/test/java/org/apache/poi/ss/formula/functions/TestDays.java
@@ -23,10 +23,14 @@ import org.apache.poi.hssf.usermodel.HSSFSheet;
 import org.apache.poi.hssf.usermodel.HSSFWorkbook;
 import org.apache.poi.ss.usermodel.DateUtil;
 import org.apache.poi.ss.usermodel.FormulaError;
+import org.apache.poi.util.LocaleUtil;
+import org.junit.jupiter.api.AfterAll;
+import org.junit.jupiter.api.BeforeAll;
 import org.junit.jupiter.api.Test;
 
 import java.io.IOException;
 import java.time.LocalDate;
+import java.util.Locale;
 
 import static org.apache.poi.ss.util.Utils.addRow;
 import static org.apache.poi.ss.util.Utils.assertDouble;
@@ -37,6 +41,16 @@ import static org.apache.poi.ss.util.Utils.assertError;
  */
 public class TestDays {
 
+    @BeforeAll
+    static void setUp() {
+        LocaleUtil.setUserLocale(Locale.US);
+    }
+
+    @AfterAll
+    static void tearDown() {
+        LocaleUtil.setUserLocale(null);
+    }
+
     //https://support.microsoft.com/en-us/office/days-function-57740535-d549-4395-8728-0f07bff0b9df
     @Test
     void testMicrosoftExample1() throws IOException {
diff --git a/poi/src/test/java/org/apache/poi/ss/usermodel/BaseTestDataFormat.java b/poi/src/test/java/org/apache/poi/ss/usermodel/BaseTestDataFormat.java
index 65ee8ffa49..eed2fd3cc3 100644
--- a/poi/src/test/java/org/apache/poi/ss/usermodel/BaseTestDataFormat.java
+++ b/poi/src/test/java/org/apache/poi/ss/usermodel/BaseTestDataFormat.java
@@ -22,8 +22,12 @@ import static org.junit.jupiter.api.Assertions.assertNotNull;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import java.io.IOException;
+import java.util.Locale;
 
 import org.apache.poi.ss.ITestDataProvider;
+import org.apache.poi.util.LocaleUtil;
+import org.junit.jupiter.api.AfterAll;
+import org.junit.jupiter.api.BeforeAll;
 import org.junit.jupiter.api.Test;
 
 /**
@@ -45,6 +49,16 @@ public abstract class BaseTestDataFormat {
         assertEquals(-1, BuiltinFormats.getBuiltinFormat(customFmt));
     }
 
+    @BeforeAll
+    static void setUp() {
+        LocaleUtil.setUserLocale(Locale.US);
+    }
+
+    @AfterAll
+    static void tearDown() {
+        LocaleUtil.setUserLocale(null);
+    }
+
     @Test
     public final void testBuiltinFormats() throws IOException {
         try (Workbook wb = _testDataProvider.createWorkbook()) {