Index: trunk/test/unit/org/openstreetmap/josm/TestUtils.java
===================================================================
--- trunk/test/unit/org/openstreetmap/josm/TestUtils.java	(revision 18561)
+++ trunk/test/unit/org/openstreetmap/josm/TestUtils.java	(revision 18562)
@@ -602,5 +602,5 @@
      */
     public static void assertEqualsNewline(String expected, String actual) {
-        String[] actualArray = actual.split(System.lineSeparator(), -1);
+        String[] actualArray = actual.replace(System.lineSeparator(), "\n").split("\n", -1);
         String[] expectedArray = expected.split("\n", -1);
         assertAll(() -> assertEquals(expectedArray.length, actualArray.length, "Different number of newlines"),