### Question:
ExpandableUrl { public static String unifySlashes(String dir){ dir = dir.replaceAll("\\\\", "/"); if(isOsWindows() && !dir.startsWith("file") && dir.length() > 0 && dir.charAt(0) != '/' && dir.charAt(0) != '$' ){ dir = "/" + dir; } return dir; } private  ExpandableUrl(String s); static ExpandableUrl createFromPath(String path); static ExpandableUrl createFromStringUrl(String url); static String unifySlashes(String dir); static boolean isOsWindows(); URL getExpandedURL(); String getRawURL(); String getExpandedPath(); String getRawPath(); File getFile(); @Override String toString();  }### Answer:
@Test @EnabledOnOs(OS.WINDOWS) void testUnifySlashesOnWindows(){ assertEquals("/path", unifySlashes("path")); assertEquals("/path", unifySlashes("/path")); assertEquals("/longer/path", unifySlashes("longer/path")); assertEquals("/longer/path", unifySlashes("longer\\path")); assertEquals("/longer/path", unifySlashes("/longer/path")); assertEquals("/longer/path", unifySlashes("/longer\\path")); }
@Test @EnabledOnOs(OS.LINUX) void testUnifySlashesOnLinux(){ assertEquals("path", unifySlashes("path")); assertEquals("/path", unifySlashes("/path")); assertEquals("longer/path", unifySlashes("longer/path")); assertEquals("longer/path", unifySlashes("longer\\path")); assertEquals("/longer/path", unifySlashes("/longer/path")); assertEquals("/longer/path", unifySlashes("/longer\\path")); }