### Question:
StringUtils { public static String car(String name, String... sep) { String realSep = separator(sep); final int i = name.indexOf(realSep); if (i > 0) return name.substring(0, i); else return name; }  static String arrayFormat(String format, Object[] items); static Optional<String> cdr(String name, String... sep); static String car(String name, String... sep); static String lastOf(String qualifiedName, String... sep); static String untill(String qualifiedName, String... sep); static String dotToUpperCamelCase(String input); static String dotToDash(String input); static String camelCaseToDash(String input); static boolean isPackageFriendly(String moduleName); static String withoutTypeArgs(String javaTypeString); static String notEmptytrimmed(String param); static Optional<Tuple<String, String>> splitIntoTwo(String mappingString); static int countMatches(String theString, String... sep);  }### Answer:
@Test void tesrCarOfString() { assertEquals("de", car("de.dz")); assertEquals("de", car("de")); assertEquals("", car("")); assertEquals("a", car("a.b.c.d")); }