### Question:
StringUtil { public static String padding(int width) { if (width < 0) throw new IllegalArgumentException("width must be > 0"); if (width < padding.length) return padding[width]; char[] out = new char[width]; for (int i = 0; i < width; i++) out[i] = ' '; return String.valueOf(out); }  static String join(Collection strings, String sep); static String join(Iterator strings, String sep); static String padding(int width); static boolean isBlank(String string); static boolean isNumeric(String string); static String normaliseWhitespace(String string); static boolean in(String needle, String... haystack);  }### Answer:
@Test public void padding() { assertEquals("", StringUtil.padding(0)); assertEquals(" ", StringUtil.padding(1)); assertEquals(" ", StringUtil.padding(2)); assertEquals(" ", StringUtil.padding(15)); }