### Question:
StringFunctions { public StringFunctions(String value){ this.theString = value; } StringFunctions(String value); String lowerCase(); String upperCase(); String charAt(String param); String contain(String param); String compare(String param); String substring(String index1,String index2); Method getMethod(String method); Method getMethod(String method, Class<?>... param);  }### Answer:
@Test public void testStringFunctions(){ StringFunctions stringFunctions = new StringFunctions("mystring"); Assert.assertNotNull(stringFunctions.upperCase()); Assert.assertNotNull(stringFunctions.lowerCase()); Assert.assertNotNull(stringFunctions.charAt("2")); Assert.assertNotNull(stringFunctions.contain("my")); System.out.println(stringFunctions.contain("my")); Assert.assertNotNull(stringFunctions.compare("otherstring")); Assert.assertNotNull(stringFunctions.substring("3","8")); }