### Question:
BillingUtils { public static boolean classChildOf(Class<?> child, Class<?> parent) { return child != null && parent != null && parent.isAssignableFrom(child); } private  BillingUtils(); static Map<String, String> stringsToMap(String ... keyValues); static List<String> getResourceAsList(String resourceName); static List<Class<?>> getModuleClassList(); static boolean classChildOf(Class<?> child, Class<?> parent); static ModuleType getModuleType(Class<?> moduleClass); static String getSimpleUserName(String username);  }### Answer:
@Test public void classChildOf() { assertEquals(true, BillingUtils.classChildOf(AdapterConsole.class, AdapterBase.class)); assertEquals(false, BillingUtils.classChildOf(AdapterConsole.class, FilterBase.class)); assertEquals(true, BillingUtils.classChildOf(FilterAWS.class, FilterBase.class)); assertEquals(false, BillingUtils.classChildOf(FilterAWS.class, ParserBase.class)); assertEquals(true, BillingUtils.classChildOf(ParserCsv.class, ParserBase.class)); assertEquals(false, BillingUtils.classChildOf(ParserCsv.class, AppenderBase.class)); assertEquals(true, BillingUtils.classChildOf(AppenderConsole.class, AppenderBase.class)); assertEquals(false, BillingUtils.classChildOf(AppenderConsole.class, AdapterBase.class)); }