### Question:
NullaryFunctionFunction implements Function<A, T> { public static <A, T> NullaryFunctionFunction<A, T> adapt(NullaryFunction<? extends T> function) { return null == function ? null : new NullaryFunctionFunction<A, T>(function); } NullaryFunctionFunction(NullaryFunction<? extends T> function); T evaluate(A obj); @Override boolean equals(Object obj); @Override int hashCode(); @Override String toString(); static NullaryFunctionFunction<A, T> adapt(NullaryFunction<? extends T> function);  }### Answer:
@Test public void testAdaptNull() throws Exception { assertNull(NullaryFunctionFunction.adapt(null)); }
@Test public void testAdapt() throws Exception { assertNotNull(NullaryFunctionFunction.adapt(Constant.of("xyzzy"))); }