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  1. import java.util.Collection;
  2. import java.util.List;
  3. import java.util.function.Supplier;
  4.  
  5. class Should {
  6.  
  7.     static void beEqual(Object expected, Object given) {
  8.         if (!expected.equals(given)) {
  9.             throw new RuntimeException("equality failed. expected " + expected + ", but given " + given);
  10.         }
  11.     }
  12. }
  13.  
  14. // ----------------------------------------------------------------
  15.  
  16. class A {
  17.  
  18.     String description(int x) {
  19.         return getClass().getSimpleName();
  20.     }
  21. }
  22.  
  23. class ASpec<T extends A> {
  24.  
  25.     final void runAll(Collection<Supplier<? extends T>> implementations) {
  26.         implementations.forEach(this::run);
  27.     }
  28.  
  29.     void run(Supplier<? extends T> a) {
  30.         should_be_A_object_description_when_x_is_42(a.get());
  31.     }
  32.  
  33.     String descriptionOf(A a) {
  34.         return a.getClass().getSimpleName();
  35.     }
  36.  
  37.     void should_be_A_object_description_when_x_is_42(A a) {
  38.         final var expected = descriptionOf(a);
  39.         Should.beEqual(expected, a.description(42));
  40.     }
  41. }
  42.  
  43. class B extends A {
  44.  
  45.     String description() {
  46.         return "B";
  47.     }
  48. }
  49.  
  50. class BSpec<T extends B> extends ASpec<B> {
  51.  
  52.     void run(Supplier<? extends B> b) {
  53.         super.run(b);
  54.         should_be_B_object_description(b.get());
  55.     }
  56.  
  57.     String bDescriptionOf(B b) {
  58.         return "B";
  59.     }
  60.  
  61.     void should_be_B_object_description(B b) {
  62.         final var expected = bDescriptionOf(b);
  63.         Should.beEqual(expected, b.description());
  64.     }
  65. }
  66.  
  67. final class Ideone {
  68.  
  69.     public static void main(String[] args) {
  70.         new ASpec<>().runAll(List.of(A::new, B::new));
  71.         new BSpec<>().runAll(List.of(B::new));
  72.     }
  73. }
Success #stdin #stdout 0.07s 33812KB
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https://ideone.com/zuuxfP
language:
Java (HotSpot 12)
created:
4 years ago
visibility:
public

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