Class CollectorTester<T,​A,​R>


  • @Beta
    @GwtCompatible
    public final class CollectorTester<T,​A,​R>
    extends Object
    Tester for Collector implementations.

    Example usage:

     CollectorTester.of(Collectors.summingInt(Integer::parseInt))
         .expectCollects(3, "1", "2")
         .expectCollects(10, "1", "4", "3", "2")
         .expectCollects(5, "-3", "0", "8");
     
    Since:
    21.0
    Author:
    Louis Wasserman
    • Method Detail

      • of

        public static <T,​A,​R> CollectorTester<T,​A,​R> of​(Collector<T,​A,​R> collector)
        Creates a CollectorTester for the specified Collector. The result of the Collector will be compared to the expected value using Object.equals.
      • of

        public static <T,​A,​R> CollectorTester<T,​A,​R> of​(Collector<T,​A,​R> collector,
                                                                                BiPredicate<? super R,​? super R> equivalence)
        Creates a CollectorTester for the specified Collector. The result of the Collector will be compared to the expected value using the specified equivalence.
      • expectCollects

        @SafeVarargs
        public final CollectorTester<T,​A,​RexpectCollects​(@Nullable R expectedResult,
                                                                       T... inputs)
        Verifies that the specified expected result is always produced by collecting the specified inputs, regardless of how the elements are divided.