/**
     * Compares the specified object with this cell for equality. Two cells are equal when they have
     * equal row keys, column keys, and values.
     */
    @Override
    boolean equals(@Nullable Object obj);

    /**
     * Returns the hash code of this cell.
     *
     * <p>The hash code of a table cell is equal to {@link Objects#hashCode}{@code (e.getRowKey(),
     * e.getColumnKey(), e.getValue())}.

        SnapshotVersion sv1 = addSnapshotVersion(source.getVersioning(), date, artifact);
        // although nothing has changed merge returns true, as the last modified date is equal
        // TODO: improve merge here?
        assertTrue(target.merge(source));
        assertEquals(1, target.getVersioning().getSnapshotVersions().size());

   *
   * <ul>
   *   <li>Its execution does not cause any observable side effects.
   *   <li>The computation is <i>consistent with equals</i>; that is, {@link Objects#equal
   *       Objects.equal}{@code (a, b)} implies that {@code predicate.apply(a) ==
   *       predicate.apply(b))}.
   * </ul>
   *
   * @throws NullPointerException if {@code input} is null and this predicate does not accept null

@J2ktIncompatible
@GwtIncompatible
public interface Interner<E> {
  /**
   * Chooses and returns the representative instance for any of a collection of instances that are
   * equal to each other. If two {@linkplain Object#equals equal} inputs are given to this method,
   * both calls will return the same instance. That is, {@code intern(a).equals(a)} always holds,

   *       instances.
   *   <li>For the constructor or static factory method used to construct instances, it's checked
   *       that when equal parameters are passed, the result instance should also be equal; and vice
   *       versa.
   *   <li>If a non-private constructor or non-private static factory method exists:
   *       <ul>

   *       instances.
   *   <li>For the constructor or static factory method used to construct instances, it's checked
   *       that when equal parameters are passed, the result instance should also be equal; and vice
   *       versa.
   *   <li>If a non-private constructor or non-private static factory method exists:
   *       <ul>

     *
     * @throws IllegalArgumentException if any two keys are equal according to the comparator (which
     *     might be the keys' natural order)
     */
    @Override
    public ImmutableSortedMap<K, V> build() {
      return buildOrThrow();
    }

    /**
     * Returns a newly-created immutable sorted map, or throws an exception if any two keys are
     * equal.
     *

   * their map views, as returned by {@link #asMap}, are also equal.
   *
   * <p>In general, two multimaps with identical key-value mappings may or may not be equal,
   * depending on the implementation. For example, two {@link SetMultimap} instances with the same
   * key-value mappings are equal, but equality of two {@link ListMultimap} instances depends on the

   *
   * <ul>
   *   <li>Its execution does not cause any observable side effects.
   *   <li>The computation is <i>consistent with equals</i>; that is, {@link Objects#equal
   *       Objects.equal}{@code (a, b)} implies that {@code predicate.apply(a) ==
   *       predicate.apply(b))}.
   * </ul>
   *
   * @throws NullPointerException if {@code input} is null and this predicate does not accept null

			t.Fatalf("test %v: result: expected: %v, got: %v", i+1, testCase.set, result)
		}

		result.add(testCase.targetIDToAdd)
		if reflect.DeepEqual(result, testCase.set) {
			t.Fatalf("test %v: result: expected: not equal, got: equal", i+1)
		}
	}
}

func TestTargetIDSetUnion(t *testing.T) {
	testCases := []struct {
		set            TargetIDSet
		setToAdd       TargetIDSet
		expectedResult TargetIDSet
	}{