anchor.diff:          verify(ordering, [1, 2], [2, 1]);
           verify(ordering, [1, 2, 3], [2, 3, 1]);
           verify(ordering, [2, 3, 1], [2, 3, 1]);
  -        expect(() => ordering.binarySearch([2, 3, 1], 4), throws);
  -        expect(() => ordering.binarySearch([2, 4, 1], 3), throws);
  +        expect(() => ordering.binarySearch([2, 3, 1], 4), throwsStateError);
  +        expect(() => ordering.binarySearch([2, 4, 1], 3), throwsStateError);
         });
       });
       group('operators', () {
  
positive.code:         expect(natural.min(2, 2), 2);
        });
        test('minOf', () {
          expect(() => natural.minOf([]), throws);
          expect(natural.minOf([1]), 1);
          expect(natural.minOf([1, 2]), 1);
          expect(natural.minOf([2, 1]), 1);
  
negative.code:         expect(natural.max(2, 2), 2);
        });
        test('maxOf', () {
          expect(() => natural.maxOf([]), throwsStateError);
          expect(natural.maxOf([1]), 1);
          expect(natural.maxOf([1, 2]), 2);
          expect(natural.maxOf([2, 1]), 2);
  