for (int i = 0; i < iterations; i++) {
        int keyIndex = random.nextInt(nKeys);
        String key = keys.get(keyIndex);
        Operation op = operations[random.nextInt(operations.length)];
        switch (op) {
          case ADD:
            {
              int delta = random.nextInt(10);
              multiset.add(key, delta);
              deltas[keyIndex] += delta;
              break;

        double num = RANDOM.nextInt(10);
        for (int i = 0; i < num; i++) {
          list.add((double) counter.getAndIncrement());
        }
        builder.addAll(iterable(list));
      }
    },
    ADD_STREAM {
      @Override
      void doIt(ImmutableDoubleArray.Builder builder, AtomicInteger counter) {
        double[] array = new double[RANDOM.nextInt(10)];

    for (int i = 0; i < heapSize; i++) {
      mmHeap.add(random.nextInt());
    }
    for (int i = 0; i < numberOfModifications; i++) {
      mmHeap.removeAt(random.nextInt(mmHeap.size()));
      assertIntactUsingSeed(seed, mmHeap);
      mmHeap.add(random.nextInt());
      assertIntactUsingSeed(seed, mmHeap);
    }
  }

  public void testRemoveAt_exhaustive() {

        int num = RANDOM.nextInt(10);
        for (int i = 0; i < num; i++) {
          list.add(counter.getAndIncrement());
        }
        builder.addAll(iterable(list));
      }
    },
    ADD_STREAM {
      @Override
      void doIt(ImmutableIntArray.Builder builder, AtomicInteger counter) {
        int[] array = new int[RANDOM.nextInt(10)];
        for (int i = 0; i < array.length; i++) {

        double num = RANDOM.nextInt(10);
        for (int i = 0; i < num; i++) {
          list.add((double) counter.getAndIncrement());
        }
        builder.addAll(iterable(list));
      }
    },
    ADD_STREAM {
      @Override
      void doIt(ImmutableDoubleArray.Builder builder, AtomicInteger counter) {
        double[] array = new double[RANDOM.nextInt(10)];

    for (int i = 0; i < heapSize; i++) {
      mmHeap.add(random.nextInt());
    }
    for (int i = 0; i < numberOfModifications; i++) {
      mmHeap.removeAt(random.nextInt(mmHeap.size()));
      assertIntactUsingSeed(seed, mmHeap);
      mmHeap.add(random.nextInt());
      assertIntactUsingSeed(seed, mmHeap);
    }
  }

  public void testRemoveAt_exhaustive() {

        UrlSource source = new UrlSource(txtFile);
        try (InputStream is = source.getInputStream();
                Scanner scanner = new Scanner(is)) {
            assertEquals("Hello World!", scanner.nextLine());
        }
    }

    @Test
    void testGetLocation() throws Exception {
        URL txtFile = new File("target/test-classes/source.txt").toURI().toURL();
        UrlSource source = new UrlSource(txtFile);

        FileSource source = new FileSource(txtFile);

        try (InputStream is = source.getInputStream();
                Scanner scanner = new Scanner(is)) {

            assertEquals("Hello World!", scanner.nextLine());
        }
    }

    @Test
    void testGetLocation() {
        File txtFile = new File("target/test-classes/source.txt");
        FileSource source = new FileSource(txtFile);

        StringSource source = new StringSource("Hello World!");

        try (InputStream is = source.getInputStream();
                Scanner scanner = new Scanner(is)) {
            assertEquals("Hello World!", scanner.nextLine());
        }
    }

    @Test
    void testGetLocation() {
        StringSource source = new StringSource("Hello World!");
        assertEquals("(memory)", source.getLocation());

  void setUp() {
    checkArgument(size > 0, "empty collection not supported");
    Set<Integer> set = new LinkedHashSet<>(size);

    Random random = new Random();
    while (set.size() < size) {
      set.add(random.nextInt());
    }
    List<Integer> list = new ArrayList<>(set);
    inputOrder.arrange(list);
    input = ImmutableList.copyOf(list);
  }

  @Benchmark
  int collections(int reps) {
    int dummy = 0;