diff --git a/src/ol/structs/integerset.js b/src/ol/structs/integerset.js
new file mode 100644
index 0000000000..bdccb8e854
--- /dev/null
+++ b/src/ol/structs/integerset.js
@@ -0,0 +1,333 @@
+// FIXME refactor to use a packed array of integers to reduce GC load
+
+goog.provide('ol.structs.IntegerRange');
+goog.provide('ol.structs.IntegerSet');
+
+goog.require('goog.array');
+goog.require('goog.asserts');
+
+
+/**
+ * @typedef {{start: number, stop: number}}
+ */
+ol.structs.IntegerRange;
+
+
+/**
+ * @param {ol.structs.IntegerRange} range1 Range 1.
+ * @param {ol.structs.IntegerRange} range2 Range 2.
+ * @return {number} Compare.
+ */
+ol.structs.IntegerRange.compare = function(range1, range2) {
+  return range1.start - range2.start || range1.stop - range2.stop;
+};
+
+
+
+/**
+ * A set of integers represented as a set of integer ranges.
+ * This implementation is designed for the case when the number of distinct
+ * integer ranges is small.
+ * @constructor
+ * @param {Array.<ol.structs.IntegerRange>=} opt_ranges Ranges.
+ */
+ol.structs.IntegerSet = function(opt_ranges) {
+
+  /**
+   * @private
+   * @type {Array.<number>}
+   */
+  this.ranges_ = goog.isDef(opt_ranges) ? opt_ranges : [];
+
+  if (goog.DEBUG) {
+    this.assertValid();
+  }
+
+};
+
+
+/**
+ * @param {Array.<number>} arr Array.
+ * @return {ol.structs.IntegerSet} Integer set.
+ */
+ol.structs.IntegerSet.unpack = function(arr) {
+  var n = arr.length;
+  goog.asserts.assert(n % 2 === 0);
+  var ranges = new Array(n / 2);
+  var rangeIndex = 0;
+  var i;
+  for (i = 0; i < n; i += 2) {
+    ranges[rangeIndex++] = {
+      start: arr[i],
+      stop: arr[i + 1]
+    };
+  }
+  return new ol.structs.IntegerSet(ranges);
+};
+
+
+/**
+ * @param {number} addStart Start.
+ * @param {number} addStop Stop.
+ */
+ol.structs.IntegerSet.prototype.addRange = function(addStart, addStop) {
+  goog.asserts.assert(addStart <= addStop);
+  if (addStart == addStop) {
+    return;
+  }
+  var range = {start: addStart, stop: addStop};
+  goog.array.binaryInsert(this.ranges_, range, ol.structs.IntegerRange.compare);
+  this.compactRanges_();
+};
+
+
+/**
+ * FIXME empty description for jsdoc
+ */
+ol.structs.IntegerSet.prototype.assertValid = function() {
+  var arr = this.pack();
+  for (i = 1; i < arr.length; ++i) {
+    goog.asserts.assert(arr[i] > arr[i - 1]);
+  }
+};
+
+
+/**
+ * FIXME empty description for jsdoc
+ */
+ol.structs.IntegerSet.prototype.clear = function() {
+  this.ranges_.length = 0;
+};
+
+
+/**
+ * @private
+ */
+ol.structs.IntegerSet.prototype.compactRanges_ = function() {
+  var ranges = this.ranges_;
+  var n = ranges.length;
+  var rangeIndex = 0;
+  var lastRange = null;
+  var i;
+  for (i = 0; i < n; ++i) {
+    var range = ranges[i];
+    if (range.start == range.stop) {
+      // pass
+    } else if (!goog.isNull(lastRange) &&
+               lastRange.start <= range.start &&
+               range.start <= lastRange.stop) {
+      lastRange.stop = Math.max(lastRange.stop, range.stop);
+    } else {
+      lastRange = ranges[rangeIndex++] = range;
+    }
+  }
+  ranges.length = rangeIndex;
+};
+
+
+/**
+ * Finds the start of smallest range that is at least of length minSize, or -1
+ * if no such range exists.
+ * @param {number} minSize Minimum size.
+ * @return {number} Index.
+ */
+ol.structs.IntegerSet.prototype.findRange = function(minSize) {
+  goog.asserts.assert(minSize > 0);
+  var ranges = this.ranges_;
+  var n = ranges.length;
+  var bestRange = null;
+  var bestSize, i, size;
+  for (i = 0; i < n; ++i) {
+    range = ranges[i];
+    size = range.stop - range.start;
+    if (size == minSize) {
+      return range.start;
+    } else if (size > minSize && (goog.isNull(bestRange) || size < bestSize)) {
+      bestRange = range;
+      bestSize = size;
+    }
+  }
+  return goog.isNull(bestRange) ? -1 : bestRange.start;
+};
+
+
+/**
+ * Calls f with each integer range.
+ * @param {function(this: T, number, number)} f Callback.
+ * @param {T=} opt_obj The object to be used as the value of 'this' within f.
+ * @template T
+ */
+ol.structs.IntegerSet.prototype.forEachRange = function(f, opt_obj) {
+  var ranges = this.ranges_;
+  var n = ranges.length;
+  var i;
+  for (i = 0; i < n; ++i) {
+    f.call(opt_obj, ranges[i].start, ranges[i].stop);
+  }
+};
+
+
+/**
+ * Calls f with each integer range not in [start, stop) - 'this'.
+ * @param {number} start Start.
+ * @param {number} stop Stop.
+ * @param {function(this: T, number, number)} f Callback.
+ * @param {T=} opt_obj The object to be used as the value of 'this' within f.
+ * @template T
+ */
+ol.structs.IntegerSet.prototype.forEachRangeInverted =
+    function(start, stop, f, opt_obj) {
+  goog.asserts.assert(start < stop);
+  var ranges = this.ranges_;
+  var n = ranges.length;
+  if (n === 0) {
+    f.call(opt_obj, start, stop);
+  } else {
+    if (start < ranges[0].start) {
+      f.call(opt_obj, start, ranges[0].start);
+    }
+    var i;
+    for (i = 1; i < n; ++i) {
+      f.call(opt_obj, ranges[i - 1].stop, ranges[i].start);
+    }
+    if (ranges[n - 1].stop < stop) {
+      f.call(opt_obj, ranges[n - 1].stop, stop);
+    }
+  }
+};
+
+
+/**
+ * @return {Array.<number>} Array.
+ */
+ol.structs.IntegerSet.prototype.getArray = function() {
+  // FIXME this should return the underlying array when the representation is
+  // FIXME updated to use a packed array
+  return this.pack();
+};
+
+
+/**
+ * Returns the first element in the set, or -1 if the set is empty.
+ * @return {number} Start.
+ */
+ol.structs.IntegerSet.prototype.getFirst = function() {
+  return this.ranges_.length === 0 ? -1 : this.ranges_[0].start;
+};
+
+
+/**
+ * Returns the first integer after the last element in the set, or -1 if the
+ * set is empty.
+ * @return {number} Last.
+ */
+ol.structs.IntegerSet.prototype.getLast = function() {
+  var n = this.ranges_.length;
+  return n === 0 ? -1 : this.ranges_[n - 1].stop;
+};
+
+
+/**
+ * @return {Array.<ol.structs.IntegerRange>} Array.
+ */
+ol.structs.IntegerSet.prototype.getRanges = function() {
+  // FIXME this should be removed when the implementation is updated to use a
+  // FIXME packed array
+  return this.ranges_;
+};
+
+
+/**
+ * Returns the number of integers in the set.
+ * @return {number} Size.
+ */
+ol.structs.IntegerSet.prototype.getSize = function() {
+  var ranges = this.ranges_;
+  var n = ranges.length;
+  var size = 0;
+  for (i = 0; i < n; ++i) {
+    size += ranges[i].stop - ranges[i].start;
+  }
+  return size;
+};
+
+
+/**
+ * @return {boolean} Is empty.
+ */
+ol.structs.IntegerSet.prototype.isEmpty = function() {
+  return this.ranges_.length === 0;
+};
+
+
+/**
+ * @return {Array.<number>} Array.
+ */
+ol.structs.IntegerSet.prototype.pack = function() {
+  var ranges = this.ranges_;
+  var n = ranges.length;
+  var arr = new Array(2 * n);
+  var i;
+  for (i = 0; i < n; ++i) {
+    arr[2 * i] = ranges[i].start;
+    arr[2 * i + 1] = ranges[i].stop;
+  }
+  return arr;
+};
+
+
+/**
+ * @param {number} removeStart Start.
+ * @param {number} removeStop Stop.
+ */
+ol.structs.IntegerSet.prototype.removeRange =
+    function(removeStart, removeStop) {
+  // FIXME this could be more efficient
+  goog.asserts.assert(removeStart <= removeStop);
+  var ranges = this.ranges_;
+  var n = ranges.length;
+  for (i = 0; i < n; ++i) {
+    var range = ranges[i];
+    if (removeStop < range.start || range.stop < removeStart) {
+      continue;
+    } else if (range.start > removeStop) {
+      break;
+    }
+    if (removeStart < range.start) {
+      if (removeStop == range.start) {
+        break;
+      } else if (removeStop < range.stop) {
+        range.start = Math.max(range.start, removeStop);
+        break;
+      } else {
+        ranges.splice(i, 1);
+        --i;
+        --n;
+      }
+    } else if (removeStart == range.start) {
+      if (removeStop < range.stop) {
+        range.start = removeStop;
+        break;
+      } else if (removeStop == range.stop) {
+        ranges.splice(i, 1);
+        break;
+      } else {
+        ranges.splice(i, 1);
+        --i;
+        --n;
+      }
+    } else {
+      if (removeStop < range.stop) {
+        ranges.splice(i, 1, {start: range.start, stop: removeStart},
+            {start: removeStop, stop: range.stop});
+        break;
+      } else if (removeStop == range.stop) {
+        range.stop = removeStart;
+        break;
+      } else {
+        range.stop = removeStart;
+      }
+    }
+  }
+  this.compactRanges_();
+};
diff --git a/test/spec/ol/structs/integerset.test.js b/test/spec/ol/structs/integerset.test.js
new file mode 100644
index 0000000000..3513fde9e0
--- /dev/null
+++ b/test/spec/ol/structs/integerset.test.js
@@ -0,0 +1,552 @@
+goog.provide('ol.test.structs.IntegerSet');
+
+
+describe('ol.structs.IntegerSet', function() {
+
+  describe('constructor', function() {
+
+    describe('without an argument', function() {
+
+      it('constructs an empty instance', function() {
+        var is = new ol.structs.IntegerSet();
+        expect(is).to.be.an(ol.structs.IntegerSet);
+        expect(is.pack()).to.be.empty();
+      });
+
+    });
+
+  });
+
+  describe('unpack', function() {
+
+    it('constructs with a valid array', function() {
+      var is = ol.structs.IntegerSet.unpack([0, 2, 4, 6]);
+      expect(is).to.be.an(ol.structs.IntegerSet);
+      expect(is.pack()).to.equalArray([0, 2, 4, 6]);
+    });
+
+    it('throws an exception with an odd number of elements', function() {
+      expect(function() {
+        var is = ol.structs.IntegerSet.unpack([0, 2, 4]);
+      }).to.throwException();
+    });
+
+    it('throws an exception with out-of-order elements', function() {
+      expect(function() {
+        var is = ol.structs.IntegerSet.unpack([0, 2, 2, 4]);
+      }).to.throwException();
+    });
+
+  });
+
+  describe('with an empty instance', function() {
+
+    var is;
+    beforeEach(function() {
+      is = new ol.structs.IntegerSet();
+    });
+
+    describe('addRange', function() {
+
+      it('creates a new element', function() {
+        is.addRange(0, 2);
+        expect(is.pack()).to.equalArray([0, 2]);
+      });
+
+    });
+
+    describe('findRange', function() {
+
+      it('returns -1', function() {
+        expect(is.findRange(2)).to.be(-1);
+      });
+
+    });
+
+    describe('forEachRange', function() {
+
+      it('does not call the callback', function() {
+        var callback = sinon.spy();
+        is.forEachRange(callback);
+        expect(callback).to.not.be.called();
+      });
+
+    });
+
+    describe('forEachRangeInverted', function() {
+
+      it('does call the callback', function() {
+        var callback = sinon.spy();
+        is.forEachRangeInverted(0, 8, callback);
+        expect(callback.calledOnce).to.be(true);
+        expect(callback.args[0]).to.equalArray([0, 8]);
+      });
+
+    });
+
+    describe('getFirst', function() {
+
+      it('returns -1', function() {
+        expect(is.getFirst()).to.be(-1);
+      });
+
+    });
+
+    describe('getLast', function() {
+
+      it('returns -1', function() {
+        expect(is.getLast()).to.be(-1);
+      });
+
+    });
+
+    describe('getSize', function() {
+
+      it('returns 0', function() {
+        expect(is.getSize()).to.be(0);
+      });
+
+    });
+
+    describe('isEmpty', function() {
+
+      it('returns true', function() {
+        expect(is.isEmpty()).to.be(true);
+      });
+
+    });
+
+  });
+
+  describe('with a populated instance', function() {
+
+    var is;
+    beforeEach(function() {
+      is = ol.structs.IntegerSet.unpack([4, 6, 8, 10, 12, 14]);
+    });
+
+    describe('addRange', function() {
+
+      it('inserts before the first element', function() {
+        is.addRange(0, 2);
+        expect(is.pack()).to.equalArray([0, 2, 4, 6, 8, 10, 12, 14]);
+      });
+
+      it('extends the first element to the left', function() {
+        is.addRange(0, 4);
+        expect(is.pack()).to.equalArray([0, 6, 8, 10, 12, 14]);
+      });
+
+      it('extends the first element to the right', function() {
+        is.addRange(6, 7);
+        expect(is.pack()).to.equalArray([4, 7, 8, 10, 12, 14]);
+      });
+
+      it('merges the first two elements', function() {
+        is.addRange(6, 8);
+        expect(is.pack()).to.equalArray([4, 10, 12, 14]);
+      });
+
+      it('extends middle elements to the left', function() {
+        is.addRange(7, 8);
+        expect(is.pack()).to.equalArray([4, 6, 7, 10, 12, 14]);
+      });
+
+      it('extends middle elements to the right', function() {
+        is.addRange(10, 11);
+        expect(is.pack()).to.equalArray([4, 6, 8, 11, 12, 14]);
+      });
+
+      it('merges the last two elements', function() {
+        is.addRange(10, 12);
+        expect(is.pack()).to.equalArray([4, 6, 8, 14]);
+      });
+
+      it('extends the last element to the left', function() {
+        is.addRange(11, 12);
+        expect(is.pack()).to.equalArray([4, 6, 8, 10, 11, 14]);
+      });
+
+      it('extends the last element to the right', function() {
+        is.addRange(14, 15);
+        expect(is.pack()).to.equalArray([4, 6, 8, 10, 12, 15]);
+      });
+
+      it('inserts after the last element', function() {
+        is.addRange(16, 18);
+        expect(is.pack()).to.equalArray([4, 6, 8, 10, 12, 14, 16, 18]);
+      });
+
+    });
+
+    describe('clear', function() {
+
+      it('clears the instance', function() {
+        is.clear();
+        expect(is.pack()).to.be.empty();
+      });
+
+    });
+
+    describe('findRange', function() {
+
+      it('throws an exception when passed a negative size', function() {
+        expect(function() {
+          is.findRange(-1);
+        }).to.throwException();
+      });
+
+      it('throws an exception when passed a zero size', function() {
+        expect(function() {
+          is.findRange(0);
+        }).to.throwException();
+      });
+
+      it('finds the first range of size 1', function() {
+        expect(is.findRange(1)).to.be(4);
+      });
+
+      it('finds the first range of size 2', function() {
+        expect(is.findRange(2)).to.be(4);
+      });
+
+      it('returns -1 when no range can be found', function() {
+        expect(is.findRange(3)).to.be(-1);
+      });
+
+    });
+
+    describe('forEachRange', function() {
+
+      it('calls the callback', function() {
+        var callback = sinon.spy();
+        is.forEachRange(callback);
+        expect(callback).to.be.called();
+        expect(callback.calledThrice).to.be(true);
+        expect(callback.args[0]).to.equalArray([4, 6]);
+        expect(callback.args[1]).to.equalArray([8, 10]);
+        expect(callback.args[2]).to.equalArray([12, 14]);
+      });
+
+    });
+
+    describe('forEachRangeInverted', function() {
+
+      it('does call the callback', function() {
+        var callback = sinon.spy();
+        is.forEachRangeInverted(0, 16, callback);
+        expect(callback.callCount).to.be(4);
+        expect(callback.args[0]).to.equalArray([0, 4]);
+        expect(callback.args[1]).to.equalArray([6, 8]);
+        expect(callback.args[2]).to.equalArray([10, 12]);
+        expect(callback.args[3]).to.equalArray([14, 16]);
+      });
+
+    });
+
+
+    describe('getFirst', function() {
+
+      it('returns the expected value', function() {
+        expect(is.getFirst()).to.be(4);
+      });
+
+    });
+
+    describe('getLast', function() {
+
+      it('returns the expected value', function() {
+        expect(is.getLast()).to.be(14);
+      });
+
+    });
+
+    describe('getSize', function() {
+
+      it('returns the expected value', function() {
+        expect(is.getSize()).to.be(6);
+      });
+
+    });
+
+    describe('isEmpty', function() {
+
+      it('returns false', function() {
+        expect(is.isEmpty()).to.be(false);
+      });
+
+    });
+
+    describe('removeRange', function() {
+
+      it('removes the first part of the first element', function() {
+        is.removeRange(4, 5);
+        expect(is.pack()).to.equalArray([5, 6, 8, 10, 12, 14]);
+      });
+
+      it('removes the last part of the first element', function() {
+        is.removeRange(5, 6);
+        expect(is.pack()).to.equalArray([4, 5, 8, 10, 12, 14]);
+      });
+
+      it('removes the first element', function() {
+        is.removeRange(4, 6);
+        expect(is.pack()).to.equalArray([8, 10, 12, 14]);
+      });
+
+      it('removes the first part of a middle element', function() {
+        is.removeRange(8, 9);
+        expect(is.pack()).to.equalArray([4, 6, 9, 10, 12, 14]);
+      });
+
+      it('removes the last part of a middle element', function() {
+        is.removeRange(9, 10);
+        expect(is.pack()).to.equalArray([4, 6, 8, 9, 12, 14]);
+      });
+
+      it('removes a middle element', function() {
+        is.removeRange(8, 10);
+        expect(is.pack()).to.equalArray([4, 6, 12, 14]);
+      });
+
+      it('removes the first part of the last element', function() {
+        is.removeRange(12, 13);
+        expect(is.pack()).to.equalArray([4, 6, 8, 10, 13, 14]);
+      });
+
+      it('removes the last part of the last element', function() {
+        is.removeRange(13, 14);
+        expect(is.pack()).to.equalArray([4, 6, 8, 10, 12, 13]);
+      });
+
+      it('removes the last element', function() {
+        is.removeRange(12, 14);
+        expect(is.pack()).to.equalArray([4, 6, 8, 10]);
+      });
+
+      it('can remove multiple ranges near the start', function() {
+        is.removeRange(3, 11);
+        expect(is.pack()).to.equalArray([12, 14]);
+      });
+
+      it('can remove multiple ranges near the start', function() {
+        is.removeRange(7, 15);
+        expect(is.pack()).to.equalArray([4, 6]);
+      });
+
+      it('throws an exception when passed an invalid range', function() {
+        expect(function() {
+          is.removeRange(2, 0);
+        }).to.throwException();
+      });
+
+    });
+
+  });
+
+  describe('with fragmentation', function() {
+
+    var is;
+    beforeEach(function() {
+      is = ol.structs.IntegerSet.unpack(
+          [0, 1, 2, 4, 5, 8, 9, 12, 13, 15, 16, 17]);
+    });
+
+    describe('findRange', function() {
+
+      it('finds the first range of size 1', function() {
+        expect(is.findRange(1)).to.be(0);
+      });
+
+      it('finds the first range of size 2', function() {
+        expect(is.findRange(2)).to.be(2);
+      });
+
+      it('finds the first range of size 3', function() {
+        expect(is.findRange(3)).to.be(5);
+      });
+
+      it('returns -1 when no range can be found', function() {
+        expect(is.findRange(4)).to.be(-1);
+      });
+
+    });
+
+    describe('getFirst', function() {
+
+      it('returns the expected value', function() {
+        expect(is.getFirst()).to.be(0);
+      });
+
+    });
+
+    describe('getLast', function() {
+
+      it('returns the expected value', function() {
+        expect(is.getLast()).to.be(17);
+      });
+
+    });
+
+    describe('getSize', function() {
+
+      it('returns the expected value', function() {
+        expect(is.getSize()).to.be(12);
+      });
+
+    });
+
+    describe('removeRange', function() {
+
+      it('removing an empty range has no effect', function() {
+        is.removeRange(0, 0);
+        expect(is.pack()).to.equalArray(
+            [0, 1, 2, 4, 5, 8, 9, 12, 13, 15, 16, 17]);
+      });
+
+      it('can remove elements from the middle of range', function() {
+        is.removeRange(6, 7);
+        expect(is.pack()).to.equalArray(
+            [0, 1, 2, 4, 5, 6, 7, 8, 9, 12, 13, 15, 16, 17]);
+      });
+
+      it('can remove multiple ranges', function() {
+        is.removeRange(2, 12);
+        expect(is.pack()).to.equalArray([0, 1, 13, 15, 16, 17]);
+      });
+
+      it('can remove multiple ranges and reduce others', function() {
+        is.removeRange(0, 10);
+        expect(is.pack()).to.equalArray([10, 12, 13, 15, 16, 17]);
+      });
+
+      it('can remove all ranges', function() {
+        is.removeRange(0, 18);
+        expect(is.pack()).to.equalArray([]);
+      });
+
+    });
+
+  });
+
+  describe('compared to a slow reference implementation', function() {
+
+    var SimpleIntegerSet = function() {
+      this.integers_ = {};
+    };
+
+    SimpleIntegerSet.prototype.addRange = function(addStart, addStop) {
+      var i;
+      for (i = addStart; i < addStop; ++i) {
+        this.integers_[i.toString()] = true;
+      }
+    };
+
+    SimpleIntegerSet.prototype.clear = function() {
+      this.integers_ = {};
+    };
+
+    SimpleIntegerSet.prototype.pack = function() {
+      var integers = goog.array.map(
+          goog.object.getKeys(this.integers_), Number);
+      goog.array.sort(integers);
+      var arr = [];
+      var start = -1, stop;
+      var i;
+      for (i = 0; i < integers.length; ++i) {
+        if (start == -1) {
+          start = stop = integers[i];
+        } else if (integers[i] == stop + 1) {
+          ++stop;
+        } else {
+          arr.push(start, stop + 1);
+          start = stop = integers[i];
+        }
+      }
+      if (start != -1) {
+        arr.push(start, stop + 1);
+      }
+      return arr;
+    };
+
+    SimpleIntegerSet.prototype.removeRange = function(removeStart, removeStop) {
+      var i;
+      for (i = removeStart; i < removeStop; ++i) {
+        delete this.integers_[i.toString()];
+      }
+    };
+
+    var is, sis;
+    beforeEach(function() {
+      is = new ol.structs.IntegerSet();
+      sis = new SimpleIntegerSet();
+    });
+
+    it('behaves identically with random adds', function() {
+      var addStart, addStop, i;
+      for (i = 0; i < 64; ++i) {
+        addStart = goog.math.randomInt(128);
+        addStop = addStart + goog.math.randomInt(16);
+        is.addRange(addStart, addStop);
+        sis.addRange(addStart, addStop);
+        expect(is.pack()).to.equalArray(sis.pack());
+      }
+    });
+
+    it('behaves identically with random removes', function() {
+      is.addRange(0, 128);
+      sis.addRange(0, 128);
+      var i, removeStart, removeStop;
+      for (i = 0; i < 64; ++i) {
+        removeStart = goog.math.randomInt(128);
+        removeStop = removeStart + goog.math.randomInt(16);
+        is.removeRange(removeStart, removeStop);
+        sis.removeRange(removeStart, removeStop);
+        expect(is.pack()).to.equalArray(sis.pack());
+      }
+    });
+
+    it('behaves identically with random adds and removes', function() {
+      var i, start, stop;
+      for (i = 0; i < 64; ++i) {
+        start = goog.math.randomInt(128);
+        stop = start + goog.math.randomInt(16);
+        if (Math.random() < 0.5) {
+          is.addRange(start, stop);
+          sis.addRange(start, stop);
+        } else {
+          is.removeRange(start, stop);
+          sis.removeRange(start, stop);
+        }
+        expect(is.pack()).to.equalArray(sis.pack());
+      }
+    });
+
+    it('behaves identically with random adds, removes, and clears', function() {
+      var i, p, start, stop;
+      for (i = 0; i < 64; ++i) {
+        start = goog.math.randomInt(128);
+        stop = start + goog.math.randomInt(16);
+        p = Math.random();
+        if (p < 0.45) {
+          is.addRange(start, stop);
+          sis.addRange(start, stop);
+        } else if (p < 0.9) {
+          is.removeRange(start, stop);
+          sis.removeRange(start, stop);
+        } else {
+          is.clear();
+          sis.clear();
+        }
+        expect(is.pack()).to.equalArray(sis.pack());
+      }
+    });
+
+  });
+
+});
+
+
+goog.require('goog.array');
+goog.require('goog.object');
+goog.require('ol.structs.IntegerSet');