text: import Collection from '../../../../src/ol/Collection.js';
  import CollectionEventType from '../../../../src/ol/CollectionEventType.js';
  import {listen} from '../../../../src/ol/events.js';
  
  describe('ol.collection', function () {
    let collection;
  
    beforeEach(function () {
      collection = new Collection();
    });
  
    describe('create an empty collection', function () {
      it('creates an empty collection', function () {
        expect(collection.getLength()).to.eql(0);
        expect(collection.getArray()).to.be.empty();
        expect(collection.item(0)).to.be(undefined);
      });
    });
  
    describe('create a collection from an array', function () {
      it('creates the expected collection', function () {
        const array = [0, 1, 2];
        const collection = new Collection(array);
        expect(collection.item(0)).to.eql(0);
        expect(collection.item(1)).to.eql(1);
        expect(collection.item(2)).to.eql(2);
      });
    });
  
    describe('push to a collection', function () {
      it('adds elements to the collection', function () {
        const length = collection.push(1);
        expect(collection.getLength()).to.eql(length);
        expect(collection.getArray()).to.eql([1]);
        expect(collection.item(0)).to.eql(1);
      });
      it('returns the correct new length of the collection', function () {
        let length;
        listen(collection, 'add', function (event) {
          if (event.element === 'remove_me') {
            collection.remove(event.element);
          }
        });
        length = collection.push('keep_me');
        expect(collection.getLength()).to.eql(length);
        length = collection.push('remove_me');
        expect(collection.getLength()).to.eql(length);
      });
    });
  
    describe('pop from a collection', function () {
      it('removes elements from the collection', function () {
        collection.push(1);
        collection.pop();
        expect(collection.getLength()).to.eql(0);
        expect(collection.getArray()).to.be.empty();
        expect(collection.item(0)).to.be(undefined);
      });
    });
  
    describe('insertAt', function () {
      it('inserts elements at the correct location', function () {
        collection = new Collection([0, 2]);
        collection.insertAt(1, 1);
        expect(collection.item(0)).to.eql(0);
        expect(collection.item(1)).to.eql(1);
        expect(collection.item(2)).to.eql(2);
      });
    });
  
    describe('setAt', function () {
      it('sets at the correct location', function () {
        collection.setAt(1, 1);
        expect(collection.getLength()).to.eql(2);
        expect(collection.item(0)).to.be(undefined);
        expect(collection.item(1)).to.eql(1);
      });
    });
  
    describe('removeAt', function () {
      it('removes elements at the correction', function () {
        const collection = new Collection([0, 1, 2]);
        collection.removeAt(1);
        expect(collection.item(0)).to.eql(0);
        expect(collection.item(1)).to.eql(2);
      });
    });
  
    describe('forEach', function () {
      let cb;
      beforeEach(function () {
        cb = sinon.spy();
      });
      describe('on an empty collection', function () {
        it('does not call the callback', function () {
          collection.forEach(cb);
          expect(cb.called).to.be(false);
        });
      });
      describe('on a non-empty collection', function () {
        it('does call the callback', function () {
          collection.push(1);
          collection.push(2);
          collection.forEach(cb);
          expect(cb.callCount).to.eql(2);
        });
      });
    });
  
    describe('remove', function () {
      it('removes the first matching element', function () {
        const collection = new Collection([0, 1, 2]);
        expect(collection.remove(1)).to.eql(1);
        expect(collection.getArray()).to.eql([0, 2]);
        expect(collection.getLength()).to.eql(2);
      });
      it('fires a remove event', function () {
        const collection = new Collection([0, 1, 2]);
        const cb = sinon.spy();
        listen(collection, CollectionEventType.REMOVE, cb);
        expect(collection.remove(1)).to.eql(1);
        expect(cb.called).to.be(true);
        expect(cb.lastCall.args[0].element).to.eql(1);
      });
      it('does not remove more than one matching element', function () {
        const collection = new Collection([0, 1, 1, 2]);
        expect(collection.remove(1)).to.eql(1);
        expect(collection.getArray()).to.eql([0, 1, 2]);
        expect(collection.getLength()).to.eql(3);
      });
      it('returns undefined if the element is not found', function () {
        const collection = new Collection([0, 1, 2]);
        expect(collection.remove(3)).to.be(undefined);
        expect(collection.getArray()).to.eql([0, 1, 2]);
        expect(collection.getLength()).to.eql(3);
      });
    });
  
    describe('setAt and event', function () {
      it('does dispatch events', function () {
        const collection = new Collection(['a', 'b']);
        let added, removed, addedIndex, removedIndex;
        listen(collection, CollectionEventType.ADD, function (e) {
          added = e.element;
          addedIndex = e.index;
        });
        listen(collection, CollectionEventType.REMOVE, function (e) {
          removed = e.element;
          removedIndex = e.index;
        });
        collection.setAt(1, 1);
        expect(added).to.eql(1);
        expect(addedIndex).to.eql(1);
        expect(removed).to.eql('b');
        expect(removedIndex).to.eql(1);
      });
    });
  
    describe('removeAt and event', function () {
      it('does dispatch events', function () {
        const collection = new Collection(['a']);
        let removed, removedIndex;
        listen(collection, CollectionEventType.REMOVE, function (e) {
          removed = e.element;
          removedIndex = e.index;
        });
        collection.pop();
        expect(removed).to.eql('a');
        expect(removedIndex).to.eql(0);
      });
    });
  
    describe('insertAt and event', function () {
      it('does dispatch events', function () {
        const collection = new Collection([0, 2]);
        let added, addedIndex;
        listen(collection, CollectionEventType.ADD, function (e) {
          added = e.element;
          addedIndex = e.index;
        });
        collection.insertAt(1, 1);
        expect(added).to.eql(1);
        expect(addedIndex).to.eql(1);
      });
    });
  
    describe('setAt beyond end', function () {
      it('triggers events properly', function () {
        const added = [],
          addedIndexes = [];
        listen(collection, CollectionEventType.ADD, function (e) {
          added.push(e.element);
          addedIndexes.push(e.index);
        });
        collection.setAt(2, 0);
        expect(collection.getLength()).to.eql(3);
        expect(collection.item(0)).to.be(undefined);
        expect(collection.item(1)).to.be(undefined);
        expect(collection.item(2)).to.eql(0);
        expect(added.length).to.eql(3);
        expect(added[0]).to.eql(undefined);
        expect(added[1]).to.eql(undefined);
        expect(added[2]).to.eql(0);
        expect(addedIndexes).to.eql([0, 1, 2]);
      });
    });
  
    describe('change:length event', function () {
      let collection, cb;
      beforeEach(function () {
        collection = new Collection([0, 1, 2]);
        cb = sinon.spy();
        listen(collection, 'change:length', cb);
      });
  
      describe('insertAt', function () {
        it('triggers change:length event', function () {
          collection.insertAt(2, 3);
          expect(cb.called).to.be(true);
        });
      });
  
      describe('removeAt', function () {
        it('triggers change:length event', function () {
          collection.removeAt(0);
          expect(cb.called).to.be(true);
        });
      });
  
      describe('setAt', function () {
        it('does not trigger change:length event', function () {
          collection.setAt(1, 1);
          expect(cb.called).to.be(false);
        });
      });
    });
  
    describe('add event', function () {
      it('triggers add when pushing', function () {
        const collection = new Collection();
        let elem, addedIndex;
        listen(collection, CollectionEventType.ADD, function (e) {
          elem = e.element;
          addedIndex = e.index;
        });
        const length = collection.push(1);
        expect(elem).to.eql(length);
        expect(addedIndex).to.eql(0);
      });
    });
  
    describe('remove event', function () {
      let collection, cb1, cb2;
      beforeEach(function () {
        collection = new Collection([1]);
        cb1 = sinon.spy();
        cb2 = sinon.spy();
      });
      describe('setAt', function () {
        it('triggers remove', function () {
          listen(collection, CollectionEventType.ADD, cb1);
          listen(collection, CollectionEventType.REMOVE, cb2);
          collection.setAt(0, 2);
          expect(cb2.lastCall.args[0].element).to.eql(1);
          expect(cb1.lastCall.args[0].element).to.eql(2);
        });
      });
      describe('pop', function () {
        it('triggers remove', function () {
          listen(collection, CollectionEventType.REMOVE, cb1);
          collection.pop();
          expect(cb1.lastCall.args[0].element).to.eql(1);
        });
      });
    });
  
    describe('extending a collection', function () {
      it('adds elements to end of the collection', function () {
        collection.extend([1, 2]);
        expect(collection.getLength()).to.eql(2);
        expect(collection.getArray()).to.eql([1, 2]);
        expect(collection.item(0)).to.eql(1);
        expect(collection.item(1)).to.eql(2);
      });
      it('fires events', function () {
        const collection = new Collection();
        const elems = [],
          addedIndexes = [];
        listen(collection, CollectionEventType.ADD, function (e) {
          elems.push(e.element);
          addedIndexes.push(e.index);
        });
        collection.extend([1, 2]);
        expect(elems).to.eql([1, 2]);
        expect(addedIndexes).to.eql([0, 1]);
      });
    });
  
    describe('unique collection', function () {
      it('allows unique items in the constructor', function () {
        new Collection([{}, {}, {}], {unique: true});
      });
  
      it('throws if duplicate items are passed to the constructor', function () {
        const item = {};
        const call = function () {
          new Collection([item, item], {unique: true});
        };
        expect(call).to.throwException();
      });
  
      it('allows unique items to be added via push', function () {
        const unique = new Collection(undefined, {unique: true});
        unique.push({});
        unique.push({});
      });
  
      it('throws if duplicate items are added via push', function () {
        const unique = new Collection(undefined, {unique: true});
        const item = {};
        unique.push(item);
        const call = function () {
          unique.push(item);
        };
        expect(call).to.throwException();
      });
  
      it('allows unique items to be added via insertAt', function () {
        const unique = new Collection(undefined, {unique: true});
        unique.insertAt(0, {});
        unique.insertAt(0, {});
      });
  
      it('throws if duplicate items are added via insertAt', function () {
        const unique = new Collection(undefined, {unique: true});
        const item = {};
        unique.insertAt(0, item);
        const call = function () {
          unique.insertAt(0, item);
        };
        expect(call).to.throwException();
      });
  
      it('allows unique items to be added via setAt', function () {
        const unique = new Collection(undefined, {unique: true});
        unique.setAt(0, {});
        unique.setAt(1, {});
      });
  
      it('allows items to be reset via setAt', function () {
        const unique = new Collection(undefined, {unique: true});
        const item = {};
        unique.setAt(0, item);
        unique.setAt(0, item);
      });
  
      it('throws if duplicate items are added via setAt', function () {
        const unique = new Collection(undefined, {unique: true});
        const item = {};
        unique.setAt(0, item);
        const call = function () {
          unique.setAt(1, item);
        };
        expect(call).to.throwException();
      });
    });
  });
  