text: import * as _ol_extent_ from '../../../../src/ol/extent.js';
  import {get, getTransform} from '../../../../src/ol/proj.js';
  import {register} from '../../../../src/ol/proj/proj4.js';
  
  describe('ol.extent', function () {
    describe('buffer', function () {
      it('buffers an extent by some value', function () {
        const extent = [-10, -20, 10, 20];
        expect(_ol_extent_.buffer(extent, 15)).to.eql([-25, -35, 25, 35]);
      });
    });
  
    describe('clone', function () {
      it('creates a copy of an extent', function () {
        const extent = _ol_extent_.createOrUpdate(1, 2, 3, 4);
        const clone = _ol_extent_.clone(extent);
        expect(_ol_extent_.equals(extent, clone)).to.be(true);
  
        _ol_extent_.extendCoordinate(extent, [10, 20]);
        expect(_ol_extent_.equals(extent, clone)).to.be(false);
      });
    });
  
    describe('closestSquaredDistanceXY', function () {
      it('returns correct result when x left of extent', function () {
        const extent = _ol_extent_.createOrUpdate(0, 0, 1, 1);
        const x = -2;
        const y = 0;
        expect(_ol_extent_.closestSquaredDistanceXY(extent, x, y)).to.be(4);
      });
  
      it('returns correct result when x right of extent', function () {
        const extent = _ol_extent_.createOrUpdate(0, 0, 1, 1);
        const x = 3;
        const y = 0;
        expect(_ol_extent_.closestSquaredDistanceXY(extent, x, y)).to.be(4);
      });
  
      it('returns correct result for other x values', function () {
        const extent = _ol_extent_.createOrUpdate(0, 0, 1, 1);
        const x = 0.5;
        const y = 3;
        expect(_ol_extent_.closestSquaredDistanceXY(extent, x, y)).to.be(4);
      });
  
      it('returns correct result when y below extent', function () {
        const extent = _ol_extent_.createOrUpdate(0, 0, 1, 1);
        const x = 0;
        const y = -2;
        expect(_ol_extent_.closestSquaredDistanceXY(extent, x, y)).to.be(4);
      });
  
      it('returns correct result when y above extent', function () {
        const extent = _ol_extent_.createOrUpdate(0, 0, 1, 1);
        const x = 0;
        const y = 3;
        expect(_ol_extent_.closestSquaredDistanceXY(extent, x, y)).to.be(4);
      });
  
      it('returns correct result for other y values', function () {
        const extent = _ol_extent_.createOrUpdate(0, 0, 1, 1);
        const x = 3;
        const y = 0.5;
        expect(_ol_extent_.closestSquaredDistanceXY(extent, x, y)).to.be(4);
      });
    });
  
    describe('createOrUpdateFromCoordinate', function () {
      it('works when no extent passed', function () {
        const coords = [0, 1];
        const expected = [0, 1, 0, 1];
        const got = _ol_extent_.createOrUpdateFromCoordinate(coords);
        expect(got).to.eql(expected);
      });
  
      it('updates a passed extent', function () {
        const extent = _ol_extent_.createOrUpdate(-4, -7, -3, -6);
        const coords = [0, 1];
        const expected = [0, 1, 0, 1];
        _ol_extent_.createOrUpdateFromCoordinate(coords, extent);
        expect(extent).to.eql(expected);
      });
    });
  
    describe('createOrUpdateFromCoordinates', function () {
      it('works when single coordinate and no extent passed', function () {
        const coords = [[0, 1]];
        const expected = [0, 1, 0, 1];
        const got = _ol_extent_.createOrUpdateFromCoordinates(coords);
        expect(got).to.eql(expected);
      });
  
      it('changes the passed extent when single coordinate', function () {
        const extent = _ol_extent_.createOrUpdate(-4, -7, -3, -6);
        const coords = [[0, 1]];
        const expected = [0, 1, 0, 1];
        _ol_extent_.createOrUpdateFromCoordinates(coords, extent);
        expect(extent).to.eql(expected);
      });
  
      it('works when multiple coordinates and no extent passed', function () {
        const coords = [
          [0, 1],
          [2, 3],
        ];
        const expected = [0, 1, 2, 3];
        const got = _ol_extent_.createOrUpdateFromCoordinates(coords);
        expect(got).to.eql(expected);
      });
  
      it('changes the passed extent when multiple coordinates given', function () {
        const extent = _ol_extent_.createOrUpdate(-4, -7, -3, -6);
        const coords = [
          [0, 1],
          [-2, -1],
        ];
        const expected = [-2, -1, 0, 1];
        _ol_extent_.createOrUpdateFromCoordinates(coords, extent);
        expect(extent).to.eql(expected);
      });
    });
  
    describe('createOrUpdateFromRings', function () {
      it('works when single ring and no extent passed', function () {
        const ring = [
          [0, 0],
          [0, 2],
          [2, 2],
          [2, 0],
          [0, 0],
        ];
        const rings = [ring];
        const expected = [0, 0, 2, 2];
        const got = _ol_extent_.createOrUpdateFromRings(rings);
        expect(got).to.eql(expected);
      });
  
      it('changes the passed extent when single ring given', function () {
        const ring = [
          [0, 0],
          [0, 2],
          [2, 2],
          [2, 0],
          [0, 0],
        ];
        const rings = [ring];
        const extent = [1, 1, 4, 7];
        const expected = [0, 0, 2, 2];
        _ol_extent_.createOrUpdateFromRings(rings, extent);
        expect(extent).to.eql(expected);
      });
  
      it('works when multiple rings and no extent passed', function () {
        const ring1 = [
          [0, 0],
          [0, 2],
          [2, 2],
          [2, 0],
          [0, 0],
        ];
        const ring2 = [
          [1, 1],
          [1, 3],
          [3, 3],
          [3, 1],
          [1, 1],
        ];
        const rings = [ring1, ring2];
        const expected = [0, 0, 3, 3];
        const got = _ol_extent_.createOrUpdateFromRings(rings);
        expect(got).to.eql(expected);
      });
  
      it('changes the passed extent when multiple rings given', function () {
        const ring1 = [
          [0, 0],
          [0, 2],
          [2, 2],
          [2, 0],
          [0, 0],
        ];
        const ring2 = [
          [1, 1],
          [1, 3],
          [3, 3],
          [3, 1],
          [1, 1],
        ];
        const rings = [ring1, ring2];
        const extent = [1, 1, 4, 7];
        const expected = [0, 0, 3, 3];
        _ol_extent_.createOrUpdateFromRings(rings, extent);
        expect(extent).to.eql(expected);
      });
    });
  
    describe('forEachCorner', function () {
      let callbackFalse;
      let callbackTrue;
      beforeEach(function () {
        callbackFalse = sinon.spy(function () {
          return false;
        });
        callbackTrue = sinon.spy(function () {
          return true;
        });
      });
  
      it('calls the passed callback for each corner', function () {
        const extent = [1, 2, 3, 4];
        _ol_extent_.forEachCorner(extent, callbackFalse);
        expect(callbackFalse.callCount).to.be(4);
      });
  
      it('calls the passed callback with each corner', function () {
        const extent = [1, 2, 3, 4];
        _ol_extent_.forEachCorner(extent, callbackFalse);
        const firstCallFirstArg = callbackFalse.args[0][0];
        const secondCallFirstArg = callbackFalse.args[1][0];
        const thirdCallFirstArg = callbackFalse.args[2][0];
        const fourthCallFirstArg = callbackFalse.args[3][0];
        expect(firstCallFirstArg).to.eql([1, 2]); // bl
        expect(secondCallFirstArg).to.eql([3, 2]); // br
        expect(thirdCallFirstArg).to.eql([3, 4]); // tr
        expect(fourthCallFirstArg).to.eql([1, 4]); // tl
      });
  
      it('calls a truthy callback only once', function () {
        const extent = [1, 2, 3, 4];
        _ol_extent_.forEachCorner(extent, callbackTrue);
        expect(callbackTrue.callCount).to.be(1);
      });
  
      it('ensures that any corner can cancel the callback execution', function () {
        const extent = [1, 2, 3, 4];
        const bottomLeftSpy = sinon.spy(function (corner) {
          return corner[0] === 1 && corner[1] === 2 ? true : false;
        });
        const bottomRightSpy = sinon.spy(function (corner) {
          return corner[0] === 3 && corner[1] === 2 ? true : false;
        });
        const topRightSpy = sinon.spy(function (corner) {
          return corner[0] === 3 && corner[1] === 4 ? true : false;
        });
        const topLeftSpy = sinon.spy(function (corner) {
          return corner[0] === 1 && corner[1] === 4 ? true : false;
        });
  
        _ol_extent_.forEachCorner(extent, bottomLeftSpy);
        _ol_extent_.forEachCorner(extent, bottomRightSpy);
        _ol_extent_.forEachCorner(extent, topRightSpy);
        _ol_extent_.forEachCorner(extent, topLeftSpy);
  
        expect(bottomLeftSpy.callCount).to.be(1);
        expect(bottomRightSpy.callCount).to.be(2);
        expect(topRightSpy.callCount).to.be(3);
        expect(topLeftSpy.callCount).to.be(4);
      });
  
      it('returns false eventually, if no invocation returned a truthy value', function () {
        const extent = [1, 2, 3, 4];
        const spy = sinon.spy(); // will return undefined for each corner
        const got = _ol_extent_.forEachCorner(extent, spy);
        expect(spy.callCount).to.be(4);
        expect(got).to.be(false);
      });
    });
  
    describe('getArea', function () {
      it('returns zero for empty extents', function () {
        const emptyExtent = _ol_extent_.createEmpty();
        const areaEmpty = _ol_extent_.getArea(emptyExtent);
        expect(areaEmpty).to.be(0);
  
        const extentDeltaXZero = [45, 67, 45, 78];
        const areaDeltaXZero = _ol_extent_.getArea(extentDeltaXZero);
        expect(areaDeltaXZero).to.be(0);
  
        const extentDeltaYZero = [11, 67, 45, 67];
        const areaDeltaYZero = _ol_extent_.getArea(extentDeltaYZero);
        expect(areaDeltaYZero).to.be(0);
      });
      it('calculates correct area for other extents', function () {
        const extent = [0, 0, 10, 10];
        const area = _ol_extent_.getArea(extent);
        expect(area).to.be(100);
      });
    });
  
    describe('getIntersection()', function () {
      it('returns the intersection of two extents', function () {
        const world = [-180, -90, 180, 90];
        const north = [-180, 0, 180, 90];
        const farNorth = [-180, 45, 180, 90];
        const east = [0, -90, 180, 90];
        const farEast = [90, -90, 180, 90];
        const south = [-180, -90, 180, 0];
        const farSouth = [-180, -90, 180, -45];
        const west = [-180, -90, 0, 90];
        const farWest = [-180, -90, -90, 90];
        const none = _ol_extent_.createEmpty();
        expect(_ol_extent_.getIntersection(world, none)).to.eql(none);
        expect(_ol_extent_.getIntersection(world, north)).to.eql(north);
        expect(_ol_extent_.getIntersection(world, east)).to.eql(east);
        expect(_ol_extent_.getIntersection(world, south)).to.eql(south);
        expect(_ol_extent_.getIntersection(world, west)).to.eql(west);
        expect(_ol_extent_.getIntersection(farEast, farWest)).to.eql(none);
        expect(_ol_extent_.getIntersection(farNorth, farSouth)).to.eql(none);
        expect(_ol_extent_.getIntersection(north, west)).to.eql([-180, 0, 0, 90]);
        expect(_ol_extent_.getIntersection(east, south)).to.eql([0, -90, 180, 0]);
      });
  
      it('can take an destination extent', function () {
        const world = [-180, -90, 180, 90];
        const north = [-180, 0, 180, 90];
        const none = _ol_extent_.createEmpty();
        let tmpExtent = [-180, 45, 180, 90];
        expect(_ol_extent_.getIntersection(world, north, tmpExtent)).to.eql(
          north
        );
        expect(_ol_extent_.getIntersection(world, none, tmpExtent)).to.eql(none);
  
        tmpExtent = [-180, -90, 180, 90];
        expect(_ol_extent_.getIntersection(tmpExtent, north, tmpExtent)).to.eql(
          north
        );
      });
    });
  
    describe('containsCoordinate', function () {
      describe('positive', function () {
        it('returns true', function () {
          const extent = [1, 2, 3, 4];
          expect(_ol_extent_.containsCoordinate(extent, [1, 2])).to.be.ok();
          expect(_ol_extent_.containsCoordinate(extent, [1, 3])).to.be.ok();
          expect(_ol_extent_.containsCoordinate(extent, [1, 4])).to.be.ok();
          expect(_ol_extent_.containsCoordinate(extent, [2, 2])).to.be.ok();
          expect(_ol_extent_.containsCoordinate(extent, [2, 3])).to.be.ok();
          expect(_ol_extent_.containsCoordinate(extent, [2, 4])).to.be.ok();
          expect(_ol_extent_.containsCoordinate(extent, [3, 2])).to.be.ok();
          expect(_ol_extent_.containsCoordinate(extent, [3, 3])).to.be.ok();
          expect(_ol_extent_.containsCoordinate(extent, [3, 4])).to.be.ok();
        });
      });
  
      describe('negative', function () {
        it('returns false', function () {
          const extent = [1, 2, 3, 4];
          expect(_ol_extent_.containsCoordinate(extent, [0, 1])).to.not.be();
          expect(_ol_extent_.containsCoordinate(extent, [0, 2])).to.not.be();
          expect(_ol_extent_.containsCoordinate(extent, [0, 3])).to.not.be();
          expect(_ol_extent_.containsCoordinate(extent, [0, 4])).to.not.be();
          expect(_ol_extent_.containsCoordinate(extent, [0, 5])).to.not.be();
          expect(_ol_extent_.containsCoordinate(extent, [1, 1])).to.not.be();
          expect(_ol_extent_.containsCoordinate(extent, [1, 5])).to.not.be();
          expect(_ol_extent_.containsCoordinate(extent, [2, 1])).to.not.be();
          expect(_ol_extent_.containsCoordinate(extent, [2, 5])).to.not.be();
          expect(_ol_extent_.containsCoordinate(extent, [3, 1])).to.not.be();
          expect(_ol_extent_.containsCoordinate(extent, [3, 5])).to.not.be();
          expect(_ol_extent_.containsCoordinate(extent, [4, 1])).to.not.be();
          expect(_ol_extent_.containsCoordinate(extent, [4, 2])).to.not.be();
          expect(_ol_extent_.containsCoordinate(extent, [4, 3])).to.not.be();
          expect(_ol_extent_.containsCoordinate(extent, [4, 4])).to.not.be();
          expect(_ol_extent_.containsCoordinate(extent, [4, 5])).to.not.be();
        });
      });
    });
  
    describe('coordinateRelationship()', function () {
      const extent = [-180, -90, 180, 90];
      const INTERSECTING = 1;
      const ABOVE = 2;
      const RIGHT = 4;
      const BELOW = 8;
      const LEFT = 16;
  
      it('returns intersecting for within', function () {
        const rel = _ol_extent_.coordinateRelationship(extent, [0, 0]);
        expect(rel).to.be(INTERSECTING);
      });
  
      it('returns intersecting for touching top', function () {
        const rel = _ol_extent_.coordinateRelationship(extent, [0, 90]);
        expect(rel).to.be(INTERSECTING);
      });
  
      it('returns intersecting for touching right', function () {
        const rel = _ol_extent_.coordinateRelationship(extent, [180, 0]);
        expect(rel).to.be(INTERSECTING);
      });
  
      it('returns intersecting for touching bottom', function () {
        const rel = _ol_extent_.coordinateRelationship(extent, [0, -90]);
        expect(rel).to.be(INTERSECTING);
      });
  
      it('returns intersecting for touching left', function () {
        const rel = _ol_extent_.coordinateRelationship(extent, [-180, 0]);
        expect(rel).to.be(INTERSECTING);
      });
  
      it('above for north', function () {
        const rel = _ol_extent_.coordinateRelationship(extent, [0, 100]);
        expect(rel).to.be(ABOVE);
      });
  
      it('above and right for northeast', function () {
        const rel = _ol_extent_.coordinateRelationship(extent, [190, 100]);
        expect(rel & ABOVE).to.be(ABOVE);
        expect(rel & RIGHT).to.be(RIGHT);
      });
  
      it('right for east', function () {
        const rel = _ol_extent_.coordinateRelationship(extent, [190, 0]);
        expect(rel).to.be(RIGHT);
      });
  
      it('below and right for southeast', function () {
        const rel = _ol_extent_.coordinateRelationship(extent, [190, -100]);
        expect(rel & BELOW).to.be(BELOW);
        expect(rel & RIGHT).to.be(RIGHT);
      });
  
      it('below for south', function () {
        const rel = _ol_extent_.coordinateRelationship(extent, [0, -100]);
        expect(rel).to.be(BELOW);
      });
  
      it('below and left for southwest', function () {
        const rel = _ol_extent_.coordinateRelationship(extent, [-190, -100]);
        expect(rel & BELOW).to.be(BELOW);
        expect(rel & LEFT).to.be(LEFT);
      });
  
      it('left for west', function () {
        const rel = _ol_extent_.coordinateRelationship(extent, [-190, 0]);
        expect(rel).to.be(LEFT);
      });
  
      it('above and left for northwest', function () {
        const rel = _ol_extent_.coordinateRelationship(extent, [-190, 100]);
        expect(rel & ABOVE).to.be(ABOVE);
        expect(rel & LEFT).to.be(LEFT);
      });
    });
  
    describe('getCenter', function () {
      it('returns the expected center', function () {
        const extent = [1, 2, 3, 4];
        const center = _ol_extent_.getCenter(extent);
        expect(center[0]).to.eql(2);
        expect(center[1]).to.eql(3);
      });
      it('returns [NaN, NaN] for empty extents', function () {
        const extent = _ol_extent_.createEmpty();
        const center = _ol_extent_.getCenter(extent);
        expect('' + center[0]).to.be('NaN');
        expect('' + center[1]).to.be('NaN');
      });
    });
  
    describe('getCorner', function () {
      const extent = [1, 2, 3, 4];
  
      it('gets the bottom left', function () {
        const corner = 'bottom-left';
        expect(_ol_extent_.getCorner(extent, corner)).to.eql([1, 2]);
      });
  
      it('gets the bottom right', function () {
        const corner = 'bottom-right';
        expect(_ol_extent_.getCorner(extent, corner)).to.eql([3, 2]);
      });
  
      it('gets the top left', function () {
        const corner = 'top-left';
        expect(_ol_extent_.getCorner(extent, corner)).to.eql([1, 4]);
      });
  
      it('gets the top right', function () {
        const corner = 'top-right';
        expect(_ol_extent_.getCorner(extent, corner)).to.eql([3, 4]);
      });
  
      it('throws exception for unexpected corner', function () {
        expect(function () {
          _ol_extent_.getCorner(extent, 'foobar');
        }).to.throwException();
      });
    });
  
    describe('getEnlargedArea', function () {
      it('returns enlarged area of two extents', function () {
        const extent1 = [-1, -1, 0, 0];
        const extent2 = [0, 0, 1, 1];
        const enlargedArea = _ol_extent_.getEnlargedArea(extent1, extent2);
        expect(enlargedArea).to.be(4);
      });
    });
  
    describe('getForViewAndSize', function () {
      it('works for a unit square', function () {
        const extent = _ol_extent_.getForViewAndSize([0, 0], 1, 0, [1, 1]);
        expect(extent[0]).to.be(-0.5);
        expect(extent[2]).to.be(0.5);
        expect(extent[1]).to.be(-0.5);
        expect(extent[3]).to.be(0.5);
      });
  
      it('works for center', function () {
        const extent = _ol_extent_.getForViewAndSize([5, 10], 1, 0, [1, 1]);
        expect(extent[0]).to.be(4.5);
        expect(extent[2]).to.be(5.5);
        expect(extent[1]).to.be(9.5);
        expect(extent[3]).to.be(10.5);
      });
  
      it('works for rotation', function () {
        const extent = _ol_extent_.getForViewAndSize([0, 0], 1, Math.PI / 4, [
          1,
          1,
        ]);
        expect(extent[0]).to.roughlyEqual(-Math.sqrt(0.5), 1e-9);
        expect(extent[2]).to.roughlyEqual(Math.sqrt(0.5), 1e-9);
        expect(extent[1]).to.roughlyEqual(-Math.sqrt(0.5), 1e-9);
        expect(extent[3]).to.roughlyEqual(Math.sqrt(0.5), 1e-9);
      });
  
      it('works for resolution', function () {
        const extent = _ol_extent_.getForViewAndSize([0, 0], 2, 0, [1, 1]);
        expect(extent[0]).to.be(-1);
        expect(extent[2]).to.be(1);
        expect(extent[1]).to.be(-1);
        expect(extent[3]).to.be(1);
      });
  
      it('works for size', function () {
        const extent = _ol_extent_.getForViewAndSize([0, 0], 1, 0, [10, 5]);
        expect(extent[0]).to.be(-5);
        expect(extent[2]).to.be(5);
        expect(extent[1]).to.be(-2.5);
        expect(extent[3]).to.be(2.5);
      });
    });
  
    describe('getSize', function () {
      it('returns the expected size', function () {
        const extent = [0, 1, 2, 4];
        const size = _ol_extent_.getSize(extent);
        expect(size).to.eql([2, 3]);
      });
    });
  
    describe('getIntersectionArea', function () {
      it('returns correct area when extents intersect', function () {
        const extent1 = [0, 0, 2, 2];
        const extent2 = [1, 1, 3, 3];
        const intersectionArea = _ol_extent_.getIntersectionArea(
          extent1,
          extent2
        );
        expect(intersectionArea).to.be(1);
      });
      it('returns 0 when extents do not intersect', function () {
        const extent1 = [0, 0, 1, 1];
        const extent2 = [2, 2, 3, 3];
        const intersectionArea = _ol_extent_.getIntersectionArea(
          extent1,
          extent2
        );
        expect(intersectionArea).to.be(0);
      });
    });
  
    describe('getMargin', function () {
      it('returns the correct margin (sum of width and height)', function () {
        const extent = [1, 2, 3, 4];
        expect(_ol_extent_.getMargin(extent)).to.be(4);
      });
    });
  
    describe('intersects', function () {
      it('returns the expected value', function () {
        const intersects = _ol_extent_.intersects;
        const extent = [50, 50, 100, 100];
        expect(intersects(extent, extent)).to.be(true);
        expect(intersects(extent, [20, 20, 80, 80])).to.be(true);
        expect(intersects(extent, [20, 50, 80, 100])).to.be(true);
        expect(intersects(extent, [20, 80, 80, 120])).to.be(true);
        expect(intersects(extent, [50, 20, 100, 80])).to.be(true);
        expect(intersects(extent, [50, 80, 100, 120])).to.be(true);
        expect(intersects(extent, [80, 20, 120, 80])).to.be(true);
        expect(intersects(extent, [80, 50, 120, 100])).to.be(true);
        expect(intersects(extent, [80, 80, 120, 120])).to.be(true);
        expect(intersects(extent, [20, 20, 120, 120])).to.be(true);
        expect(intersects(extent, [70, 70, 80, 80])).to.be(true);
        expect(intersects(extent, [10, 10, 30, 30])).to.be(false);
        expect(intersects(extent, [30, 10, 70, 30])).to.be(false);
        expect(intersects(extent, [50, 10, 100, 30])).to.be(false);
        expect(intersects(extent, [80, 10, 120, 30])).to.be(false);
        expect(intersects(extent, [120, 10, 140, 30])).to.be(false);
        expect(intersects(extent, [10, 30, 30, 70])).to.be(false);
        expect(intersects(extent, [120, 30, 140, 70])).to.be(false);
        expect(intersects(extent, [10, 50, 30, 100])).to.be(false);
        expect(intersects(extent, [120, 50, 140, 100])).to.be(false);
        expect(intersects(extent, [10, 80, 30, 120])).to.be(false);
        expect(intersects(extent, [120, 80, 140, 120])).to.be(false);
        expect(intersects(extent, [10, 120, 30, 140])).to.be(false);
        expect(intersects(extent, [30, 120, 70, 140])).to.be(false);
        expect(intersects(extent, [50, 120, 100, 140])).to.be(false);
        expect(intersects(extent, [80, 120, 120, 140])).to.be(false);
        expect(intersects(extent, [120, 120, 140, 140])).to.be(false);
      });
    });
  
    describe('scaleFromCenter', function () {
      it('scales the extent from its center', function () {
        const extent = [1, 1, 3, 3];
        _ol_extent_.scaleFromCenter(extent, 2);
        expect(extent[0]).to.eql(0);
        expect(extent[2]).to.eql(4);
        expect(extent[1]).to.eql(0);
        expect(extent[3]).to.eql(4);
      });
    });
  
    describe('intersectsSegment()', function () {
      const extent = [-180, -90, 180, 90];
      const north = [0, 100];
      const northeast = [190, 100];
      const east = [190, 0];
      const southeast = [190, -100];
      const south = [0, -100];
      const southwest = [-190, -100];
      const west = [-190, 0];
      const northwest = [-190, 100];
      const center = [0, 0];
      const top = [0, 90];
      const right = [180, 0];
      const bottom = [-90, 0];
      const left = [-180, 0];
      const inside = [10, 10];
  
      it('returns true if contained', function () {
        const intersects = _ol_extent_.intersectsSegment(extent, center, inside);
        expect(intersects).to.be(true);
      });
  
      it('returns true if crosses top', function () {
        const intersects = _ol_extent_.intersectsSegment(extent, center, north);
        expect(intersects).to.be(true);
      });
  
      it('returns true if crosses right', function () {
        const intersects = _ol_extent_.intersectsSegment(extent, center, east);
        expect(intersects).to.be(true);
      });
  
      it('returns true if crosses bottom', function () {
        const intersects = _ol_extent_.intersectsSegment(extent, center, south);
        expect(intersects).to.be(true);
      });
  
      it('returns true if crosses left', function () {
        const intersects = _ol_extent_.intersectsSegment(extent, center, west);
        expect(intersects).to.be(true);
      });
  
      it('returns false if above', function () {
        const intersects = _ol_extent_.intersectsSegment(
          extent,
          northwest,
          north
        );
        expect(intersects).to.be(false);
      });
  
      it('returns false if right', function () {
        const intersects = _ol_extent_.intersectsSegment(extent, northeast, east);
        expect(intersects).to.be(false);
      });
  
      it('returns false if below', function () {
        const intersects = _ol_extent_.intersectsSegment(
          extent,
          south,
          southwest
        );
        expect(intersects).to.be(false);
      });
  
      it('returns false if left', function () {
        const intersects = _ol_extent_.intersectsSegment(extent, west, southwest);
        expect(intersects).to.be(false);
      });
  
      it('returns true if crosses top to bottom', function () {
        const intersects = _ol_extent_.intersectsSegment(extent, north, south);
        expect(intersects).to.be(true);
      });
  
      it('returns true if crosses bottom to top', function () {
        const intersects = _ol_extent_.intersectsSegment(extent, south, north);
        expect(intersects).to.be(true);
      });
  
      it('returns true if crosses left to right', function () {
        const intersects = _ol_extent_.intersectsSegment(extent, west, east);
        expect(intersects).to.be(true);
      });
  
      it('returns true if crosses right to left', function () {
        const intersects = _ol_extent_.intersectsSegment(extent, east, west);
        expect(intersects).to.be(true);
      });
  
      it('returns true if crosses northwest to east', function () {
        const intersects = _ol_extent_.intersectsSegment(extent, northwest, east);
        expect(intersects).to.be(true);
      });
  
      it('returns true if crosses south to west', function () {
        const intersects = _ol_extent_.intersectsSegment(extent, south, west);
        expect(intersects).to.be(true);
      });
  
      it('returns true if touches top', function () {
        const intersects = _ol_extent_.intersectsSegment(extent, northwest, top);
        expect(intersects).to.be(true);
      });
  
      it('returns true if touches right', function () {
        const intersects = _ol_extent_.intersectsSegment(
          extent,
          southeast,
          right
        );
        expect(intersects).to.be(true);
      });
  
      it('returns true if touches bottom', function () {
        const intersects = _ol_extent_.intersectsSegment(extent, bottom, south);
        expect(intersects).to.be(true);
      });
  
      it('returns true if touches left', function () {
        const intersects = _ol_extent_.intersectsSegment(extent, left, west);
        expect(intersects).to.be(true);
      });
  
      it('works for zero length inside', function () {
        const intersects = _ol_extent_.intersectsSegment(extent, center, center);
        expect(intersects).to.be(true);
      });
  
      it('works for zero length outside', function () {
        const intersects = _ol_extent_.intersectsSegment(extent, north, north);
        expect(intersects).to.be(false);
      });
  
      it('works for left/right intersection spanning top to bottom', function () {
        const extent = [2, 1, 3, 4];
        const start = [0, 0];
        const end = [5, 5];
        expect(_ol_extent_.intersectsSegment(extent, start, end)).to.be(true);
        expect(_ol_extent_.intersectsSegment(extent, end, start)).to.be(true);
      });
  
      it('works for top/bottom intersection spanning left to right', function () {
        const extent = [1, 2, 4, 3];
        const start = [0, 0];
        const end = [5, 5];
        expect(_ol_extent_.intersectsSegment(extent, start, end)).to.be(true);
        expect(_ol_extent_.intersectsSegment(extent, end, start)).to.be(true);
      });
    });
  
    describe('#applyTransform()', function () {
      it('does transform', function () {
        const transformFn = getTransform('EPSG:4326', 'EPSG:3857');
        const sourceExtent = [-15, -30, 45, 60];
        const destinationExtent = _ol_extent_.applyTransform(
          sourceExtent,
          transformFn
        );
        expect(destinationExtent).not.to.be(undefined);
        expect(destinationExtent).not.to.be(null);
        // FIXME check values with third-party tool
        expect(destinationExtent[0]).to.roughlyEqual(-1669792.3618991037, 1e-9);
        expect(destinationExtent[2]).to.roughlyEqual(5009377.085697311, 1e-9);
        expect(destinationExtent[1]).to.roughlyEqual(-3503549.843504376, 1e-8);
        expect(destinationExtent[3]).to.roughlyEqual(8399737.889818361, 1e-8);
      });
  
      it('takes arbitrary function', function () {
        const transformFn = function (input, output, opt_dimension) {
          const dimension = opt_dimension !== undefined ? opt_dimension : 2;
          if (output === undefined) {
            output = new Array(input.length);
          }
          const n = input.length;
          let i;
          for (i = 0; i < n; i += dimension) {
            output[i] = -input[i];
            output[i + 1] = -input[i + 1];
          }
          return output;
        };
        const sourceExtent = [-15, -30, 45, 60];
        const destinationExtent = _ol_extent_.applyTransform(
          sourceExtent,
          transformFn
        );
        expect(destinationExtent).not.to.be(undefined);
        expect(destinationExtent).not.to.be(null);
        expect(destinationExtent[0]).to.be(-45);
        expect(destinationExtent[2]).to.be(15);
        expect(destinationExtent[1]).to.be(-60);
        expect(destinationExtent[3]).to.be(30);
      });
  
      it('can use the stops option', function () {
        proj4.defs(
          'EPSG:32632',
          '+proj=utm +zone=32 +datum=WGS84 +units=m +no_defs'
        );
        register(proj4);
        const transformFn = getTransform('EPSG:4326', 'EPSG:32632');
        const sourceExtentN = [6, 0, 12, 84];
        const destinationExtentN = _ol_extent_.applyTransform(
          sourceExtentN,
          transformFn
        );
        expect(destinationExtentN).not.to.be(undefined);
        expect(destinationExtentN).not.to.be(null);
        expect(destinationExtentN[0]).to.roughlyEqual(166021.44308053964, 1e-8);
        expect(destinationExtentN[2]).to.roughlyEqual(833978.5569194605, 1e-8);
        expect(destinationExtentN[1]).to.roughlyEqual(0, 1e-8);
        expect(destinationExtentN[3]).to.roughlyEqual(9329005.182447437, 1e-8);
        const sourceExtentNS = [6, -84, 12, 84];
        const destinationExtentNS = _ol_extent_.applyTransform(
          sourceExtentNS,
          transformFn
        );
        expect(destinationExtentNS).not.to.be(undefined);
        expect(destinationExtentNS).not.to.be(null);
        expect(destinationExtentNS[0]).to.roughlyEqual(465005.34493886377, 1e-8);
        expect(destinationExtentNS[2]).to.roughlyEqual(534994.6550611362, 1e-8);
        expect(destinationExtentNS[1]).to.roughlyEqual(
          -destinationExtentN[3],
          1e-8
        );
        expect(destinationExtentNS[3]).to.roughlyEqual(
          destinationExtentN[3],
          1e-8
        );
        const destinationExtentNS2 = _ol_extent_.applyTransform(
          sourceExtentNS,
          transformFn,
          undefined,
          2
        );
        expect(destinationExtentNS2).not.to.be(undefined);
        expect(destinationExtentNS2).not.to.be(null);
        expect(destinationExtentNS2[0]).to.roughlyEqual(
          destinationExtentN[0],
          1e-8
        );
        expect(destinationExtentNS2[2]).to.roughlyEqual(
          destinationExtentN[2],
          1e-8
        );
        expect(destinationExtentNS2[1]).to.roughlyEqual(
          -destinationExtentN[3],
          1e-8
        );
        expect(destinationExtentNS2[3]).to.roughlyEqual(
          destinationExtentN[3],
          1e-8
        );
      });
    });
  
    describe('wrapX()', function () {
      const projection = get('EPSG:4326');
  
      it('leaves real world extent untouched', function () {
        expect(_ol_extent_.wrapX([16, 48, 18, 49], projection)).to.eql([
          16,
          48,
          18,
          49,
        ]);
      });
  
      it('moves left world extent to real world', function () {
        expect(_ol_extent_.wrapX([-344, 48, -342, 49], projection)).to.eql([
          16,
          48,
          18,
          49,
        ]);
      });
  
      it('moves right world extent to real world', function () {
        expect(_ol_extent_.wrapX([376, 48, 378, 49], projection)).to.eql([
          16,
          48,
          18,
          49,
        ]);
      });
  
      it('moves far off left extent to real world', function () {
        expect(_ol_extent_.wrapX([-1064, 48, -1062, 49], projection)).to.eql([
          16,
          48,
          18,
          49,
        ]);
      });
  
      it('moves far off right extent to real world', function () {
        expect(_ol_extent_.wrapX([1096, 48, 1098, 49], projection)).to.eql([
          16,
          48,
          18,
          49,
        ]);
      });
  
      it('leaves -180 crossing extent with real world center untouched', function () {
        expect(_ol_extent_.wrapX([-184, 48, 16, 49], projection)).to.eql([
          -184,
          48,
          16,
          49,
        ]);
      });
  
      it('moves +180 crossing extent with off-world center to the real world', function () {
        expect(_ol_extent_.wrapX([300, 48, 376, 49], projection)).to.eql([
          -60,
          48,
          16,
          49,
        ]);
      });
  
      it('produces the same real world extent for shifted extents with center at +/-180', function () {
        expect(_ol_extent_.wrapX([360, -90, 720, 90], projection)).to.eql([
          -360,
          -90,
          0,
          90,
        ]);
        expect(_ol_extent_.wrapX([0, -90, 360, 90], projection)).to.eql([
          -360,
          -90,
          0,
          90,
        ]);
        expect(_ol_extent_.wrapX([-360, -90, 0, 90], projection)).to.eql([
          -360,
          -90,
          0,
          90,
        ]);
      });
    });
  
    describe('approximatelyEquals', function () {
      it('returns true when within tolerance', function () {
        expect(
          _ol_extent_.approximatelyEquals(
            [16, 48, 17, 49],
            [16.09, 48, 17, 49],
            0.1
          )
        ).to.be(true);
      });
      it('returns false when not within tolerance', function () {
        expect(
          _ol_extent_.approximatelyEquals(
            [16, 48, 17, 49],
            [16.11, 48, 17, 49],
            0.1
          )
        ).to.be(false);
      });
    });
  });
  