// You can do this in the grunt config for each mocha task, see the `options` config


// Start the main app logic.

function startTests(chai, proj4, testPoints) {


  var assert = chai.assert;
  proj4.defs([
    ["EPSG:102018", "+proj=gnom +lat_0=90 +lon_0=0 +x_0=6300000 +y_0=6300000 +ellps=WGS84 +datum=WGS84 +units=m +no_defs"],
    ["testmerc", "+proj=merc +lon_0=5.937 +lat_ts=45.027 +ellps=sphere"],
    ["testmerc2", "+proj=merc +a=6378137 +b=6378137 +lat_ts=0.0 +lon_0=0.0 +x_0=0.0 +y_0=0 +units=m +k=1.0 +nadgrids=@null +no_defs"]
  ]);
  proj4.defs('esriOnline', 'PROJCS["WGS_1984_Web_Mercator_Auxiliary_Sphere",GEOGCS["GCS_WGS_1984",DATUM["D_WGS_1984",SPHEROID["WGS_1984",6378137.0,298.257223563]],PRIMEM["Greenwich",0.0],UNIT["Degree",0.0174532925199433]],PROJECTION["Mercator_Auxiliary_Sphere"],PARAMETER["False_Easting",0.0],PARAMETER["False_Northing",0.0],PARAMETER["Central_Meridian",0.0],PARAMETER["Standard_Parallel_1",0.0],PARAMETER["Auxiliary_Sphere_Type",0.0],UNIT["Meter",1.0]]');

  describe('parse', function() {
    it('should parse units', function() {
      assert.equal(proj4.defs('testmerc2').units, 'm');
    });
  });

  describe('proj2proj', function() {
    it('should work transforming from one projection to another', function() {
      var sweref99tm = '+proj=utm +zone=33 +ellps=GRS80 +towgs84=0,0,0,0,0,0,0 +units=m +no_defs';
      var rt90 = '+lon_0=15.808277777799999 +lat_0=0.0 +k=1.0 +x_0=1500000.0 +y_0=0.0 +proj=tmerc +ellps=bessel +units=m +towgs84=414.1,41.3,603.1,-0.855,2.141,-7.023,0 +no_defs';
      var rslt = proj4(sweref99tm, rt90).forward([319180, 6399862]);
      assert.closeTo(rslt[0], 1271137.927561178, 0.000001);
      assert.closeTo(rslt[1], 6404230.291456626, 0.000001);
    });
    it('should work with a proj object', function() {
      var sweref99tm = proj4('+proj=utm +zone=33 +ellps=GRS80 +towgs84=0,0,0,0,0,0,0 +units=m +no_defs');
      var rt90 = proj4('+lon_0=15.808277777799999 +lat_0=0.0 +k=1.0 +x_0=1500000.0 +y_0=0.0 +proj=tmerc +ellps=bessel +units=m +towgs84=414.1,41.3,603.1,-0.855,2.141,-7.023,0 +no_defs');
      var rslt = proj4(sweref99tm, rt90).forward([319180, 6399862]);
      assert.closeTo(rslt[0], 1271137.927561178, 0.000001);
      assert.closeTo(rslt[1], 6404230.291456626, 0.000001);
    });
  });

  describe('proj4', function() {
    describe('core', function() {
      testPoints.forEach(function(testPoint) {
        describe(testPoint.code, function() {
          var xyAcc = 2,
            llAcc = 6;
          if ('acc' in testPoint) {
            if ('xy' in testPoint.acc) {
              xyAcc = testPoint.acc.xy;
            }
            if ('ll' in testPoint.acc) {
              llAcc = testPoint.acc.ll;
            }
          }
          var xyEPSLN = Math.pow(10, - 1 * xyAcc);
          var llEPSLN = Math.pow(10, - 1 * llAcc);
          describe('traditional', function() {
            it('should work with forwards', function() {
              var proj = new proj4.Proj(testPoint.code);
              var xy = proj4.transform(proj4.WGS84, proj, proj4.toPoint(testPoint.ll));
              assert.closeTo(xy.x, testPoint.xy[0], xyEPSLN, 'x is close');
              assert.closeTo(xy.y, testPoint.xy[1], xyEPSLN, 'y is close');
            });
            it('should work with backwards', function() {
              var proj = new proj4.Proj(testPoint.code);
              var ll = proj4.transform(proj, proj4.WGS84, proj4.toPoint(testPoint.xy));
              assert.closeTo(ll.x, testPoint.ll[0], llEPSLN, 'lng is close');
              assert.closeTo(ll.y, testPoint.ll[1], llEPSLN, 'lat is close');
            });
          });
          describe('new method 2 param', function() {
            it('shortcut method should work with an array', function() {
              var xy = proj4(testPoint.code, testPoint.ll);
              assert.closeTo(xy[0], testPoint.xy[0], xyEPSLN, 'x is close');
              assert.closeTo(xy[1], testPoint.xy[1], xyEPSLN, 'y is close');
            });
            it('shortcut method should work with an object', function() {
              var pt = {
                x: testPoint.ll[0],
                y: testPoint.ll[1]
              };
              var xy = proj4(testPoint.code, pt);
              assert.closeTo(xy.x, testPoint.xy[0], xyEPSLN, 'x is close');
              assert.closeTo(xy.y, testPoint.xy[1], xyEPSLN, 'y is close');
            });
            it('shortcut method should work with a point object', function() {
              var pt = proj4.toPoint(testPoint.ll);
              var xy = proj4(testPoint.code, pt);
              assert.closeTo(xy.x, testPoint.xy[0], xyEPSLN, 'x is close');
              assert.closeTo(xy.y, testPoint.xy[1], xyEPSLN, 'y is close');
            });
          });
          describe('new method 3 param', function() {
            it('shortcut method should work with an array', function() {
              var xy = proj4(proj4.WGS84, testPoint.code, testPoint.ll);
              assert.closeTo(xy[0], testPoint.xy[0], xyEPSLN, 'x is close');
              assert.closeTo(xy[1], testPoint.xy[1], xyEPSLN, 'y is close');
            });
            it('shortcut method should work with an object', function() {
              var pt = {
                x: testPoint.ll[0],
                y: testPoint.ll[1]
              };
              var xy = proj4(proj4.WGS84, testPoint.code, pt);
              assert.closeTo(xy.x, testPoint.xy[0], xyEPSLN, 'x is close');
              assert.closeTo(xy.y, testPoint.xy[1], xyEPSLN, 'y is close');
            });
            it('shortcut method should work with a point object', function() {
              var pt = proj4.toPoint(testPoint.ll);
              var xy = proj4(proj4.WGS84, testPoint.code, pt);
              assert.closeTo(xy.x, testPoint.xy[0], xyEPSLN, 'x is close');
              assert.closeTo(xy.y, testPoint.xy[1], xyEPSLN, 'y is close');
            });
          });
          describe('new method 3 param other way', function() {
            it('shortcut method should work with an array', function() {
              var ll = proj4(testPoint.code, proj4.WGS84, testPoint.xy);
              assert.closeTo(ll[0], testPoint.ll[0], llEPSLN, 'x is close');
              assert.closeTo(ll[1], testPoint.ll[1], llEPSLN, 'y is close');
            });
            it('shortcut method should work with an object', function() {
              var pt = {
                x: testPoint.xy[0],
                y: testPoint.xy[1]
              };
              // in case of geocentric proj we need Z value.
              if (typeof testPoint.xy[2] === 'number') {
                pt.z = testPoint.xy[2]
              }
              var ll = proj4(testPoint.code, proj4.WGS84, pt);
              assert.closeTo(ll.x, testPoint.ll[0], llEPSLN, 'x is close');
              assert.closeTo(ll.y, testPoint.ll[1], llEPSLN, 'y is close');
            });
            it('shortcut method should work with a point object', function() {
              var pt = proj4.toPoint(testPoint.xy);
              var ll = proj4(testPoint.code, proj4.WGS84, pt);
              assert.closeTo(ll.x, testPoint.ll[0], llEPSLN, 'x is close');
              assert.closeTo(ll.y, testPoint.ll[1], llEPSLN, 'y is close');
            });
          });
          describe('1 param', function() {
            it('forwards', function() {
              var xy = proj4(testPoint.code).forward(testPoint.ll);
              assert.closeTo(xy[0], testPoint.xy[0], xyEPSLN, 'x is close');
              assert.closeTo(xy[1], testPoint.xy[1], xyEPSLN, 'y is close');
            });
            it('inverse', function() {
              var ll = proj4(testPoint.code).inverse(testPoint.xy);
              assert.closeTo(ll[0], testPoint.ll[0], llEPSLN, 'x is close');
              assert.closeTo(ll[1], testPoint.ll[1], llEPSLN, 'y is close');
            });
          });
          describe('proj object', function() {
            it('should work with a 2 element array', function() {
              const ll = [testPoint.ll[0], testPoint.ll[1]];
              Object.freeze(ll);
              var xy = proj4(new proj4.Proj(testPoint.code), ll);
              assert.closeTo(xy[0], testPoint.xy[0], xyEPSLN, 'x is close');
              assert.closeTo(xy[1], testPoint.xy[1], xyEPSLN, 'y is close');
            });
            it('should work wit a 3 element array', function() {
              const llz = [testPoint.ll[0], testPoint.ll[1], 0];
              Object.freeze(llz);
              var xy = proj4(new proj4.Proj(testPoint.code), llz);
              assert.closeTo(xy[0], testPoint.xy[0], xyEPSLN, 'x is close');
              assert.closeTo(xy[1], testPoint.xy[1], xyEPSLN, 'y is close');
            });
            it('should work on element', function() {
              var xy = proj4(new proj4.Proj(testPoint.code)).forward(testPoint.ll);
              assert.closeTo(xy[0], testPoint.xy[0], xyEPSLN, 'x is close');
              assert.closeTo(xy[1], testPoint.xy[1], xyEPSLN, 'y is close');
            });
            it('should work 3 element point object', function() {
              var pt = proj4.toPoint(testPoint.xy);
              var ll = proj4(new proj4.Proj(testPoint.code), proj4.WGS84, pt);
              assert.closeTo(ll.x, testPoint.ll[0], llEPSLN, 'x is close');
              assert.closeTo(ll.y, testPoint.ll[1], llEPSLN, 'y is close');
            });
          });
          describe('proj coord object', function() {
            it('should not be modified', function() {
              var expected = {x: 100000, y: 100000};
              var inpxy = {x: expected.x, y: expected.y};
              proj4('EPSG:3857', proj4.WGS84, inpxy);

              assert.deepEqual(inpxy, expected, "input is unmodified");
            });
          });
        });
      });
    });
    describe('points', function () {
      it('should not create a z if none was provided', function() {
        const result = proj4(
          'GEOGCS["WGS 84",DATUM["WGS_1984",SPHEROID["WGS 84",6378137,298.257223563,AUTHORITY["EPSG","7030"]],AUTHORITY["EPSG","6326"]],PRIMEM["Greenwich",0,AUTHORITY["EPSG","8901"]],UNIT["degree",0.01745329251994328,AUTHORITY["EPSG","9122"]],AUTHORITY["EPSG","4326"]]',
          'PROJCS["OSGB 1936 / British National Grid",GEOGCS["OSGB 1936",DATUM["OSGB_1936",SPHEROID["Airy 1830",6377563.396,299.3249646,AUTHORITY["EPSG","7001"]],AUTHORITY["EPSG","6277"]],PRIMEM["Greenwich",0,AUTHORITY["EPSG","8901"]],UNIT["degree",0.01745329251994328,AUTHORITY["EPSG","9122"]],AUTHORITY["EPSG","4277"]],UNIT["metre",1,AUTHORITY["EPSG","9001"]],PROJECTION["Transverse_Mercator"],PARAMETER["latitude_of_origin",49],PARAMETER["central_meridian",-2],PARAMETER["scale_factor",0.9996012717],PARAMETER["false_easting",400000],PARAMETER["false_northing",-100000],AUTHORITY["EPSG","27700"],AXIS["Easting",EAST],AXIS["Northing",NORTH]]',
          {x: -0.12793738, y: 51.507747});
        assert.closeTo(result.x, 530018.229301635, 1e-6);
        assert.closeTo(result.y, 180418.4380560551, 1e-6);
        assert.equal(result.z, undefined);
      });
      it('should return null for transform of [0, 0] for EPSG:3413 -> EPSG:3857', function () {
        var point = proj4.transform(
          proj4.Proj('+proj=stere +lat_0=90 +lat_ts=70 +lon_0=-45 +k=1 +x_0=0 +y_0=0 +datum=WGS84 +units=m +no_defs'),
          proj4.Proj('EPSG:3857'),
          [0, 0]
        );
        assert.strictEqual(point, null);
      });
      it('should ignore stuff it does not know', function () {
        var sweref99tm = '+proj=utm +zone=33 +ellps=GRS80 +towgs84=0,0,0,0,0,0,0 +units=m +no_defs';
        var rt90 = '+lon_0=15.808277777799999 +lat_0=0.0 +k=1.0 +x_0=1500000.0 +y_0=0.0 +proj=tmerc +ellps=bessel +units=m +towgs84=414.1,41.3,603.1,-0.855,2.141,-7.023,0 +no_defs';
        var rslt = proj4(sweref99tm, rt90).forward({
          x: 319180,
          y: 6399862,
          z: 0,
          m: 1000,
          method: function () {
            return 'correct answer';
          }
        });
        assert.closeTo(rslt.x, 1271137.927561178, 0.000001);
        assert.closeTo(rslt.y, 6404230.291456626, 0.000001);
        assert.equal(rslt.z, 0);
        assert.equal(rslt.m, 1000);
        assert.equal(rslt.method(), 'correct answer');
      });
      it('should be able to compute X Y Z M in geocenteric coordinates', function () {
        var epsg4978 = '+proj=geocent +datum=WGS84 +units=m +no_defs';
        var rslt = proj4(epsg4978).forward({
          x: -7.76166,
          y: 39.19685,
          z: 0,
          m: 1000,
          method: function () {
            return 'correct answer';
          }
        });
        assert.closeTo(rslt.x, 4904199.584207411, 0.000001);
        assert.closeTo(rslt.y, -668448.8153664203, 0.000001);
        assert.closeTo(rslt.z, 4009276.930771821, 0.000001);
        assert.equal(rslt.m, 1000);
        assert.equal(rslt.method(), 'correct answer');
      });
    });
    describe('points array', function () {
      it('should ignore stuff it does not know', function () {
        var sweref99tm = '+proj=utm +zone=33 +ellps=GRS80 +towgs84=0,0,0,0,0,0,0 +units=m +no_defs';
        var rt90 = '+lon_0=15.808277777799999 +lat_0=0.0 +k=1.0 +x_0=1500000.0 +y_0=0.0 +proj=tmerc +ellps=bessel +units=m +towgs84=414.1,41.3,603.1,-0.855,2.141,-7.023,0 +no_defs';
        var rslt = proj4(sweref99tm, rt90).forward([
          319180,
          6399862,
          0,
          1000,
        ]);
        assert.closeTo(rslt[0], 1271137.927561178, 0.000001);
        assert.closeTo(rslt[1], 6404230.291456626, 0.000001);
        assert.equal(rslt[2], 0);
        assert.equal(rslt[3], 1000);
      });
      it('should be able to compute X Y Z M in geocenteric coordinates', function () {
        var epsg4978 = '+proj=geocent +datum=WGS84 +units=m +no_defs';
        var rslt = proj4(epsg4978).forward([
          -7.76166,
          39.19685,
          0,
          1000
        ]);
        assert.closeTo(rslt[0], 4904199.584207411, 0.000001);
        assert.closeTo(rslt[1], -668448.8153664203, 0.000001);
        assert.closeTo(rslt[2], 4009276.930771821, 0.000001);
        assert.equal(rslt[3], 1000);
      });
    });

    it('should use [x,y] axis order', function() {
      var enu = 'PROJCS["NAD83 / Massachusetts Mainland", GEOGCS["NAD83", DATUM["North American Datum 1983", SPHEROID["GRS 1980", 6378137.0, 298.257222101, AUTHORITY["EPSG","7019"]], TOWGS84[0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0], AUTHORITY["EPSG","6269"]], PRIMEM["Greenwich", 0.0, AUTHORITY["EPSG","8901"]], UNIT["degree", 0.017453292519943295], AXIS["Geodetic longitude", EAST], AXIS["Geodetic latitude", NORTH], AUTHORITY["EPSG","4269"]], PROJECTION["Lambert_Conformal_Conic_2SP", AUTHORITY["EPSG","9802"]], PARAMETER["central_meridian", -71.5], PARAMETER["latitude_of_origin", 41.0], PARAMETER["standard_parallel_1", 42.68333333333334], PARAMETER["false_easting", 200000.0], PARAMETER["false_northing", 750000.0], PARAMETER["scale_factor", 1.0], PARAMETER["standard_parallel_2", 41.71666666666667], UNIT["m", 1.0], AXIS["Easting", EAST], AXIS["Northing", NORTH], AUTHORITY["EPSG","26986"]]';
      var neu = 'PROJCS["NAD83 / Massachusetts Mainland NE", GEOGCS["NAD83", DATUM["North American Datum 1983", SPHEROID["GRS 1980", 6378137.0, 298.257222101, AUTHORITY["EPSG","7019"]], TOWGS84[0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0], AUTHORITY["EPSG","6269"]], PRIMEM["Greenwich", 0.0, AUTHORITY["EPSG","8901"]], UNIT["degree", 0.017453292519943295], AXIS["Geodetic latitude", NORTH], AXIS["Geodetic longitude", EAST], AUTHORITY["EPSG","4269"]], PROJECTION["Lambert_Conformal_Conic_2SP", AUTHORITY["EPSG","9802"]], PARAMETER["central_meridian", -71.5], PARAMETER["latitude_of_origin", 41.0], PARAMETER["standard_parallel_1", 42.68333333333334], PARAMETER["false_easting", 200000.0], PARAMETER["false_northing", 750000.0], PARAMETER["scale_factor", 1.0], PARAMETER["standard_parallel_2", 41.71666666666667], UNIT["m", 1.0], AXIS["Northing", NORTH], AXIS["Easting", EAST], AUTHORITY["EPSG","26986"]]';
      var rslt = proj4(enu, neu).forward({
        x: 10.2,
        y: 43.4
      });
      assert.closeTo(rslt.x, 10.2, 0.000001);
      assert.closeTo(rslt.y, 43.4, 0.000001);
    });

    it('should use correct axis order with proj4.transform()', function() {
      var enu = 'PROJCS["NAD83 / Massachusetts Mainland", GEOGCS["NAD83", DATUM["North American Datum 1983", SPHEROID["GRS 1980", 6378137.0, 298.257222101, AUTHORITY["EPSG","7019"]], TOWGS84[0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0], AUTHORITY["EPSG","6269"]], PRIMEM["Greenwich", 0.0, AUTHORITY["EPSG","8901"]], UNIT["degree", 0.017453292519943295], AXIS["Geodetic longitude", EAST], AXIS["Geodetic latitude", NORTH], AUTHORITY["EPSG","4269"]], PROJECTION["Lambert_Conformal_Conic_2SP", AUTHORITY["EPSG","9802"]], PARAMETER["central_meridian", -71.5], PARAMETER["latitude_of_origin", 41.0], PARAMETER["standard_parallel_1", 42.68333333333334], PARAMETER["false_easting", 200000.0], PARAMETER["false_northing", 750000.0], PARAMETER["scale_factor", 1.0], PARAMETER["standard_parallel_2", 41.71666666666667], UNIT["m", 1.0], AXIS["Easting", EAST], AXIS["Northing", NORTH], AUTHORITY["EPSG","26986"]]';
      var neu = 'PROJCS["NAD83 / Massachusetts Mainland NE", GEOGCS["NAD83", DATUM["North American Datum 1983", SPHEROID["GRS 1980", 6378137.0, 298.257222101, AUTHORITY["EPSG","7019"]], TOWGS84[0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0], AUTHORITY["EPSG","6269"]], PRIMEM["Greenwich", 0.0, AUTHORITY["EPSG","8901"]], UNIT["degree", 0.017453292519943295], AXIS["Geodetic latitude", NORTH], AXIS["Geodetic longitude", EAST], AUTHORITY["EPSG","4269"]], PROJECTION["Lambert_Conformal_Conic_2SP", AUTHORITY["EPSG","9802"]], PARAMETER["central_meridian", -71.5], PARAMETER["latitude_of_origin", 41.0], PARAMETER["standard_parallel_1", 42.68333333333334], PARAMETER["false_easting", 200000.0], PARAMETER["false_northing", 750000.0], PARAMETER["scale_factor", 1.0], PARAMETER["standard_parallel_2", 41.71666666666667], UNIT["m", 1.0], AXIS["Northing", NORTH], AXIS["Easting", EAST], AUTHORITY["EPSG","26986"]]';
      var rslt = proj4(enu, neu).forward({
        x: 10.2,
        y: 43.4
      }, true);
      assert.closeTo(rslt.x, 43.4, 0.000001);
      assert.closeTo(rslt.y, 10.2, 0.000001);
    });

    it('axes should be invertable with proj4.transform()', function () {
      var enu = '+proj=longlat +axis=enu';
      var esu = '+proj=longlat +axis=esu';
      var wnu = '+proj=longlat +axis=wnu';
      var result = proj4(enu, esu).forward({x: 40, y: 50}, true);
      assert.closeTo(result.x, 40, 0.000001);
      assert.closeTo(result.y, -50, 0.000001);
      var result = proj4(enu, wnu).forward({x: 40, y: 50}, true);
      assert.closeTo(result.x, -40, 0.000001);
      assert.closeTo(result.y, 50, 0.000001);
    });

    describe('defs', function () {
      assert.equal(proj4.defs('testmerc'), proj4.defs['testmerc']);
      proj4.defs('foo', '+proj=merc +lon_0=5.937 +lat_ts=45.027 +ellps=sphere');
      assert.typeOf(proj4.defs['foo'], 'object');
      proj4.defs('urn:x-ogc:def:crs:EPSG:4326', proj4.defs('EPSG:4326'));
      assert.strictEqual(proj4.defs['urn:x-ogc:def:crs:EPSG:4326'], proj4.defs['EPSG:4326']);

      describe('wkt', function () {
        it('should provide the correct conversion factor for WKT GEOGCS projections', function () {
          proj4.defs('EPSG:4269', 'GEOGCS["NAD83",DATUM["North_American_Datum_1983",SPHEROID["GRS 1980",6378137,298.257222101,AUTHORITY["EPSG","7019"]],AUTHORITY["EPSG","6269"]],PRIMEM["Greenwich",0,AUTHORITY["EPSG","8901"]],UNIT["degree",0.01745329251994328,AUTHORITY["EPSG","9122"]],AUTHORITY["EPSG","4269"]]');
          assert.equal(proj4.defs['EPSG:4269'].to_meter, 6378137 * 0.01745329251994328);

          proj4.defs('EPSG:4279', 'GEOGCS["OS(SN)80",DATUM["OS_SN_1980",SPHEROID["Airy 1830",6377563.396,299.3249646,AUTHORITY["EPSG","7001"]],AUTHORITY["EPSG","6279"]],PRIMEM["Greenwich",0,AUTHORITY["EPSG","8901"]],UNIT["degree",0.01745329251994328,AUTHORITY["EPSG","9122"]],AUTHORITY["EPSG","4279"]]');
          assert.equal(proj4.defs['EPSG:4279'].to_meter, 6377563.396 * 0.01745329251994328);
        });
        it('should parse wkt and proj4 of the same crs and result in the same params', function () {
          var s1 = 'GEOGCS["PSD93",DATUM["PDO_Survey_Datum_1993",SPHEROID["Clarke 1880 (RGS)",6378249.145,293.465,AUTHORITY["EPSG","7012"]],TOWGS84[-180.624,-225.516,173.919,-0.81,-1.898,8.336,16.7101],AUTHORITY["EPSG","6134"]],PRIMEM["Greenwich",0,AUTHORITY["EPSG","8901"]],UNIT["degree",0.0174532925199433,AUTHORITY["EPSG","9122"]],AUTHORITY["EPSG","4134"]]';
          var s2 = '+proj=longlat +ellps=clrk80 +towgs84=-180.624,-225.516,173.919,-0.81,-1.898,8.336,16.7101 +no_defs';
          var crs1 = proj4(s1);
          var crs2 = proj4(s2);
          assert.equal(crs1.oProj.a, crs2.oProj.a);
          // proj4 has different ellipsoid parameters that EPSG: http://epsg.io/4134
          // assert.equal(crs1.oProj.b, crs2.oProj.b);
        });
        it('should handled defined points correctly', function () {
          var prj = '+proj=utm +zone=31';
          var proj = proj4(prj);
          var res = proj.forward([3, 0]);
          assert.deepEqual(res, [500000, 0]);
        });
      });
    });
    describe('errors', function() {
      it('should throw an error for an unknown ref', function() {
        assert.throws(function() {
          new proj4.Proj('fake one');
        }, 'fake one', 'should work');
      });
      it('should throw when passed null', function() {
        assert.throws(function() {
            proj4('+proj=utm +zone=31', [null, 0]);
        }, 'coordinates must be finite numbers', 'should work');
      });
      it('should throw when passed NaN', function() {
        assert.throws(function() {
            proj4('+proj=utm +zone=31', [0, NaN]);
        }, 'coordinates must be finite numbers', 'should work');
      });
      it('should throw when passed Infinity', function() {
        assert.throws(function() {
            proj4('+proj=utm +zone=31', [Infinity, 0]);
        }, 'coordinates must be finite numbers', 'should work');
      });
      it('should throw when passed -Infinity', function() {
        assert.throws(function() {
            proj4('+proj=utm +zone=31', [-Infinity, 0]);
        }, 'coordinates must be finite numbers', 'should work');
      });
    });
    describe('utility', function() {
      it('should have MGRS available in the proj4.util namespace', function() {
        assert.typeOf(proj4.mgrs, "object", "MGRS available in the proj4.util namespace");
      });
      it('should have fromMGRS method added to proj4.Point prototype', function() {
        assert.typeOf(proj4.Point.fromMGRS, "function", "fromMGRS method added to proj4.Point prototype");
      });
      it('should have toMGRS method added to proj4.Point prototype', function() {
        assert.typeOf(proj4.Point.prototype.toMGRS, "function", "toMGRS method added to proj4.Point prototype");
      });

      describe('First MGRS set', function() {
        var mgrs = "33UXP04";
        var point = proj4.Point.fromMGRS(mgrs);
        it('Longitude of point from MGRS correct.', function() {
          assert.equal(point.x.toPrecision(7), "16.41450", "Longitude of point from MGRS correct.");
        });
        it('Latitude of point from MGRS correct.', function() {
          assert.equal(point.y.toPrecision(7), "48.24949", "Latitude of point from MGRS correct.");
        });
        it('MGRS reference with highest accuracy correct.', function() {
          assert.equal(point.toMGRS(), "33UXP0500444998", "MGRS reference with highest accuracy correct.");
        });
        it('MGRS reference with 1-digit accuracy correct.', function() {
          assert.equal(point.toMGRS(1), mgrs, "MGRS reference with 1-digit accuracy correct.");
        });
      });
      describe('Second MGRS set', function() {
        var mgrs = "24XWT783908"; // near UTM zone border, so there are two ways to reference this
        var point = proj4.Point.fromMGRS(mgrs);
        it("Longitude of point from MGRS correct.", function() {
          assert.equal(point.x.toPrecision(7), "-32.66433", "Longitude of point from MGRS correct.");
        });
        it("Latitude of point from MGRS correct.", function() {
          assert.equal(point.y.toPrecision(7), "83.62778", "Latitude of point from MGRS correct.");
        });
        it("MGRS reference with 3-digit accuracy correct.", function() {
          assert.equal(point.toMGRS(3), "25XEN041865", "MGRS reference with 3-digit accuracy correct.");
        });
      });
      describe('Defs and Datum definition', function() {
        proj4.defs("EPSG:5514", "+proj=krovak +lat_0=49.5 +lon_0=24.83333333333333 +alpha=30.28813972222222 +k=0.9999 +x_0=0 +y_0=0 +ellps=bessel +pm=greenwich +units=m +no_defs +towgs84=570.8,85.7,462.8,4.998,1.587,5.261,3.56");
        var point = proj4.transform(proj4.Proj("WGS84"), proj4.Proj("EPSG:5514"),
                                proj4.toPoint([12.806988, 49.452262]));
        it("Longitude of point from WGS84 correct.", function() {
          assert.equal(point.x.toPrecision(8), "-868208.61", "Longitude of point from WGS84 correct.");
        });
        it("Latitude of point from WGS84 correct.", function() {
          assert.equal(point.y.toPrecision(9), "-1095793.64", "Latitude of point from WGS84 correct.");
        });
        var point2 = proj4.transform(proj4.Proj("WGS84"), proj4.Proj("EPSG:5514"),
                                proj4.toPoint([12.806988, 49.452262]));
        it("Longitude of point from WGS84 with second call for EPSG:5514 correct.", function() {
          assert.equal(point2.x.toPrecision(8), "-868208.61", "Longitude of point from WGS84 correct.");
        });
        it("Latitude of point from WGS84 with second call for EPSG:5514 correct.", function() {
          assert.equal(point2.y.toPrecision(9), "-1095793.64", "Latitude of point from WGS84 correct.");
        });
      });
    });

    describe('Nadgrids BETA2007', function() {
      var tests = [
        ['EPSG:31466', 'EPSG:4326', 2559552, 5670982, 6.850861772, 51.170707759, 0.0000001, 0.01],
        ['EPSG:31466', 'EPSG:3857', 2559552, 5670982, 762634.443931574, 6651545.680265270, 0.01, 0.01],
        ['EPSG:31466', 'EPSG:25832', 2559552, 5670982, 349757.381712518, 5671004.065049540, 0.01, 0.01],
      ];

      function initializeNadgrid(buffer) {
        proj4.nadgrid('BETA2007.gsb', buffer);
        proj4.defs('EPSG:31466', '+proj=tmerc +lat_0=0 +lon_0=6 +k=1 +x_0=2500000 +y_0=0 +ellps=bessel +nadgrids=BETA2007.gsb +units=m +no_defs +type=crs');
        proj4.defs('EPSG:25832', '+proj=utm +zone=32 +ellps=GRS80 +towgs84=0,0,0,0,0,0,0 +units=m +no_defs +type=crs');
      }

      before(function(done) {
        if (typeof XMLHttpRequest !== 'undefined') {
          const xhr = new XMLHttpRequest();
          xhr.open('GET', 'BETA2007.gsb', true);
          xhr.responseType = 'arraybuffer';
          xhr.addEventListener('load', function() {
            initializeNadgrid(xhr.response);
            done();
          });
          xhr.addEventListener('error', done);
          xhr.send();
        } else if (typeof require === 'function') {
          const fs = require('fs');
          const path = require('path');
          fs.readFile(path.join(__dirname, 'BETA2007.gsb'), function(err, data) {
            if (err) {
              done(err);
            } else {
              initializeNadgrid(data.buffer);
              done();
            }
          })
        }
      });

      tests.forEach(function(test) {
        var fromProj = test[0];
        var toProj = test[1];
        var fromX = test[2];
        var fromY = test[3];
        var toX = test[4];
        var toY = test[5];
        var fromPrecision = test[6];
        var toPrecision = test[7];
        it('should transform ' + fromProj + ' to ' + toProj, function () {
          var transformed = proj4(fromProj, toProj, [fromX, fromY]);
          assert.approximately(transformed[0], toX, fromPrecision);
          assert.approximately(transformed[1], toY, fromPrecision);
        });
        it('should transform ' + toProj + ' to ' + fromProj, function () {
          var transformed = proj4(toProj, fromProj, [toX, toY]);
          assert.approximately(transformed[0], fromX, toPrecision);
          assert.approximately(transformed[1], fromY, toPrecision);
        });
      });
    });

    describe('Nadgrids ntv2', function() {
      var tests = [
        [-44.382211538462, 40.3768, -44.380749, 40.377457], // just inside the lower limit
        [-87.617788, 59.623262, -87.617659, 59.623441], // just inside the upper limit
        [-44.5, 40.5, -44.498553, 40.500632], // inside the first square
        [-60, 50, -59.999192, 50.000058], // a general point towards the middle of the grid
        [0, 0, 0, 0] // fall back to null
      ];

      var converter;

      function initializeNadgrid(buffer) {
        proj4.nadgrid('ntv2', buffer);
        proj4.defs('ntv2_from', '+proj=longlat +ellps=clrk66 +nadgrids=@ignorable,ntv2,null');
        proj4.defs('ntv2_to', '+proj=longlat +datum=WGS84 +no_defs');
        converter = proj4('ntv2_from', 'ntv2_to');
      }

      before(function(done) {
        if (typeof XMLHttpRequest !== 'undefined') {
          const xhr = new XMLHttpRequest();
          xhr.open('GET', 'ntv2_0_downsampled.gsb', true);
          xhr.responseType = 'arraybuffer';
          xhr.addEventListener('load', function() {
            initializeNadgrid(xhr.response);
            done();
          });
          xhr.addEventListener('error', done);
          xhr.send();
        } else if (typeof require === 'function') {
          const fs = require('fs');
          const path = require('path');
          fs.readFile(path.join(__dirname, 'ntv2_0_downsampled.gsb'), function(err, data) {
            if (err) {
              done(err);
            } else {
              initializeNadgrid(data.buffer);
              done();
            }
          })
        }
      });

      tests.forEach(function(test) {
        var fromLng = test[0];
        var fromLat = test[1];
        var toLng = test[2];
        var toLat = test[3];
        it('should interpolate ' + [fromLng, fromLat] + ' to ' + [toLng, toLat], function () {
          var actual = converter.forward([fromLng, fromLat]);
          assert.approximately(actual[0], toLng, 0.000001);
          assert.approximately(actual[1], toLat, 0.000001);
        });
      });

      var inverseTests = [
        [-44.5, 40.5, -44.498553, 40.500632],
        [-60, 50, -59.999192, 50.000058]
      ];

      inverseTests.forEach(function(test) {
        var fromLng = test[0];
        var fromLat = test[1];
        var toLng = test[2];
        var toLat = test[3];
        it('should inverse interpolate ' + [toLng, toLat] + ' to ' + [fromLng, fromLat], function () {
          var actual = converter.inverse([toLng, toLat]);
          assert.approximately(actual[0], fromLng, 0.000001);
          assert.approximately(actual[1], fromLat, 0.000001);
        });
      });
    });
  });
}
if(typeof process !== 'undefined'&&process.toString() === '[object process]'){
  (function(){
    startTests(require('chai'), require('../dist/proj4-src'), require('./testData'));
  })();
}
