Added tests for hoveron fills to scatter jasmine test suite.

The tests rely on scatter mocks `scatter_fill_self_next`
and `scatter_fill_corner_cases` and test for a number of points
that are currently not correctly detected when hovered over
for tonexty and tozeroy fills.

Author: lumip

test/jasmine/tests/scatter_test.js

@@ -1514,6 +1514,176 @@ describe('scatter hoverPoints', function() {
     });
 });
 
+describe('scatter hoverFills', function() {
+    afterEach(destroyGraphDiv);
+
+    function _hover(gd, xval, yval, hovermode, subplotId) {
+        return gd._fullData.map(function(trace, i) {
+            var cd = gd.calcdata[i];
+            var subplot = gd._fullLayout._plots[subplotId];
+
+            var out = Scatter.hoverPoints({
+                index: false,
+                distance: 20,
+                cd: cd,
+                trace: trace,
+                xa: subplot.xaxis,
+                ya: subplot.yaxis
+            }, xval, yval, hovermode);
+
+            return Array.isArray(out) ? out[0] : null;
+        });
+    }
+
+    it('should correctly detect the fill that is hovered over for self and next fills', function(done) {
+        var gd = createGraphDiv();
+        var mock = Lib.extendDeep({}, require('../../image/mocks/scatter_fill_self_next'));
+
+        var testPoints = [
+            [[2, 2.9], [2, 2], [1.1, 2], [5.99, 3.01], [4.6, 3.5]],
+            [[2, 3.1], [-0.2, 1.1], [5, 2.99], [7, 2], [1.2, 5.1]],
+            [[6, 5], [7, 6], [8, 5], [7, 5], [6.7, 5.3]]
+        ];
+
+        Plotly.newPlot(gd, mock).then(function() {
+            return Plotly.restyle(gd, 'hoveron', 'fills');
+        })
+        .then(function() {
+            for(var i = 0; i < testPoints.length; i++) {
+                for(var j = 0; j < testPoints[i].length; j++) {
+                    var testCoords = testPoints[i][j];
+                    var pts = _hover(gd, testCoords[0], testCoords[1], 'x', 'xy');
+                    expect(pts[i]).toBeTruthy(
+                        'correct trace not detected ' + testCoords.join(',') + ', should be ' + i
+                    );
+                    for(var k = 0; k < pts.length; k++) {
+                        var traceId = (i + 1) % pts.length;
+                        expect(pts[traceId]).toBeFalsy(
+                            'wrong trace detected ' + testCoords.join(',') + '; got ' +
+                            traceId + ' but should be ' + i
+                        );
+                    }
+                }
+            }
+        })
+        .then(done, done.fail);
+    });
+
+    it('should correctly detect the fill that is hovered over for tozeroy and tonexty fills', function(done) {
+        var gd = createGraphDiv();
+        var mock = Lib.extendDeep({}, require('../../image/mocks/scatter_fill_corner_cases'));
+
+        var traceOffset = 0;
+
+        var testPoints = [ // all the following points should be in fill region of corresponding tozeroy traces 0-4
+            [[1.5, 1.24], [1.5, 1.06]], // single point has "fill" along line to zero
+            [[0.1, 0.9], [0.1, 0.8], [1.5, 0.9], [1.5, 1.04], [2, 0.8], [2, 1.09], [3, 0.8]],
+            [[0.1, 0.75], [0.1, 0.61], [1.01, 0.501], [1.5, 0.8], [1.5, 0.55], [2, 0.74], [2, 0.55], [3, 0.74], [3, 0.51]],
+            [[0.1, 0.599], [0.1, 0.5], [0.1, 0.3], [0.99, 0.59], [1, 0.49], [1, 0.36], [1.5, 0.26], [2, 0.49], [2, 0.16], [3, 0.49], [3, 0.26]],
+            [[0.1, 0.25], [0.1, 0.1], [1, 0.34], [1.5, 0.24], [2, 0.14], [3, 0.24], [3, 0.1]],
+        ];
+
+        var outsidePoints = [ // all these should not result in a hover detection, for any trace
+            [1, 1.1], [2, 1.14],
+        ];
+
+        Plotly.newPlot(gd, mock).then(function() {
+            return Plotly.restyle(gd, 'hoveron', 'fills');
+        })
+        .then(function() {
+            var testCoords, pts;
+            var i, j, k;
+            for(i = 0; i < testPoints.length; i++) {
+                for(j = 0; j < testPoints[i].length; j++) {
+                    testCoords = testPoints[i][j];
+                    pts = _hover(gd, testCoords[0], testCoords[1], 'x', 'xy');
+                    expect(pts[traceOffset + i]).toBeTruthy(
+                        'correct trace not detected ' + testCoords.join(',') + ', should be ' + (traceOffset + i)
+                    );
+
+                    // since all polygons do extend to the zero axis, many points will be detected by the
+                    // correct trace and previous ones, but a point should not be detected as hover points
+                    // by any trace defined later than the correct trace!
+                    // (in actual hover detection, the real _hover takes care of the overlap with previous traces
+                    // so that is not an issue in practice)
+                    for(k = i + 1; k < testPoints.length; k++) {
+                        var traceId = traceOffset + k;
+                        expect(pts[traceId]).toBeFalsy(
+                            'wrong trace detected ' + testCoords.join(',') + '; got ' +
+                            traceId + ' but should be ' + (traceOffset + i)
+                        );
+                    }
+                }
+            }
+
+            for(j = 0; j < outsidePoints.length; j++) {
+                testCoords = outsidePoints[j];
+                pts = _hover(gd, testCoords[0], testCoords[1], 'x', 'xy');
+                for(k = 0; k < testPoints.length; k++) {
+                    expect(pts[i]).toBeFalsy(
+                        'trace detected for outside point ' + testCoords.join(',') + ', got ' + (traceOffset + k)
+                    );
+                }
+            }
+        })
+        .then(done, done.fail);
+    });
+
+
+    it('should correctly detect the fill that is hovered over for tonexty fills', function(done) {
+        var gd = createGraphDiv();
+        var mock = Lib.extendDeep({}, require('../../image/mocks/scatter_fill_corner_cases'));
+
+        var traceOffset = 10;
+
+        var testPoints = [ // all the following points should be in fill region of corresponding tonexty traces 10-14
+            [],
+            [[1, 1.1], [1.5, 1.24], [1.5, 1.06], [2, 1.14]],
+            [[0.1, 0.9], [0.1, 0.8], [1.5, 0.9], [1.5, 1.04], [2, 0.8], [2, 1.09], [3, 0.8]],
+            [[0.1, 0.75], [0.1, 0.61], [1.01, 0.501], [1.5, 0.8], [1.5, 0.55], [2, 0.74], [2, 0.55], [3, 0.74], [3, 0.51]],
+            [[0.1, 0.599], [0.1, 0.5], [0.1, 0.3], [0.99, 0.59], [1, 0.49], [1, 0.36], [1.5, 0.26], [2, 0.49], [2, 0.16], [3, 0.49], [3, 0.26]],
+        ];
+        var outsidePoints = [ // all these should not result in a hover detection, for any trace
+            [0.1, 0.25], [0.1, 0.1], [1, 0.34], [1.5, 0.24], [2, 0.14], [3, 0.24], [3, 0.1], [0.5, 1.15], [2.5, 1.15],
+        ];
+
+        Plotly.newPlot(gd, mock).then(function() {
+            return Plotly.restyle(gd, 'hoveron', 'fills');
+        })
+        .then(function() {
+            var testCoords, pts;
+            var i, j, k;
+            for(i = 0; i < testPoints.length; i++) {
+                for(j = 0; j < testPoints[i].length; j++) {
+                    testCoords = testPoints[i][j];
+                    pts = _hover(gd, testCoords[0], testCoords[1], 'x', 'xy2');
+                    expect(pts[traceOffset + i]).toBeTruthy(
+                        'correct trace not detected ' + testCoords.join(',') + ', should be ' + (traceOffset + i)
+                    );
+
+                    for(k = 1; k < testPoints.length; k++) {
+                        var traceId = traceOffset + ((i + k) % testPoints.length);
+                        expect(pts[traceId]).toBeFalsy(
+                            'wrong trace detected ' + testCoords.join(',') + '; got ' +
+                            traceId + ' but should be ' + (traceOffset + i)
+                        );
+                    }
+                }
+            }
+            for(j = 0; j < outsidePoints.length; j++) {
+                testCoords = outsidePoints[j];
+                pts = _hover(gd, testCoords[0], testCoords[1], 'x', 'xy2');
+                for(k = 0; k < testPoints.length; k++) {
+                    expect(pts[traceOffset + k]).toBeFalsy(
+                        'trace detected for outside point ' + testCoords.join(',') + ', got ' + (traceOffset + k)
+                    );
+                }
+            }
+        })
+        .then(done, done.fail);
+    });
+});
+
 describe('Test Scatter.style', function() {
     var gd;