add 'attr' key to box/hover pointData

- this makes all box/hover labels render even when their x/y
  positions overlap perfectly.

Author: etpinard

src/traces/box/hover.js

@@ -171,6 +171,7 @@ function hoverOnBoxes(pointData, xval, yval, hovermode) {
         var valPx = vAxis.c2p(val, true);
         var pointData2 = Lib.extendFlat({}, pointData);
 
+        pointData2.attr = attr;
         pointData2[vLetter + '0'] = pointData2[vLetter + '1'] = valPx;
         pointData2[vLetter + 'LabelVal'] = val;
         pointData2[vLetter + 'Label'] = (t.labels ? t.labels[attr] + ' ' : '') + Axes.hoverLabelText(vAxis, val);

test/jasmine/tests/box_test.js

@@ -438,23 +438,21 @@ describe('Test box hover:', function() {
         nums: '0.6',
         name: 'pt #0'
     }, {
-        desc: 'when zoomed in, cropping out labels',
+        desc: 'when zoomed in, within q1-q3 making min/q1 and max/q3 overlap',
         mock: {
             data: [{
                 type: 'box',
                 y: [1, 2, 2, 3]
             }],
             layout: {
-                // cropping out q1 and max w/o failing during hoverAvoidOverlap
-                // https://github.com/plotly/plotly.js/issues/3962
                 yaxis: {range: [1.6, 2.4]},
                 width: 400,
                 height: 400
             }
         },
         pos: [200, 200],
-        nums: ['median: 2', 'q1: 1.5', 'q3: 2.5'],
-        name: ['', '', ''],
+        nums: ['median: 2', 'q1: 1.5', 'q3: 2.5', 'max: 3', 'min: 1'],
+        name: ['', '', '', '', ''],
         axis: 'trace 0'
     }].forEach(function(specs) {
         it('should generate correct hover labels ' + specs.desc, function(done) {

test/jasmine/tests/violin_test.js

@@ -745,7 +745,7 @@ describe('Test violin hover:', function() {
 
             actual = actual.sort(function(a, b) { return a[1].top - b[1].top; });
 
-            expect(actual.length).toBe(7, '# of value hover labels');
+            expect(actual.length).toBe(8, '# of value hover labels');
 
             for(var i = 0; i < actual.length - 1; i++) {
                 var a = actual[i];