Function _assert

test/jasmine/tests/box_test.js:1121–1126

(msg, exp)

        }

        function _assert(msg, exp) {
            var trace3 = d3Select(gd).select('.boxlayer > .trace');
            _assertOne(msg, exp, trace3, 'boxCnt', 'path.box');
            _assertOne(msg, exp, trace3, 'meanlineCnt', 'path.mean');
            _assertOne(msg, exp, trace3, 'ptsCnt', 'path.point');
        }

        Plotly.newPlot(gd, fig)
        .then(function() {