auto_tests/tests/callback.js

   1 /**
   2  * @fileoverview Test cases for the callbacks.
   3  *
   4  * @author uemit.seren@gmail.com (Ümit Seren)
   5  */
   6
   7 describe("callback", function() {
   8
   9 var xhr, styleSheet;
  10
  11 beforeEach(function() {
  12   document.body.innerHTML = "<div id='graph'></div><div id='selection'></div>";
  13   xhr = XMLHttpRequest;
  14   styleSheet = document.createElement("style");
  15   styleSheet.type = "text/css";
  16   document.getElementsByTagName("head")[0].appendChild(styleSheet);
  17 });
  18
  19 afterEach(function() {
  20   window.XMLHttpRequest = xhr;
  21 });
  22
  23 var data = "X,a,b,c\n" +
  24  "10,-1,1,2\n" +
  25  "11,0,3,1\n" +
  26  "12,1,4,2\n" +
  27  "13,0,2,3\n";
  28
  29
  30 /**
  31  * This tests that when the function idxToRow_ returns the proper row and the onHiglightCallback
  32  * is properly called when the  first series is hidden (setVisibility = false)
  33  *
  34  */
  35 it('testHighlightCallbackIsCalled', function() {
  36   var h_row;
  37   var h_pts;
  38
  39   var highlightCallback = function(e, x, pts, row) {
  40     assert.equal(g, this);
  41     h_row = row;
  42     h_pts = pts;
  43   };
  44
  45   var graph = document.getElementById("graph");
  46   var g = new Dygraph(graph, data,
  47       {
  48         width: 100,
  49         height: 100,
  50         visibility: [false, true, true],
  51         highlightCallback: highlightCallback
  52       });
  53
  54   DygraphOps.dispatchMouseMove(g, 13, 10);
  55
  56   //check correct row is returned
  57   assert.equal(3, h_row);
  58   //check there are only two points (because first series is hidden)
  59   assert.equal(2, h_pts.length);
  60 });
  61
  62
  63 /**
  64  * Test that drawPointCallback isn't called when drawPoints is false
  65  */
  66 it('testDrawPointCallback_disabled', function() {
  67   var called = false;
  68
  69   var callback = function() {
  70     assert.equal(g, this);
  71     called = true;
  72   };
  73
  74   var graph = document.getElementById("graph");
  75   var g = new Dygraph(graph, data, {
  76       drawPointCallback: callback,
  77     });
  78
  79   assert.isFalse(called);
  80 });
  81
  82 /**
  83  * Test that drawPointCallback is called when drawPoints is true
  84  */
  85 it('testDrawPointCallback_enabled', function() {
  86   var called = false;
  87   var callbackThis = null;
  88
  89   var callback = function() {
  90     callbackThis = this;
  91     called = true;
  92   };
  93
  94   var graph = document.getElementById("graph");
  95   var g = new Dygraph(graph, data, {
  96       drawPoints: true,
  97       drawPointCallback: callback
  98     });
  99
 100   assert.isTrue(called);
 101   assert.equal(g, callbackThis);
 102 });
 103
 104 /**
 105  * Test that drawPointCallback is called when drawPoints is true
 106  */
 107 it('testDrawPointCallback_pointSize', function() {
 108   var pointSize = 0;
 109   var count = 0;
 110
 111   var callback = function(g, seriesName, canvasContext, cx, cy, color, pointSizeParam) {
 112     assert.equal(g, this);
 113     pointSize = pointSizeParam;
 114     count++;
 115   };
 116
 117   var graph = document.getElementById("graph");
 118   var g = new Dygraph(graph, data, {
 119       drawPoints: true,
 120       drawPointCallback: callback
 121     });
 122
 123   assert.equal(1.5, pointSize);
 124   assert.equal(12, count); // one call per data point.
 125
 126   var g = new Dygraph(graph, data, {
 127       drawPoints: true,
 128       drawPointCallback: callback,
 129       pointSize: 8
 130     });
 131
 132   assert.equal(8, pointSize);
 133 });
 134
 135 /**
 136  * Test that drawPointCallback is called for isolated points when
 137  * drawPoints is false, and also for gap points if that's enabled.
 138  */
 139 it('testDrawPointCallback_isolated', function() {
 140   var xvalues = [];
 141
 142   var g;
 143   var callback = function(g, seriesName, canvasContext, cx, cy, color, pointSizeParam) {
 144     assert.equal(g, this);
 145     var dx = g.toDataXCoord(cx);
 146     xvalues.push(dx);
 147     Dygraph.Circles.DEFAULT.apply(this, arguments);
 148   };
 149
 150   var graph = document.getElementById("graph");
 151   var testdata = [[10, 2], [11, 3], [12, NaN], [13, 2], [14, NaN], [15, 3]];
 152   var graphOpts = {
 153       labels: ['X', 'Y'],
 154       valueRange: [0, 4],
 155       drawPoints : false,
 156       drawPointCallback : callback,
 157       pointSize : 8
 158   };
 159
 160   // Test that isolated points get drawn
 161   g = new Dygraph(graph, testdata, graphOpts);
 162   assert.equal(2, xvalues.length);
 163   assert.equal(13, xvalues[0]);
 164   assert.equal(15, xvalues[1]);
 165
 166   // Test that isolated points + gap points get drawn when
 167   // drawGapEdgePoints is set.  This should add one point at the right
 168   // edge of the segment at x=11, but not at the graph edge at x=10.
 169   xvalues = []; // Reset for new test
 170   graphOpts.drawGapEdgePoints = true;
 171   g = new Dygraph(graph, testdata, graphOpts);
 172   assert.equal(3, xvalues.length);
 173   assert.equal(11, xvalues[0]);
 174   assert.equal(13, xvalues[1]);
 175   assert.equal(15, xvalues[2]);
 176 });
 177
 178 /**
 179  * This tests that when the function idxToRow_ returns the proper row and the onHiglightCallback
 180  * is properly called when the first series is hidden (setVisibility = false)
 181  *
 182  */
 183 it('testDrawHighlightPointCallbackIsCalled', function() {
 184   var called = false;
 185
 186   var drawHighlightPointCallback = function() {
 187     assert.equal(g, this);
 188     called = true;
 189   };
 190
 191   var graph = document.getElementById("graph");
 192   var g = new Dygraph(graph, data,
 193       {
 194         width: 100,
 195         height: 100,
 196         drawHighlightPointCallback: drawHighlightPointCallback
 197       });
 198
 199   assert.isFalse(called);
 200   DygraphOps.dispatchMouseMove(g, 13, 10);
 201   assert.isTrue(called);
 202 });
 203
 204 /**
 205  * Test the closest-series highlighting methods for normal and stacked modes.
 206  * Also pass in line widths for plain and highlighted lines for easier visual
 207  * confirmation that the highlighted line is drawn on top of the others.
 208  */
 209 var runClosestTest = function(isStacked, widthNormal, widthHighlighted) {
 210   var h_row;
 211   var h_pts;
 212   var h_series;
 213
 214   var graph = document.getElementById("graph");
 215   var g = new Dygraph(graph, data,
 216       {
 217         width: 600,
 218         height: 400,
 219         visibility: [false, true, true],
 220         stackedGraph: isStacked,
 221         strokeWidth: widthNormal,
 222         strokeBorderWidth: 2,
 223         highlightCircleSize: widthNormal * 2,
 224         highlightSeriesBackgroundAlpha: 0.3,
 225
 226         highlightSeriesOpts: {
 227           strokeWidth: widthHighlighted,
 228           highlightCircleSize: widthHighlighted * 2
 229         }
 230       });
 231
 232   var highlightCallback = function(e, x, pts, row, set) {
 233     assert.equal(g, this);
 234     h_row = row;
 235     h_pts = pts;
 236     h_series = set;
 237     document.getElementById('selection').innerHTML='row=' + row + ', set=' + set;
 238   };
 239
 240   g.updateOptions({highlightCallback: highlightCallback}, true);
 241
 242   if (isStacked) {
 243     DygraphOps.dispatchMouseMove(g, 11.45, 1.4);
 244     assert.equal(1, h_row);
 245     assert.equal('c', h_series);
 246
 247     //now move up in the same row
 248     DygraphOps.dispatchMouseMove(g, 11.45, 1.5);
 249     assert.equal(1, h_row);
 250     assert.equal('b', h_series);
 251
 252     //and a bit to the right
 253     DygraphOps.dispatchMouseMove(g, 11.55, 1.5);
 254     assert.equal(2, h_row);
 255     assert.equal('c', h_series);
 256   } else {
 257     DygraphOps.dispatchMouseMove(g, 11, 1.5);
 258     assert.equal(1, h_row);
 259     assert.equal('c', h_series);
 260
 261     //now move up in the same row
 262     DygraphOps.dispatchMouseMove(g, 11, 2.5);
 263     assert.equal(1, h_row);
 264     assert.equal('b', h_series);
 265   }
 266
 267   return g;
 268 };
 269
 270 /**
 271  * Test basic closest-point highlighting.
 272  */
 273 it('testClosestPointCallback', function() {
 274   runClosestTest(false, 1, 3);
 275 });
 276
 277 /**
 278  * Test setSelection() with series name
 279  */
 280 it('testSetSelection', function() {
 281   var g = runClosestTest(false, 1, 3);
 282   assert.equal(1, g.attr_('strokeWidth', 'c'));
 283   g.setSelection(false, 'c');
 284   assert.equal(3, g.attr_('strokeWidth', 'c'));
 285 });
 286
 287 /**
 288  * Test closest-point highlighting for stacked graph
 289  */
 290 it('testClosestPointStackedCallback', function() {
 291   runClosestTest(true, 1, 3);
 292 });
 293
 294 /**
 295  * Closest-point highlighting with legend CSS - border around active series.
 296  */
 297 it('testClosestPointCallbackCss1', function() {
 298   var css = "div.dygraph-legend > span { display: block; }\n" +
 299       "div.dygraph-legend > span.highlight { border: 1px solid grey; }\n";
 300   styleSheet.innerHTML = css;
 301   runClosestTest(false, 2, 4);
 302   styleSheet.innerHTML = '';
 303 });
 304
 305 /**
 306  * Closest-point highlighting with legend CSS - show only closest series.
 307  */
 308 it('testClosestPointCallbackCss2', function() {
 309   var css = "div.dygraph-legend > span { display: none; }\n" +
 310       "div.dygraph-legend > span.highlight { display: inline; }\n";
 311   styleSheet.innerHTML = css;
 312   runClosestTest(false, 10, 15);
 313   styleSheet.innerHTML = '';
 314   // TODO(klausw): verify that the highlighted line is drawn on top?
 315 });
 316
 317 /**
 318  * Closest-point highlighting with locked series.
 319  */
 320 it('testSetSelectionLocking', function() {
 321   var g = runClosestTest(false, 2, 4);
 322
 323   // Default behavior, 'b' is closest
 324   DygraphOps.dispatchMouseMove(g, 11, 4);
 325   assert.equal('b', g.getHighlightSeries());
 326
 327   // Now lock selection to 'c'
 328   g.setSelection(false, 'c', true);
 329   DygraphOps.dispatchMouseMove(g, 11, 4);
 330   assert.equal('c', g.getHighlightSeries());
 331
 332   // Unlock, should be back to 'b'
 333   g.clearSelection();
 334   DygraphOps.dispatchMouseMove(g, 11, 4);
 335   assert.equal('b', g.getHighlightSeries());
 336 });
 337
 338 /**
 339  * This tests that closest point searches work for data containing NaNs.
 340  *
 341  * It's intended to catch a regression where a NaN Y value confuses the
 342  * closest-point algorithm, treating it as closer as any previous point.
 343  */
 344 it('testNaNData', function() {
 345   var dataNaN = [
 346     [9, -1, NaN, NaN],
 347     [10, -1, 1, 2],
 348     [11, 0, 3, 1],
 349     [12, 1, 4, NaN],
 350     [13, 0, 2, 3],
 351     [14, -1, 1, 4]];
 352
 353   var h_row;
 354   var h_pts;
 355
 356   var highlightCallback = function(e, x, pts, row) {
 357     assert.equal(g, this);
 358     h_row = row;
 359     h_pts = pts;
 360   };
 361
 362   var graph = document.getElementById("graph");
 363   var g = new Dygraph(graph, dataNaN,
 364       {
 365         width: 600,
 366         height: 400,
 367         labels: ['x', 'a', 'b', 'c'],
 368         visibility: [false, true, true],
 369         highlightCallback: highlightCallback
 370       });
 371
 372   DygraphOps.dispatchMouseMove(g, 10.1, 0.9);
 373   //check correct row is returned
 374   assert.equal(1, h_row);
 375
 376   // Explicitly test closest point algorithms
 377   var dom = g.toDomCoords(10.1, 0.9);
 378   assert.equal(1, g.findClosestRow(dom[0]));
 379
 380   var res = g.findClosestPoint(dom[0], dom[1]);
 381   assert.equal(1, res.row);
 382   assert.equal('b', res.seriesName);
 383
 384   res = g.findStackedPoint(dom[0], dom[1]);
 385   assert.equal(1, res.row);
 386   assert.equal('c', res.seriesName);
 387 });
 388
 389 /**
 390  * This tests that stacked point searches work for data containing NaNs.
 391  */
 392 it('testNaNDataStack', function() {
 393   var dataNaN = [
 394     [9, -1, NaN, NaN],
 395     [10, -1, 1, 2],
 396     [11, 0, 3, 1],
 397     [12, 1, NaN, 2],
 398     [13, 0, 2, 3],
 399     [14, -1, 1, 4],
 400     [15, 0, 2, NaN],
 401     [16, 1, 1, 3],
 402     [17, 1, NaN, 3],
 403     [18, 0, 2, 5],
 404     [19, 0, 1, 4]];
 405
 406   var h_row;
 407   var h_pts;
 408
 409   var highlightCallback = function(e, x, pts, row) {
 410     assert.equal(g, this);
 411     h_row = row;
 412     h_pts = pts;
 413   };
 414
 415   var graph = document.getElementById("graph");
 416   var g = new Dygraph(graph, dataNaN,
 417       {
 418         width: 600,
 419         height: 400,
 420         labels: ['x', 'a', 'b', 'c'],
 421         visibility: [false, true, true],
 422         stackedGraph: true,
 423         highlightCallback: highlightCallback
 424       });
 425
 426   DygraphOps.dispatchMouseMove(g, 10.1, 0.9);
 427   //check correct row is returned
 428   assert.equal(1, h_row);
 429
 430   // Explicitly test stacked point algorithm.
 431   var dom = g.toDomCoords(10.1, 0.9);
 432   var res = g.findStackedPoint(dom[0], dom[1]);
 433   assert.equal(1, res.row);
 434   assert.equal('c', res.seriesName);
 435
 436   // All-NaN area at left, should get no points.
 437   dom = g.toDomCoords(9.1, 0.9);
 438   res = g.findStackedPoint(dom[0], dom[1]);
 439   assert.equal(0, res.row);
 440   assert.equal(undefined, res.seriesName);
 441
 442   // First gap, get 'c' since it's non-NaN.
 443   dom = g.toDomCoords(12.1, 0.9);
 444   res = g.findStackedPoint(dom[0], dom[1]);
 445   assert.equal(3, res.row);
 446   assert.equal('c', res.seriesName);
 447
 448   // Second gap, get 'b' since 'c' is NaN.
 449   dom = g.toDomCoords(15.1, 0.9);
 450   res = g.findStackedPoint(dom[0], dom[1]);
 451   assert.equal(6, res.row);
 452   assert.equal('b', res.seriesName);
 453
 454   // Isolated points should work, finding series b in this case.
 455   dom = g.toDomCoords(15.9, 3.1);
 456   res = g.findStackedPoint(dom[0], dom[1]);
 457   assert.equal(7, res.row);
 458   assert.equal('b', res.seriesName);
 459 });
 460
 461 it('testGapHighlight', function() {
 462   var dataGap = [
 463     [1, null, 3],
 464     [2, 2, null],
 465     [3, null, 5],
 466     [4, 4, null],
 467     [5, null, 7],
 468     [6, NaN, null],
 469     [8, 8, null],
 470     [10, 10, null]];
 471
 472   var h_row;
 473   var h_pts;
 474
 475   var highlightCallback = function(e, x, pts, row) {
 476     assert.equal(g, this);
 477     h_row = row;
 478     h_pts = pts;
 479   };
 480
 481   var graph = document.getElementById("graph");
 482   var g = new Dygraph(graph, dataGap, {
 483      width: 400,
 484      height: 300,
 485      //stackedGraph: true,
 486      connectSeparatedPoints: true,
 487      drawPoints: true,
 488      labels: ['x', 'A', 'B'],
 489      highlightCallback: highlightCallback
 490   });
 491
 492   DygraphOps.dispatchMouseMove(g, 1.1, 10);
 493   //point from series B
 494   assert.equal(0, h_row);
 495   assert.equal(1, h_pts.length);
 496   assert.equal(3, h_pts[0].yval);
 497   assert.equal('B', h_pts[0].name);
 498
 499   DygraphOps.dispatchMouseMove(g, 6.1, 10);
 500   // A is NaN at x=6
 501   assert.equal(1, h_pts.length);
 502   assert(isNaN(h_pts[0].yval));
 503   assert.equal('A', h_pts[0].name);
 504
 505   DygraphOps.dispatchMouseMove(g, 8.1, 10);
 506   //point from series A
 507   assert.equal(6, h_row);
 508   assert.equal(1, h_pts.length);
 509   assert.equal(8, h_pts[0].yval);
 510   assert.equal('A', h_pts[0].name);
 511 });
 512
 513 it('testFailedResponse', function() {
 514
 515   // Fake out the XMLHttpRequest so it doesn't do anything.
 516   XMLHttpRequest = function () {};
 517   XMLHttpRequest.prototype.open = function () {};
 518   XMLHttpRequest.prototype.send = function () {};
 519
 520   var highlightCallback = function(e, x, pts, row) {
 521     throw "should not reach here";
 522   };
 523
 524   var graph = document.getElementById("graph");
 525   graph.style.border = "2px solid black";
 526   var g = new Dygraph(graph, "data.csv", { // fake name
 527      width: 400,
 528      height: 300,
 529      highlightCallback : highlightCallback
 530   });
 531
 532   DygraphOps.dispatchMouseOver_Point(g, 800, 800);
 533   DygraphOps.dispatchMouseMove_Point(g, 100, 100);
 534   DygraphOps.dispatchMouseMove_Point(g, 800, 800);
 535
 536   var oldOnerror = window.onerror;
 537   var failed = false;
 538   window.onerror = function() { failed = true; return false; }
 539
 540   DygraphOps.dispatchMouseOut_Point(g, 800, 800); // This call should not throw an exception.
 541
 542   assert.isFalse(failed, "exception thrown during mouseout");
 543 });
 544
 545
 546 // Regression test for http://code.google.com/p/dygraphs/issues/detail?id=355
 547 it('testHighlightCallbackRow', function() {
 548   var highlightRow;
 549   var highlightCallback = function(e, x, pts, row) {
 550     assert.equal(g, this);
 551     highlightRow = row;
 552   };
 553
 554   var graph = document.getElementById("graph");
 555   var g = new Dygraph(graph,
 556     "X,Y,Z\n" +
 557     "0,1,2\n" +  // 0
 558     "1,2,3\n" +  // 100
 559     "2,3,4\n" +  // 200
 560     "3,4,5\n" +  // 300
 561     "4,5,6\n",   // 400
 562     { // fake name
 563        width: 400,
 564        height: 300,
 565        highlightCallback : highlightCallback
 566     });
 567
 568   // Mouse over each of the points
 569   DygraphOps.dispatchMouseOver_Point(g, 0, 0);
 570   DygraphOps.dispatchMouseMove_Point(g, 0, 0);
 571   assert.equal(0, highlightRow);
 572   DygraphOps.dispatchMouseMove_Point(g, 100, 0);
 573   assert.equal(1, highlightRow);
 574   DygraphOps.dispatchMouseMove_Point(g, 200, 0);
 575   assert.equal(2, highlightRow);
 576   DygraphOps.dispatchMouseMove_Point(g, 300, 0);
 577   assert.equal(3, highlightRow);
 578   DygraphOps.dispatchMouseMove_Point(g, 400, 0);
 579   assert.equal(4, highlightRow);
 580
 581   // Now zoom and verify that the row numbers still refer to rows in the data
 582   // array.
 583   g.updateOptions({dateWindow: [2, 4]});
 584   DygraphOps.dispatchMouseOver_Point(g, 0, 0);
 585   DygraphOps.dispatchMouseMove_Point(g, 0, 0);
 586   assert.equal(2, highlightRow);
 587   assert.equal('2: Y: 3 Z: 4', Util.getLegend());
 588 });
 589
 590 /**
 591  * Test that underlay callback is called even when there are no series,
 592  * and that the y axis ranges are not NaN.
 593  */
 594 it('testUnderlayCallback_noSeries', function() {
 595   var called = false;
 596   var yMin, yMax;
 597
 598   var callback = function(canvas, area, g) {
 599     assert.equal(g, this);
 600     called = true;
 601     yMin = g.yAxisRange(0)[0];
 602     yMax = g.yAxisRange(0)[1];
 603   };
 604
 605   var graph = document.getElementById("graph");
 606   var g = new Dygraph(graph, "\n", {
 607       underlayCallback: callback
 608     });
 609
 610   assert.isTrue(called);
 611   assert.isFalse(isNaN(yMin));
 612   assert.isFalse(isNaN(yMax));
 613 });
 614
 615 /**
 616  * Test that underlay callback receives the correct y-axis range.
 617  */
 618 it('testUnderlayCallback_yAxisRange', function() {
 619   var called = false;
 620   var yMin, yMax;
 621
 622   var callback = function(canvas, area, g) {
 623     assert.equal(g, this);
 624     yMin = g.yAxisRange(0)[0];
 625     yMax = g.yAxisRange(0)[1];
 626   };
 627
 628   var graph = document.getElementById("graph");
 629   var g = new Dygraph(graph, "\n", {
 630       valueRange: [0,10],
 631       underlayCallback: callback
 632     });
 633
 634   assert.equal(0, yMin);
 635   assert.equal(10, yMax);
 636 });
 637
 638 /**
 639  * Test that drawPointCallback is called for isolated points and correct idx for the point is returned.
 640  */
 641 it('testDrawPointCallback_idx', function() {
 642   var indices = [];
 643
 644   var g;
 645   var callback = function(g, seriesName, canvasContext, cx, cy, color, pointSizeParam,idx) {
 646     assert.equal(g, this);
 647     indices.push(idx);
 648     Dygraph.Circles.DEFAULT.apply(this, arguments);
 649   };
 650
 651   var graph = document.getElementById("graph");
 652
 653   var testdata = [[10, 2], [11, 3], [12, NaN], [13, 2], [14, NaN], [15, 3]];
 654   var graphOpts = {
 655       labels: ['X', 'Y'],
 656       valueRange: [0, 4],
 657       drawPoints : false,
 658       drawPointCallback : callback,
 659       pointSize : 8
 660   };
 661
 662   // Test that correct idx for isolated points are passed to the callback.
 663   g = new Dygraph(graph, testdata, graphOpts);
 664   assert.equal(2, indices.length);
 665   assert.deepEqual([3, 5],indices);
 666
 667   // Test that correct indices for isolated points + gap points are passed to the callback when
 668   // drawGapEdgePoints is set.  This should add one point at the right
 669   // edge of the segment at x=11, but not at the graph edge at x=10.
 670   indices = []; // Reset for new test
 671   graphOpts.drawGapEdgePoints = true;
 672   g = new Dygraph(graph, testdata, graphOpts);
 673   assert.equal(3, indices.length);
 674   assert.deepEqual([1, 3, 5],indices);
 675
 676
 677   //Test that correct indices are passed to the callback when zoomed in.
 678   indices = []; // Reset for new test
 679   graphOpts.dateWindow = [12.5,13.5]
 680   graphOpts.drawPoints = true;
 681   testdata = [[10, 2], [11, 3], [12, 4], [13, 2], [14, 5], [15, 3]];
 682   g = new Dygraph(graph, testdata, graphOpts);
 683   assert.equal(3, indices.length);
 684   assert.deepEqual([2, 3, 4],indices);
 685 });
 686
 687 /**
 688  * Test that the correct idx is returned for the point in the onHiglightCallback.
 689   */
 690 it('testDrawHighlightPointCallback_idx', function() {
 691   var idxToCheck = null;
 692
 693   var drawHighlightPointCallback = function(g, seriesName, canvasContext, cx, cy, color, pointSizeParam,idx) {
 694     assert.equal(g, this);
 695     idxToCheck = idx;
 696   };
 697   var testdata = [[1, 2], [2, 3], [3, NaN], [4, 2], [5, NaN], [6, 3]];
 698   var graph = document.getElementById("graph");
 699   var g = new Dygraph(graph, testdata, {
 700         drawHighlightPointCallback: drawHighlightPointCallback,
 701         labels: ['X', 'Y']
 702       });
 703
 704   assert.isNull(idxToCheck);
 705   DygraphOps.dispatchMouseMove(g, 3, 0);
 706   // check that NaN point is not highlighted
 707   assert.isNull(idxToCheck);
 708   DygraphOps.dispatchMouseMove(g, 1, 2);
 709   // check that correct index is returned
 710   assert.equal(0,idxToCheck);
 711   DygraphOps.dispatchMouseMove(g, 6, 3);
 712   assert.equal(5,idxToCheck);
 713 });
 714
 715 });