The Tor Browser / file revision

 /* Any copyright is dedicated to the Public Domain.

    http://creativecommons.org/publicdomain/zero/1.0/ */

 const PREF_NEWTAB_ROWS = "browser.newtabpage.rows";

 const PREF_NEWTAB_COLUMNS = "browser.newtabpage.columns";

 function runTests() {

   let testValues = [

     {row: 0, column: 0},

     {row: -1, column: -1},

     {row: -1, column: 0},

     {row: 0, column: -1},

     {row: 2, column: 4},

     {row: 2, column: 5},

   ];

   // Expected length of grid

   let expectedValues = [1, 1, 1, 1, 8, 10];

    // Values before setting new pref values (9 is the default value -> 3 x 3)

   let previousValues = [9, 1, 1, 1, 1, 8];

   let existingTab, existingTabGridLength, newTab, newTabGridLength;

   yield addNewTabPageTab();

   existingTab = gBrowser.selectedTab;

   for (let i = 0; i < expectedValues.length; i++) {

     gBrowser.selectedTab = existingTab;

     existingTabGridLength = getGrid().cells.length;

     is(existingTabGridLength, previousValues[i],

       "Grid length of existing page before update is correctly.");

     Services.prefs.setIntPref(PREF_NEWTAB_ROWS, testValues[i].row);

     Services.prefs.setIntPref(PREF_NEWTAB_COLUMNS, testValues[i].column);

     existingTabGridLength = getGrid().cells.length;

     is(existingTabGridLength, expectedValues[i],

       "Existing page grid is updated correctly.");

     yield addNewTabPageTab();

     newTab = gBrowser.selectedTab;

     newTabGridLength = getGrid().cells.length;

     is(newTabGridLength, expectedValues[i],

       "New page grid is updated correctly.");

     gBrowser.removeTab(newTab);

   }

   gBrowser.removeTab(existingTab);

   Services.prefs.clearUserPref(PREF_NEWTAB_ROWS);

   Services.prefs.clearUserPref(PREF_NEWTAB_COLUMNS);

 }