1 files changed, 56 insertions, 0 deletions
diff --git a/browser/base/content/test/newtab/browser_newtab_bug752841.js b/browser/base/content/test/newtab/browser_newtab_bug752841.js
new file mode 100644
index 000000000..e3faad13f
--- /dev/null
+++ b/browser/base/content/test/newtab/browser_newtab_bug752841.js
@@ -0,0 +1,56 @@
+/* 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 getCellsCount()
+{
+  return ContentTask.spawn(gBrowser.selectedBrowser, {}, function* () {
+    return content.gGrid.cells.length;
+  });
+}
+
+add_task(function* () {
+  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 (15 is the default value -> 5 x 3)
+  let previousValues = [15, 1, 1, 1, 1, 8];
+
+  yield* addNewTabPageTab();
+  let existingTab = gBrowser.selectedTab;
+
+  for (let i = 0; i < expectedValues.length; i++) {
+    let existingTabGridLength = yield getCellsCount();
+    is(existingTabGridLength, previousValues[i],
+      "Grid length of existing page before update is correctly.");
+
+    yield pushPrefs([PREF_NEWTAB_ROWS, testValues[i].row]);
+    yield pushPrefs([PREF_NEWTAB_COLUMNS, testValues[i].column]);
+
+    existingTabGridLength = yield getCellsCount();
+    is(existingTabGridLength, expectedValues[i],
+      "Existing page grid is updated correctly.");
+
+    yield* addNewTabPageTab();
+    let newTab = gBrowser.selectedTab;
+    let newTabGridLength = yield getCellsCount();
+    is(newTabGridLength, expectedValues[i],
+      "New page grid is updated correctly.");
+
+    yield BrowserTestUtils.removeTab(newTab);
+  }
+
+  gBrowser.removeTab(existingTab);
+});
+