Testing Firefox changes

The next step after customizing Firefox to open new tabs adjacent to the current tab, was to create an automated test to validate that everything works in all situations.

The first step is to (re)build with the enable-tests option  by placing "ac_add_options --enable-tests" in .mozconfig

Now we'll need to write our test() function using assertions; ok(), is(), isnot()

ok(val, "val exists!");                        // Tests existence
is(val1, val2, "val1 equals val2");            // Tests equality
isnot(val1, val2, "val1 does not equal val2"); // Tests if not equal

My test script looks like this:

function test() {
 var firstTab = gBrowser.addTab();

 var tabs = gBrowser.tabs;

 is(tabs.length, 2, "2 tabs are open");
 is(gBrowser.selectedTab._tPos, 0, "First tab is selected");

 var newTab = gBrowser.addTab();

 is(gBrowser.selectedTab._tPos, 0, "first tab selected");
 is(tabs[2]._tPos, newTab._tPos, "Was inserted at #3");

 gBrowser.moveTabTo(newTab,0);
 is(newTab._tPos,0, "moved new tab to first position");
 var tempLen = tabs.length;
 gBrowser.removeTab(newTab);
 is(tabs.length, tempLen-1 ,"deleted newTab");

 while (tabs.length > 1)
  gBrowser.removeCurrentTab();
}

So where do we put this file?
src\obj-i686-pc-mingw32\_tests\testing\mochitest\browser\browser\base\content\test\browser_tab_test.js

To run the test script run navigate to the src directory and run:

 TEST_PATH=browser/base/content/test/YOUR_TEST_SCRIPT.js make -C $(OBJDIR) mochitest-browser-chrome

When the test finishes you should see the results as either TEST-PASS or TEST-UNEXPECTED-FAIL.