How do I run a function before each test when using qUnit?

javascript, nunit, qunit, tdd

Solution

Registering a QUnit Callback

var mySetupFunc(details){/* setup code */}
QUnit.testStart(mySetupFunc);

Callback Details

As of QUnit version 1.10.0pre-A, each registered callback will receive a hash as the first (and only) parameter. I've named mine 'details' in the example above. The contents of the hash vary by callback. Here's a list of information in each hash.

begin (start of all tests)

{}  /* empty hash */

done (end of all tests)

- failed: (int) total tests failed

- passed: (int) total tests passed

- total: (int) total tests run

- runtime: (int) how long tests took to run in milliseconds

log (called within the ok() methods, etc)

- result: (boolean) true if good, false if failed

- message: (string) whatever message you passed to ok()

testStart (called at the start of each test)

- name: the name of the test (first argument passed to test() or asyncTest())

- module: the name of the module (if you haven't called the module() method, this will be undefined)

testDone (called at the end of each test)

- name: (string) the name of the test (first argument passed to test() or asyncTest())

- module: (string) the name of the module (will be undefined if you never called module())

- failed: (int) count of assertions that failed

- passed: (int) count of assertions that succeeded

- total: (int) count of all assertions in the test

moduleStart (called at the start of each module)

- module: the name of the module

moduleDone (called at the end of each test)

- module: (string) the name of the module

- failed: (int) count of assertions that failed (total for all tests in module)

- passed: (int) count of assertions that succeeded (total for all tests in module)

- total: (int) count of all assertions in the module

Examples

// There's probably a more elegant way of doing this, 
// but these two methods will add a row to a table for each test showing how long
// each test took.  
var profileStartTime = null;

function startTimer(details) {
  profileStartTime = new Date();
}

function stopTimer(details) {
  var stopDate = new Date();
  var duration = stopDate - profileStartTime;
  jQuery('#profiling').append(
    "<tr><td>" 
    + (details.module ? details.module + ":" : "") 
    + details.name 
    + "<\/td><td class='duration'>" 
    + duration 
    + "<\/td><\/tr>");
}

QUnit.testStart(startTimer);
QUnit.testDone(stopTimer);

My html table that is reference above looks like this:

<div style='margin: 10px 0;'>
  <table summary='profiling' class='profiling_table'>
    <thead>
    <tr>
      <th>Test Name</th>
      <th>Duration</th>
    </tr>
    </thead>
    <tbody id='profiling'>
    </tbody>
  </table>
</div>

Problem

Original source