Regression and unit tests

From LimeSurvey Manual

Warning : Every time you discover a new bug, you should add a regression test to make sure it does not appear again.
Warning : NEVER run tests on a productive system. The tests WILL modify the database.
Hint: Always make sure new code follows the PSR-2 standard for PHP. Use codesniffer and mess detector to catch common bugs and style fixes in your code.

Since LimeSurvey 2.65.6 you have the possibility to add unit tests to LimeSurvey.


In an ideal world, a regression test is added every time a new bug is discovered. That way you make sure you never have to fix the same bug twice.

To enable unit testing, you have to issue the command

$ touch enabletests

in the LimeSurvey root folder.

The test system uses phpunit, which you need to install first.

After you've done that, you should be able to write

$ phpunit

in the root folder to run the tests. This is an example of the output:

 $ phpunit
 PHPUnit 5.6.2 by Sebastian Bergmann and contributors.

 ....                                                                4 / 4 (100%)

Time: 713 ms, Memory: 14.00MB

OK (4 tests, 24 assertions)

You can get some more information if you use the switch --testdox:

$ phpunit --testdox
PHPUnit 5.6.2 by Sebastian Bergmann and contributors.

 [x] Q 1

 [x] Wrong input
 [x] Correct date format
 [x] Q 1

Feel free to browse the test in the repository.

What can be tested?

Right now, there are tests for the expression manager, qanda and updatedb helper. You cannot test Javascript yet, but it can be added.

What should be tested?

Everything that can be reported as a bug should be tested, but especially critical is of course the relation between user input and database, that is, that the correct answer is saved.

Adding a test

First of all, make sure to head over to the phpunit web site and read the introduction.

When done with that, I will assume you want to add a new test for a question type. Tests for questions are stored in folder tests/questions.

You should create a minimal survey to reproduce your bug. Export it as an lss file and put it in tests/data/surveys. Then create a class for your test. Name the file the same as the class, like "DateTimeForwardBackTest.php". The class name must end with "Test", so phpunit can find it.

Inside the class you might want to add code to import and delete the survey. I usually do this class-wide, which means that the survey gets imported when the class is loaded and then deleted when all tests in the class is done (whether failed or successfully).

The static methods setupBeforeClass and teardownAfterClass is used to setup and teardown the test fixture, respectively. You can read more about fixtures in the phpunit manual.

Let's list what we know so far:

namespace ls\tests;

use PHPUnit\Framework\TestCase;

 * @since 2017-06-16
 * @author Olle Haerstedt 
class DateTimeDefaultAnswerExpressionTest extends \PHPUnit_Framework_TestCase
  public static function setupBeforeClass()
    // Init stuff

  public static function teardownAfterClass()
    // Tear down what you setup before.