Abstract:

In the course “Web Technologies” (degree program “Industrial Engineering Media” the University of Applied Sciences in Stuttgart, Germany), automatic tests for checking the correctness of student assignments were introduced this year.

In the module, the participants get to know two technologies, HTML and CSS. The students should develop the competence to create simple websites based on their own ideas. The focus of the course is on the correct and precise application of the two technologies. The course is very practical: there are a theoretical introduction to each subject area and many small exercises that students should work on autonomously. During the course, the supervisor's task is to support the students who are unable to progress with the task solution and to check that the solutions are correct.

The correctness of the solutions results from three independent aspects:
1. The implementation in HTML must be correct.
2. The implementation in CSS must be correct.
3. The solution must fit the task, so it must also be correct in terms of content.

To test the correctness of a solution, automated tests have been offered since the beginning of this year, which check all three aspects described above.

The following scenario describes how such a check is carried out: The students develop their solutions in their own development environments on the local computer. A link to the associated tests for this task will be provided in each task text, which will take the students to a special web page. There, they can upload their solutions, which are then checked automatically and the result is shown to the students directly under their solutions. The test can be repeated several times. The aim is for the students to remedy all displayed errors autonomously. They can recognize a correct solution by the fact that the automatic tests no longer deliver any error messages.

In this paper, the experiences of using the automatic tests during the course will be presented. The main questions to be answered are:
1. Do the automatic tests actually relieve the supervisor at courses with many participants so that he can take care of the students who cannot get on without his help?
2. Can the tests be designed intuitively enough so that students can use them autonomously?
3. Can the error messages be formulated meaningfully enough so that the students can see where the cause of their errors could be?
4. In the case of error messages, can students autonomously find and correct the actual cause of the error on the basis of the information provided?
5. Can such tests be formulated flexibly enough so that solutions that do not correspond 100% to the task are also accepted? Example: the task is to color the background of a website blue. From a technical point of view, a solution is also correct in which the background color is set to red, since it is about changing the background color in principle and not about choosing a specific color. This flexibility must be taken into account in an automatic test.

Keywords:

Web technologies, automatic tests, HTML, CSS.