Analysis and Testing of Ajax-based Single-page Web Applications

correct behavior. Violations in the invariants can be seen as candidate faults.
The invariants can be generic, such as DOM validation and correctness, or
application-specific, constraining DOM elements’ properties, relations, and
occurrences.
The proposed technique in Chapter 6 provides evidence that automatic testing
of dynamic interfaces is possible through invariants. Invariants not only
help during the test process to automate the oracle, but at the same time they
can form an appropriate vehicle for documenting the system behavior, especially
in web-based applications where documenting the dynamic behavior is
far from trivial.
As a comparison, Chiron, presented in Chapter 4, analyzes the behavior
of the web application by simulating a high number of clients and examining
system properties such as server performance, network usage, data coherence,
etc. On the other hand, Atusa focuses on testing the run-time behavior of one
single web application, by simulating user events on the client interface and
analyzing the response.
Atusa does not replace manual user interface testing, but augments it. One
limitation of our approach is the state space explosion, which is an inherent
problem in all state-based testing approaches and our tool is not an exception,
although we do provide a number of mechanisms to constrain the state space,
as discussed in Chapter 6.
7.3 Evaluation
In this section we discus our research challenges and the threats to validity of
our results.
The work described in this thesis started under the Single Page Computer
Interaction (SPCI) project, a project initiated by:
• Backbase, a computer software company specialized in creating Ajaxbased
web applications, founded in 2003 in Amsterdam, see 2.2.3 for
more details about their Ajax framework.
• CWI, the Dutch National Research Institute for Mathematics and Computer
Science, and
• the Delft University of Technology.
In fact, the term Ajax was not even coined yet when the project’s proposal
was written. The goal of the project was to better understand the implications
of adopting modern standards-based single-page web applications.
One challenge we faced at the start of the project was that the literature
on modern web applications in general and Ajax in particular, appeared to
be a scarcely populated area. Many traditional software and web engineering
techniques appeared to be unfit for Ajax and therefore had to be adapted to
the new requirements.
Chapter 7. Conclusion 159