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

• An automated, distributed software testing infrastructure, for conducting
performance analyses of Ajax web applications. The proposed infrastructure
is implemented in an open source framework called Chiron.
Chiron can simulate thousands of concurrent web users and collect
data on network usage, server performance, and data coherence. We
have used Chiron to conduct an empirical study for a comparison of the
performance tradeoffs of using push- (Comet) and pull-based web data
delivery techniques on Ajax applications. The results of our empirical
study help engineers to anticipate the effects of key parameters such as
pull and push intervals, and the number of web clients on, for instance,
data coherence and server performance.
• A crawling method for Ajax, based on dynamic analysis of single-page
web interfaces. The method infers a state-flow graph of the navigational
paths by running the web application in an embedded browser, detecting
and executing clickable elements, and analyzing the user interface
state changes. The technique is implemented in an open source tool
called Crawljax, which can automatically make a full pass over Ajax
web interfaces.
• An automated technique for testing Ajax user interfaces. The technique
is based on an extension of the crawling technique to dynamically find
the doorways to different states and data entry points on Ajax web interfaces.
We propose to use invariants, as oracle, on the DOM tree and the
inferred state machine to detect faults. The technique is implemented in
an open source tool called Atusa, offering a plugin-mechanism to add
invariant checking components and application-specific state validators.
Atusa provides a number of generic invariant plugins, such as DOM
validation and test suite generation.
7.2 Research Questions Revisited
In the beginning of this thesis, we formulated a set of research questions.
We believe that the contributions indicate that we have successfully met the
objectives. We will now discuss the results for each chapter individually and
with respect to other chapters.
Research Question 1
What are the fundamental architectural differences and tradeoffs between designing
a classical and an Ajax-based web application? Can current architectural
styles describe Ajax? If not, can we propose an architectural style taylored for
Ajax?
In order to answer the first research question, Chapter 2 based its foundation
on the software architecture literature, to understand the key properties
of a new, complex, and dynamic software family. Software architecture turned
154 7.2. Research Questions Revisited