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The open standards JavaScript and HTML weren´t originally intended for the development of complex applications but to render the contents of hyperlinked text documents known as the websites in the Internet. Professional development of applications running in the browser is still in its early days which often manifests itself in the ignorance of established engineering practices and techniques for quality assurance of software projects. One explanation for this ignorance could be that the necessary tools to support these practices had to be re-developed from the ground up to fit the browser environment and that most of them are still very new and relatively unknown. One of these established practices of agile software engineering is Test-Driven-Development which can be used to produce high quality software with less defects and exhaustive test coverage. This book examines the importance of Test-Driven-Development in the context of web development and describes the problems that can arise if no countermeasures are taken. It proposes the use of Test Doubles as potential improvement of Test-Driven-Development by replacing dependencies with undesirable side effects of components under test. Multiple practical examples are used to measure and discuss the effect of Test Doubles on Test-Driven-Development.

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Software engineer from Austria who studied Computer Science at the University of Applied Sciences, Salzburg with the focus in Web & Communities. Throughout his career as front-end Javascript developer he gained a lot of practical experience in testing complex web applications and writing efficient test suites.

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