Mastering JavaScript

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Chapter 6 Martin Fowler advocates the test pyramid (http://martinfowler. com/bliki/TestPyramid.html) strategy to make sure that we have a high number of unit tests to ensure maximum code coverage. The test pyramid says that you should write many more low-level unit tests than higher level integration and UI tests. There are two important testing strategies that we will discuss in this chapter. Test-driven development Test-driven development (TDD) has gained a lot of prominence in the last few years. The concept was first proposed as part of the Extreme Programming methodology. The idea is to have short repetitive development cycles where the focus is on writing the test cases first. The cycle looks as follows: 1. Add a test case as per the specifications for a specific unit of code. 2. Run the existing suite of test cases to see if the new test case that you wrote fails—it should (because there is no code for this unit yet). This step ensures that the current test harness works well. 3. Write the code that serves mainly to confirm the test case. This code is not optimized or refactored or even entirely correct. However, this is fine at the moment. 4. Rerun the tests and see if all the test cases pass. After this step, you will be confident that the new code is not breaking anything. 5. Refactor the code to make sure that you are optimizing the unit and handling all corner cases. These steps are repeated for all the new code that you add. This is an elegant strategy that works really well for the agile methodology. TDD will be successful only if the testable units of code are small and confirm only to the test case and nothing more. It is important to write small, modular, and precise code units that have input and output confirming the test case. Behavior-driven development A very common problem while trying to follow TDD is vocabulary and the definition of correctness. BDD tries to introduce a ubiquitous language while writing the test cases when you are following TDD. This language makes sure that both the business and engineering teams are talking about the same thing. [ 147 ] www.it-ebooks.info
Testing and Debugging We will use Jasmine as the primary BDD framework and explore various testing strategies. You can install Jasmine by downloading the standalone package from https://github.com/jasmine/jasmine/releases/download/ v2.3.4/jasmine-standalone-2.3.4.zip. When you unzip this package, you will have the following directory structure: The lib directory contains the <strong>JavaScript</strong> files that you need in your project to start writing Jasmine test cases. If you open SpecRunner.html, you will find the following <strong>JavaScript</strong> files included in it: [ 148 ] www.it-ebooks.info
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Mastering JavaScript Copyright © 2
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About the Author Ved Antani is an A
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www.PacktPub.com Support files, eBo
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Table of Contents The eval() method
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Table of Contents Runtime exception
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Preface What this book covers Chapt
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Preface When we wish to draw your a
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Piracy Piracy of copyrighted materi
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JavaScript Primer While JavaScript
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JavaScript Primer You can save this
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JavaScript Primer Hello World No pr
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JavaScript Primer JavaScript suppor
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JavaScript Primer The second line i
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JavaScript Primer One important thi
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JavaScript Primer • Use the Boole
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JavaScript Primer Here are some exa
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JavaScript Primer This is fine beca
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JavaScript Primer • Logical NOT:
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JavaScript Primer One way is to put
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JavaScript Primer In this example,
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JavaScript Primer Strict equality i
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JavaScript Primer However, there ar
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JavaScript Primer What about arrays
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JavaScript Primer JavaScript style
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JavaScript Primer //Set off operato
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JavaScript Primer The following exa
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JavaScript Primer Naming Naming is
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JavaScript Primer You switch on the
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JavaScript Primer Once JSHint is in
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Functions, Closures, and Modules As
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Functions, Closures, and Modules On
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Functions, Closures, and Modules va
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Page 141 and 142: JavaScript Patterns Design patterns
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Server-Side JavaScript An asynchron
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Server-Side JavaScript Consider the
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Server-Side JavaScript If you want
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Server-Side JavaScript When you exe
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Server-Side JavaScript This fragmen
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Server-Side JavaScript var _server
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Server-Side JavaScript The geo modu
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Server-Side JavaScript Installing p
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Server-Side JavaScript There is a c
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Server-Side JavaScript The recorded
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Server-Side JavaScript Summary In t
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closures 66-70 command line interfa
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match from class of characters 77,
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W waterfall graph 220 weak equality
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HTML5 Boilerplate Web Development I
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