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Refactoring Unit Tests

Refactoring Unit Tests

Anyone who wants to change existing code must also understand the associated tests. This brief presentation shows how comprehensible JUnit tests can look like: Existing unit tests are refactored using descriptive names, BDD structures and speaking assertions. JUnit 4, AssertJ and Awaitility are used.

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Alexander Schwartz

December 07, 2017
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  1. .consulting .solutions .partnership Refactoring Unit Tests Alexander Schwartz, Principal IT

    Consultant JUG Darmstadt / 7. December 2017
  2. Demo © msg | Dezember 2017 | Refactoring Unit Tests

    | Alexander Schwartz 2
  3. Summary © msg | Dezember 2017 | Refactoring Unit Tests

    | Alexander Schwartz 3 Ideas: • Consider tests to check for features, not (only) classes • Introduce test methods with “should” to describe expected behavior • Add a “when” to describe conditions for a test • Use underscores to make the methods readable. Use capital letters and even Umlauts! • Break down the test in given/when/then • Try out AssertJ matchers for readability and fluent API • Use Awaitility for fast execution and avoid fixed sleep in execution Benefits: • When a test fails you can read up about the requirements in the code • Tests can be linked to business requirements and/or acceptance criteria • Test scope (what to test) and test steps (how to test) can be discussed with business owners
  4. Links © msg | Dezember 2017 | Refactoring Unit Tests

    | Alexander Schwartz 4 JUnit http://junit.org AssertJ http://joel-costigliola.github.io/assertj/ Awaitility https://github.com/awaitility/awaitility Samples of today’s demo https://github.com/ahus1/bdd-examples @ahus1de Other libraries (not shown today) JGiven http://jgiven.org/ JUnit Dataprovider https://github.com/TNG/junit-dataprovider Mockito http://site.mockito.org/
  5. .consulting .solutions .partnership Alexander Schwartz Principal IT Consultant +49 171

    5625767 alexander.schwartz@msg-systems.com @ahus1de msg systems ag (Headquarters) Robert-Buerkle-Str. 1, 85737 Ismaning Germany www.msg-systems.com