title: Good literature on unit testing?
body: <p>Where can I find good literature on unit testing?  Book titles and links are welcome.</p>
  
  <p>Update: 
  Here is a list of books mentioned in answers below</p>
  
  <p><a href="https://rads.stackoverflow.com/amzn/click/0131495054" rel="nofollow noreferrer">xUnit Test Patterns: Refactoring Test Code</a></p>
  
  <p><a href="http://www.growing-object-oriented-software.com/" rel="nofollow noreferrer">Growing Object-Oriented Software Guided by Tests</a></p>
  
  <p><a href="http://www.artofunittesting.com/" rel="nofollow noreferrer">The Art Of Unit Testing</a></p>
  
  <p>The real challenge of software testing is solving the puzzle of test design.</p>
  
  <p>Testing Object-Oriented Systems: Models, Patterns, and Tools provides three dozen test design patterns applicable to unit test design. It also provides many design patterns for test automation. These patterns distill many hard-won best practices and research insights.</p>
  
  <p><a href="https://pragprog.com/titles/utj/pragmatic-unit-testing-in-java-with-junit" rel="nofollow noreferrer">Pragmatic Unit Testing</a></p>
  
  <p><a href="https://rads.stackoverflow.com/amzn/click/0321146530" rel="nofollow noreferrer">Test Driven Development: By Example</a></p>