title: iOS Unit Testing: XCTestSuite, XCTest, XCTestRun, XCTestCase methods
body: <p>In my daily unit test coding with Xcode, I only use XCTestCase. There are also these other classes that don't seem to get used much such as: XCTestSuite, XCTest, XCTestRun.</p>
  
  <p>What are XCTestSuite, XCTest, XCTestRun for? When do you use them?</p>
  
  <p>Also, XCTestCase header has a few methods such as:</p>
  
  <pre><code>defaultTestSuite
  invokeTest
  testCaseWithInvocation:
  testCaseWithSelector:
  </code></pre>
  
  <p>How and when to use the above?</p>
  
  <p>I am having trouble finding documentation on the above XCTest-classes and methods.</p>