title: Make tests run in specific order
body: <p>Is there a way to override the order in which <code>testthat</code> tests run when using <code>Ctrl + Shift + T</code> in RStudio?</p>
  
  <p>It appears that they are presently running in alphabetical order, so I suppose I could change the name of the files (numbered). But is there a more generic way to set the order?</p>
  
  <p>My testthat.R file looks like: </p>
  
  <pre><code>library(testthat)
  test_check("myPackage")
  </code></pre>
  
  <p>The reason that I ask is that some of my code has an obvious heirarchy (class creation, then methods, then other things built on top) and there are so many tests that identifying the "first" failure will simplify things significantly. </p>