What does enable_testing() do in cmake? : <p>I see that to add my google tests(for my cpp project), I need to make a call to enable_testing() in the root source directory. Can someone explain what this really does? Also why would cmake not make this default?</p>

<p>This is all I could get from the documentation.</p>

<blockquote>
  <p>Enables testing for this directory and below. See also the add_test()
  command. Note that ctest expects to find a test file in the build
  directory root. Therefore, this command should be in the source
  directory root.</p>
</blockquote>
