title: conditionally running tests with build flags not working
body: <p>I'm running some tests in golang and I want to avoid running the slow ones, for example this one uses bcrypt so it's slow:</p>
  
  <pre><code>// +build slow
  package services
  
  import (
      "testing"
      "testing/quick"
  )
  
  // using bcrypt takes too much time, reduce the number of iterations.
  var config = &amp;quick.Config{MaxCount: 20}
  
  func TestSignaturesAreSame(t *testing.T) {
      same := func(simple string) bool {
          result, err := Encrypt(simple)
          success := err == nil &amp;&amp; ComparePassWithHash(simple, result)
          return success
      }
  
      if err := quick.Check(same, config); err != nil {
          t.Error(err)
      }
  }
  </code></pre>
  
  <p>To avoid running this in every iteration I've set up the <code>// +build slow</code> flag. This should only run when doing <code>go test -tags slow</code> but unfortunately it's running every time (the -v flag shows it's running).</p>
  
  <p>Any idea what's wrong?</p>