Make sure you are signed in. You will not see a Test Tab if you are working on a local form.
I am guessing that you are using FormsCentral for Acrobat (the desktop app that comes with Acrobat Pro XI).
(1) make sure you are signed-in (see top right corner)
(2) make sure your local form is moved online
Not that you won't see a Test Tab for imported PDF forms. To test export the PDF and test the form in Acrobat.