Check for tornado before running frontend.html tests.

IPython/testing/iptest.py

@@ -111,6 +111,7 b" if os.name == 'nt':"
 else:
     have['zmq'] = test_for('zmq', '2.1.4')
 have['qt'] = test_for('IPython.external.qt')
+have['tornado'] = test_for('tornado')
 
 #-----------------------------------------------------------------------------
 # Functions and classes
@@ -205,6 +206,9 b' def make_exclude():'
         exclusions.extend([ipjoin('lib', 'pylabtools'),
                            ipjoin('lib', 'tests', 'test_pylabtools')])
 
+    if not have['tornado']:
+        exclusions.append(ipjoin('frontend', 'html'))
+
     # This is needed for the reg-exp to match on win32 in the ipdoctest plugin.
     if sys.platform == 'win32':
         exclusions = [s.replace('\\','\\\\') for s in exclusions]