Disable threading in headless test

tests/test_audio.py

@@ -19,8 +19,11 @@ def import_or_mock_pyaudio():
 
 
 def test_audio(import_or_mock_pyaudio):
+    # Cannot run threaded in headless CI because the GUI event loop does not
+    # run and hence no updating takes place :()
+    threaded = os.environ.get('GITLAB_CI', 'False').capitalize() == 'False'
     spect = Spectrometer(QoptColoredNoise(), savepath=mkdtemp(),
-                         play_sound=True)
+                         play_sound=True, threaded_acquisition=threaded)
     spect.take('with sound', f_max=20000, A=2e-4)
     spect.block_until_ready()