#303 TaurusCommandButton.setParameter fails with empty string

[Carlos Pascual]

To reproduce, execute the following code:

from taurus.qt.qtgui.application import TaurusApplication
from taurus.qt.qtgui.button import TaurusCommandButton

app = TaurusApplication()
w = TaurusCommandButton()
w.setParameters('')

You get (tested on taurus 4 and 3.7):

Traceback (most recent call last):
  File "/home/cpascual/.PyCharm50/config/scratches/scratch_47", line 6, in <module>
    w.setParameters('')
  File "/home/cpascual/src/taurus/lib/taurus/qt/qtgui/button/taurusbutton.py", line 450, in setParameters
    if parameters[0] in ('"', "'") and parameters[0] == parameters[-1]:
IndexError: string index out of range

[Carlos Pascual]

Ticket moved from /p/sardana/tickets/486/

Can't be converted:

• _category: pool