[Tutor] unittest for: Raises an exception

[Sydney Shall]

I use a MAC OSX 10.9.5
Enthought Canopy Python 2.7.6

I am a learner.

I am now trying to learn unittests as is often emphasised on this list.
I think that I have understood the simple unit tests such as Equal, 
Greater etc.
But I am struggling with the syntax of a test for Raises an exception.

The function that I am tring to test is:
For some reason my indentation has not been correctly copied.
I am sure that it is correct becuase I have chacked it as well as the 
program. Also the 20 tests that are OK refer to all the other functions 
in the program.

def getSurplusLabourTime(self, ww, uvc):
     self.ww = ww
          self.uvc = uvc
          try:
             self.surplus_labour_time = self.ww - self.uvc
             return self.surplus_labour_time
          except:
             if self.surplus_labour_time <= 0.0:
                 raise ValueError("Surplus labour time cannot be" + \
                     " equal to or shorter than zero!")

My test code is the following:

def test_func_getSurplusLabourTime_Exc(self):
 
self.assertRaises(ValueError,self.cwp.getSurplusLabourTime(self.cwp.ww,self.cwp.uvc)) 

[This last line should indented, but it refuses to do so!]

The traceback is as follows:

======================================================================
ERROR: test_func_getSurplusLabourTime_Exc (__main__.Testcwp)
----------------------------------------------------------------------
Traceback (most recent call last):
   File 
"/Users/sydney/My_Documents/Political_Economy/Capital_Simulation/Capital/Current 
version/TestCWP_WorkDuration.py", line 88, in 
test_func_getSurplusLabourTime_Exc
     self.assertRaises(ValueError, 
self.cwp.getSurplusLabourTime(self.cwp.ww, self.cwp.uvc))
   File 
"/Applications/Canopy.app/appdata/canopy-1.5.1.2730.macosx-x86_64/Canopy.app/Contents/lib/python2.7/unittest/case.py", 
line 475, in assertRaises
     callableObj(*args, **kwargs)
TypeError: 'float' object is not callable

----------------------------------------------------------------------
Ran 21 tests in 0.005s

FAILED (errors=1)


I do know that I have not added the arguments that would sause an 
exception to be raised. But I have tried several forms and none have 
worked. I get the same traceback as above.


Any guidance would be appreciated.



-- 
Sydney