[Tutor] Puzzling case of assertRaises not running properly

[Martin A. Brown]

Hello,

Overall, I must say.... good work and your question was clear.

>Learning about how to write tests in Python and have a query.

Excellent!

I will snip everything except where I think you should look...

   def check_input(self, seat1, app1):
     try:
        seat1 = float(seat1)
        app1 = float(app1)
     except ValueError:
         print "Not a float"
     return (seat1, app1)

You have a try / except block here and your test is deliberately 
attempting to trigger the ValueError.  That is good.

But, in the except handling, you simply print something and you do 
not re-raise the error.  So, Python thinks you have caught the 
Exception, done what you needed and will continue program flow.

If you wish to propagate the exception (instead of catching it and 
handling it), you could consider something like the following:

   def check_input(self, seat1, app1):
     try:
        seat1 = float(seat1)
        app1 = float(app1)
     except ValueError:
         print "Not a float"
         raise
     return (seat1, app1)

[I will observe that in your __name__ == '__main__' code, you are 
using the print_function, but in your except handling, you are using 
the print statement.  You probably want to pick one.  And, I would 
recommend the print_function--something that seems you already have 
a handle on.]

>if __name__=='__main__':
>     bill = Bill()
>     (total, tax) =  bill.bill(2,3)
>     print("tax $%.2f" % tax)
>     print("total charge for meal $%.2f" % total)


>if __name__=='__main__':
>   unittest.main()
>
>I'm using Python 2.7.
>
>When I run the test doing python bill_test.py -v, I get the following
>result:-
>
>test_bill_pay_3_4 (__main__.BillTest) ... ok
>test_input_not_float_raises_ValueError (__main__.BillTest) ... Not a float
>FAIL

Good luck!

-Martin

-- 
Martin A. Brown
http://linux-ip.net/