[Tutor] unittest with random population data

[Sydney Shall]

MAC OSX 10.10.3
Enthought Python 2.7

I am an almost beginner.

Following advice from you generous people, I have chosen a project that 
interests me, to develop some knowledge of python.
My projest is a simulation of a biological population.
I have a base class and a simulation function, which uses instances of 
the class.
This, after many months of work and lots of advice, now seems to work 
well. It generates sensible data and when I write a small test program 
it gives sensible output.
Now I want to learn to use unittest.
I have written a unittest class which works OK.
But the problem I have is that because I use the random module to 
populate my initial arrays, my data is not strictly predictable even 
though I am using seed(0). So the tests return many *fails* because the 
numbers are not exactly correct, although they are all rather close, 
consistent with the sigma value I have chosen for the spread of my 
population. I do of course use *almostEqual* and not *Equal*.
So, I would be very grateful for guidance. How does one proceed in this 
case? Should I simply create an arbitrary array or value to input into 
the function that I want to test?
I would be grateful for any guidance.

-- 
Sydney