Django testcase for render()

Hi I'm new to Django and I'm trying to write some unit test cases for given function. Can anyone give me a sample unit test cases for this function? THANKS!!

This is the function in views.py:

def signin(request):
    error = ""
    if request.method == 'POST':
        user = authenticate(username=request.POST.get("username",""), password=request.POST.get("password",""))
        if user is not None: 
            if user.is_active:
                login(request, user)
                return HttpResponseRedirect("/bet/")
        error="Unable to login."

    form = SigninForm(auto_id=False)
    return render(request, 'frontend/signin.html', context_instance=RequestContext(request, {'form': form, 'error': error}))