Tim Chase wrote:
On 10/07/11 07:38, Peter Otten wrote:
Are there best practices for testing dates that are properties
which take the current date into consideration

The problem is that the behavior of the window_date function
depends on the current date (the function makes a guess about
adding the century if the year was<100).  It *does* take an
"around" parameter that defaults to the current date.  So for
pure testing of the window_date() function, I can hard-code some
date where I know what the expected values should be.

However if I want to write a test-harness for my property, I have
no way (AFAIK) to pass in this fixed date to _set_year_range() so
that the success/failure of my tests doesn't depend on the day I
run them

Temporarily replace the window_date() function with something that you can
control completely. Assuming Foo and window_date are defined in foo.py:

# untested
import foo

class TestFoo:
     def setUp(self):
         foo.window_date = functools.partial(foo.window_date,
around=date(2011, 1, 1))
     def tearDown(self):
         foo.window_date = foo.window_date.func
     def test_year_range(self):
         f = Foo()
         f.year_range = (97, 84)
         self.assertEqual(f.year_range, (1984, 1997))

I had to twiddle my class code a bit to make sure it referenced module.window_date() everywhere instead of just a raw window_date() (originally pulled in via "from module import window_date") so that it picked up the new function, but otherwise it worked like a charm.

Another option is injection:

import foo

def window_date(...):
    ...

foo.window_date = window_date


~Ethan~
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