[pytest-dev] monkeypatch.setattr of functions and from imports

[Daniel Nouri]

Dear all

I have a function 'somefunc' in module 'a'.  Another module 'b' imports
that function with a "from import":

a.py:

  def somefunc():
      return 'hey!'

b.py:

  from a import somefunc

  def someotherfunc():
      return somefunc() + 'there'


I want to now test 'someotherfunc' while patching away 'somefunc':

  def test_someotherfunc(monkeypatch):
      from b import someotherfunc
      monkeypatch.setattr('a.somefunc', lambda: 'eh?')
      someotherfunc()

But this will fail, since 'b' imported somefunc from 'a' before we
monkey patched the module's attribute.  Without a "from import", this
would work:

b.py:

  import a

  def someotherfunc():
      return a.somefunc() + 'there'

What I would normally resort to is patch somefunc's func_code, so that
even code that used a "from import" before I could patch will use the
patched version.

Thoughts?


Cheers
Daniel