[Pytest-commit] Issue #635: Fixture scope is non-deterministic (hpk42/pytest)

[Nikolaus Rath]

New issue 635: Fixture scope is non-deterministic
https://bitbucket.org/hpk42/pytest/issue/635/fixture-scope-is-non-deterministic

Nikolaus Rath:

Consider the attached test case. Both fixtures are defined with module scope, so they should be called just once for each parameter value.

However, sometimes the "bar" fixture is called twice for the same parameter value. Example:

```
#!

$ py.test-3 test_bug.py -s
============================= test session starts =============================
platform linux -- Python 3.4.2 -- py-1.4.25 -- pytest-2.6.3
plugins: capturelog, ordering
collected 4 items 

test_bug.py preparing bar-1
preparing bar-1/foo-1
.preparing bar-2
preparing bar-2/foo-1
.preparing bar-2/foo-2
.preparing bar-1
preparing bar-1/foo-2
.

========================== 4 passed in 0.01 seconds ===========================

$ py.test-3 test_bug.py -s
============================= test session starts =============================
platform linux -- Python 3.4.2 -- py-1.4.25 -- pytest-2.6.3
plugins: capturelog, ordering
collected 4 items 

test_bug.py preparing bar-1
preparing bar-1/foo-1
.preparing bar-1/foo-2
.preparing bar-2
preparing bar-2/foo-2
.preparing bar-2/foo-1
.

========================== 4 passed in 0.01 seconds ===========================

```

I think the number of calls to a fixture should be determinstic and reproducible.

Moreover, I think the second run (where "preparing bar-1" is printed only once) is  correct.