Add optional 'fixture' dependencies.

Add extra 'fixture' section so that projects needing to use
oslo_log.fixture can add 'oslo.log [fixture]' to their
requirements to install the fixture dependencies

Closes-Bug: #1493976
Change-Id: I67f3f59c50627a41b672928d037a7bd9997caa11

doc/source/installation.rst

@@ -5,3 +5,8 @@ Installation
 At the command line::
 
     $ pip install oslo.log
+
+To use ``oslo_log.fixture``, some additional dependencies
+are needed. They can be installed using the ``fixtures`` extra::
+
+    $ pip install 'oslo.log[fixtures]'

setup.cfg

@@ -23,6 +23,10 @@ classifier =
 packages =
     oslo_log
 
+[extras]
+fixtures =
+  fixtures>=1.3.1
+
 [pbr]
 warnerrors = true
 

test-requirements.txt

@@ -5,7 +5,6 @@
 hacking<0.11,>=0.10.0
 
 discover
-fixtures>=1.3.1
 python-subunit>=0.0.18
 testrepository>=0.0.18
 testscenarios>=0.4

tox.ini

@@ -14,6 +14,7 @@ setenv =
    VIRTUAL_ENV={envdir}
 deps = -r{toxinidir}/requirements.txt
        -r{toxinidir}/test-requirements.txt
+       -e.[fixtures]
 commands = python setup.py testr --slowest --testr-args='{posargs}'
 
 [testenv:pep8]