split up the plugin and extend tox test matrix

tox.ini

@@ -1,43 +1,28 @@
 [tox]
-envlist=py26,py33,py34,py27,py27-pexpect,py33-pexpect,py26-old,py33-old,flakes
+envlist=
+  py{26,33,34,27}-pytest2{4,5,6,7},py{27,34}-pytest27-pexpect,flakes
+
 
 [testenv]
 changedir=testing
-deps=pytest>=2.5.1
-commands= py.test {posargs}
+deps =
+    pycmd
+    pytest24: pytest~=2.4.0
+    pytest25: pytest~=2.5.0
 
-[testenv:py27-pexpect]
-deps={[testenv]deps}
-    pexpect
-[testenv:py33-pexpect]
-deps={[testenv]deps}
-    pexpect
+    pytest26: pytest~=2.6.1
+    pytest27: pytest~=2.7.2
+    pexpect: pexpect
+commands=
+  # always clean to avoid code unmarshal mismatch on old python/pytest
+  py.cleanup -aq
+  py.test {posargs}
 
 [testenv:flakes]
 changedir=
 deps = pytest-flakes>=0.2
 commands = py.test --flakes -m flakes testing xdist
 
-[testenv:py26-old]
-basepython = python2.6
-deps=
-    pytest==2.5.2
-    pycmd
-
-commands= 
-    py.cleanup -a
-    py.test {posargs}
-
-[testenv:py33-old]
-basepython = python3.3
-deps=
-    pytest==2.5.2
-    pycmd
-
-commands= 
-    py.cleanup -a
-    py.test {posargs}
-
 [pytest]
 addopts = -rsfxX
 ;; hello