Use separate tox target for coverage

.travis.yml

@@ -18,6 +18,7 @@ env:
     - TOXENV=flakeplus
     - TOXENV=apicheck
     - TOXENV=configcheck
+    - TOXENV=cov
 before_install:
     - |
           if [ "$TOXENV" = "pypy" ]; then

tox.ini

@@ -1,12 +1,12 @@
 [tox]
-envlist = 2.7,pypy,3.4,3.5,pypy3,flake8,flakeplus,apicheck,configcheck
+envlist = 2.7,pypy,3.4,3.5,pypy3,flake8,flakeplus,apicheck,configcheck,cov
 
 [testenv]
 deps=
     -r{toxinidir}/requirements/default.txt
     -r{toxinidir}/requirements/test.txt
 
-    2.7: -r{toxinidir}/requirements/test-ci-default.txt
+    2.7,cov: -r{toxinidir}/requirements/test-ci-default.txt
     3.4,3.5: -r{toxinidir}/requirements/test-ci-default.txt
     pypy,pypy3: -r{toxinidir}/requirements/test-ci-base.txt
 
@@ -15,15 +15,20 @@ deps=
 sitepackages = False
 recreate = False
 commands = pip install -U -r{toxinidir}/requirements/dev.txt
-           py.test -x --cov=celery --cov-report=html
+           py.test -xv
 
 basepython =
-    2.7,flake8,flakeplus,apicheck,linkcheck,configcheck: python2.7
+    2.7,flake8,flakeplus,apicheck,linkcheck,configcheck,cov: python2.7
     3.4: python3.4
     3.5: python3.5
     pypy: pypy
     pypy3: pypy3
 
+[testenv:cov]
+commands =
+    pip install -U -r{toxinidir}/requirements/dev.txt
+    py.test -xv --cov=celery --cov-report=xml
+
 [testenv:apicheck]
 commands =
     pip install -U -r{toxinidir}/requirements/dev.txt