Improve Travis / tox setup + coverage (#851)

* Improve Travis / tox setup

Mainly inspired by using pytest directly in tox, for easy test selection
etc.

* Travis: use lightweight containers (sudo=false)

* coverage/codecov integration

* include TEST_EXTRA as codecov flag

* codecov: -X fix

This hopefully works around `complex/complex/commands/__init__.py` and
`termui/termui.py` showing up in `examples` (at the root).

1 files changed, 6 insertions, 4 deletions

diff --git a/tox.ini b/tox.ini
index 91bef64..de1fb38 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,10 +1,12 @@
 [tox]
-envlist = py26,py27,py33,py34,pypy
+envlist = py{26,27,33,34,35,36,py}
 
 [testenv]
 passenv = LANG
-commands = make test
+commands = {env:TEST_RUNNER:pytest} {posargs}
 deps =
-    colorama
     pytest
-whitelist_externals = make
+    colorama: colorama
+    coverage: coverage
+setenv =
+    coverage: TEST_RUNNER=coverage run -m pytest