[WIP] testing travis windows again

.travis.yml

@@ -1,21 +1,16 @@
 dist: xenial
 
-language: r
-
-r: release
+language: minimal
 
 matrix:
   include:
-  - os: linux
-    env: PYENV=py37
-  - os: osx
-    env: PYENV=py37
-# turn these on once travis support gets a little better, see pyam for example
-#  - os: windows
+#  - os: linux
 #    env: PYENV=py37
-
-r_packages:
-- IRkernel
+#  - os: osx
+#    env: PYENV=py37
+# turn these on once travis support gets a little better, see pyam for example
+  - os: windows
+    env: PYENV=py37
 
 cache:
   # Travis ensures these directories are created if they do not already exist
@@ -40,15 +35,13 @@ before_install:
 install:
   - source ci/travis-install.sh
   - pip install .[docs,tests,tutorial]
-  - Rscript -e 'devtools::install("rixmp", dep = T)'
 
 script:
   - python -c "import os, sys; assert os.environ['PYVERSION'] == sys.version[0]"
   # Run tests
   # These include the equivalent of Travis R tests via test_r.py
   - >
     pytest
-    --testr
     --verbose
     --cov=ixmp
     --cov-config ci/.coveragerc