Fix CI issues

Author: astrofrog

.travis.yml

@@ -31,12 +31,16 @@ matrix:
       env: TOXENV=codestyle
     # Also test the oldest and newest configuration on Mac and Windows
     - os: osx
+      language: c
       env: PYTHON_VERSION=2.7 TOXENV=py27-test-mpl15
     - os: osx
+      language: c
       env: PYTHON_VERSION=3.8 TOXENV=py38-test-mpl31
     - os: windows
+      language: c
       env: PYTHON_VERSION=2.7 TOXENV=py27-test-mpl15
     - os: windows
+      language: c
       env: PYTHON_VERSION=3.8 TOXENV=py38-test-mpl31
 
 install:

tox.ini

@@ -12,7 +12,9 @@ changedir = .tmp/{envname}
 description = run tests
 deps =
     mpl15: matplotlib==1.5.*
+    mpl15: nose
     mpl20: matplotlib==2.0.*
+    mpl20: nose
     mpl21: matplotlib==2.1.*
     mpl22: matplotlib==2.2.*
     mpl30: matplotlib==3.0.*