Make sure we directly install mpl for py3.5

.gitignore

@@ -45,10 +45,10 @@ distribute-*.tar.gz
 .coverage
 cover
 htmlcov
+.pytest_cache
 
 # Mac OSX
 .DS_Store
 
 # PyCharm
 .idea
-

.travis.yml

@@ -18,11 +18,11 @@ env:
       CONDA_DEPENDENCIES='sphinx cython numpy pytest-cov'
       EVENT_TYPE='push pull_request cron'
 
-
   global:
     - CONDA_DEPENDENCIES="setuptools sphinx cython numpy pytest-cov"
     - PIP_DEPENDENCIES="codecov"
     - EVENT_TYPE='push pull_request'
+    - DEBUG=True
 
 matrix:
   include:
@@ -46,15 +46,15 @@ matrix:
     - os: osx
       env:
         - PYTHON_VERSION=3.5
-        - CONDA_DEPENDENCIES="setuptools sphinx cython numpy pytest-cov clang llvm-openmp"
+        - CONDA_DEPENDENCIES="setuptools sphinx cython numpy pytest-cov clang llvm-openmp matplotlib"
         - OPENMP_EXPECTED=True
         - CCOMPILER=clang
 
     # Test gcc on OSX
     - os: osx
       env:
         - PYTHON_VERSION=3.5
-        - CONDA_DEPENDENCIES="setuptools sphinx cython numpy pytest-cov gcc"
+        - CONDA_DEPENDENCIES="setuptools sphinx cython numpy pytest-cov gcc sphinx-astropy"
         - OPENMP_EXPECTED=True
         - CCOMPILER=gcc
 

astropy_helpers/commands/build_sphinx.py

@@ -57,6 +57,14 @@ def ensure_sphinx_astropy_installed():
 
         from setuptools import Distribution
         dist = Distribution()
+
+        # This egg build doesn't respect python_requires, not aware of
+        # pre-releases. We know that mpl 3.1+ requires Python 3.6+, so this
+        # ugly workaround takes care of it until there is a solution for
+        # https://github.com/astropy/astropy-helpers/issues/462
+        if LooseVersion(sys.version) < LooseVersion('3.6'):
+            dist.fetch_build_eggs('matplotlib<3.1')
+
         eggs = dist.fetch_build_eggs('sphinx-astropy')
 
         # Find out the version of sphinx-astropy if possible. For some old