Added initial tox configuration

Author: astrofrog

tox.ini

@@ -0,0 +1,45 @@
+[tox]
+# We define an environment per package so that we can then run 'tox' on its own
+# and have all packages be tested even if some have failures.
+envlist =
+    # Coordinated packages
+    astropy_healpix
+    astroquery
+    ccdproc
+    photutils
+    regions
+    reproject
+    specutils
+    # Other third-party packages - these are widely used packages that have historically
+    # had issues with some astropy releases, so we include them here as regression testing
+    sunpy
+    lightkurve
+
+requires =
+    setuptools >= 30.3.0
+    pip >= 19.3.1
+isolated_build = true
+
+[testenv]
+pip_pre = true
+# Note that we install all dependencies in all environments to catch any
+# side effects and make sure all test suites pass with all packages
+deps =
+    astropy[all,test]
+    # We can't install 'test' for astropy-healpix as it pins hypothesis
+    # in a way that is not compatible with pytest-astropy
+    # https://github.com/astropy/astropy-healpix/issues/160
+    git+https://github.com/spacetelescope/gwcs#egg_name=gwcs
+    git+https://github.com/astropy/specutils#egg_name=specutils[all,test]
+skip_install = true
+commands =
+    pip freeze
+    astropy_healpix: pytest --pyargs astropy_healpix
+    astroquery: pytest --pyargs astroquery
+    ccdproc: pytest --pyargs ccdproc
+    photutils: pytest --pyargs photutils
+    regions: pytest --pyargs regions
+    reproject: pytest --pyargs reproject
+    specutils: pytest --pyargs specutils
+    sunpy: pytest --pyargs sunpy
+    lightkurve: pytest --pyargs lightkurve