fix pytest call

tox.ini

@@ -35,7 +35,7 @@ deps =
 
     # The oldestdeps factor is intended to be used to install the oldest versions of all
     # dependencies that have a minimum version.
-    oldestdeps: numpy==1.16.*
+    oldestdeps: numpy==1.17.*
     oldestdeps: scipy==1.1.*
     oldestdeps: astropy==3.2.*
 
@@ -54,7 +54,10 @@ extras =
 commands =
     pip freeze
     !cov: pytest --pyargs synphot {toxinidir}/docs {posargs}
-    cov: pytest --rootdir={toxinidir} -c {toxinidir}/setup.cfg  --pyargs {posargs:synphot} --cov={envsitepackagesdir}/synphot --cov-config={toxinidir}/setup.cfg {posargs} --cov-report xml:{toxinidir}/coverage.xml
+    # FIXME: Seems like using -c option with multiline Pytest is broken: see
+    # https://github.com/tox-dev/tox-travis/issues/146
+    # at the very least on CI - it runs fine locally on MacOSX.
+    cov: pytest --rootdir={toxinidir} -c {toxinidir}/setup.cfg --pyargs synphot --cov={envsitepackagesdir}/synphot --cov-config={toxinidir}/setup.cfg {posargs} --cov-report xml:{toxinidir}/coverage.xml
 
 [testenv:codestyle]
 skip_install = true