Yup, psutil still causes problems on travis ci.

dev-requirements.txt

@@ -7,7 +7,9 @@ coverage>=4.0
 coveralls>=1.0
 cffi
 futures
-psutil
+# Makes tests faster, but causes issues on the old
+# linux version Travis CI uses.
+# psutil
 # For viewing README.rst (restview --long-description),
 # CONTRIBUTING.rst, etc.
 # https://github.com/mgedmin/restview

src/greentest/greentest.py

@@ -695,6 +695,7 @@ else:
     # (Running 14 tests takes 3.964s with lsof and 0.046 with psutil)
     # However, it still doesn't completely solve the issue on Windows: fds are reported
     # as -1 there, so we can't fully check those.
+    # XXX: Note: installing psutil on the travis linux vm caused failures in test__makefile_refs.
 
     def get_open_files():
         results = dict()