Index: psi4/tests/runtest.py
===================================================================
--- psi4.orig/tests/runtest.py
+++ psi4/tests/runtest.py
@@ -118,7 +118,7 @@ elif os.path.isfile(infile.replace(".dat
     else:
         os.environ["PYTHONPATH"] = psilibdir
     outfile = os.path.dirname(infile) + os.path.sep + outfile
-    pyexitcode = backtick(["python", infile, " > ", outfile])
+    pyexitcode = backtick(["python3", infile, " > ", outfile])
 else:
     raise Exception("\n\nError: Input file %s not found\n" % infile)