test_stderr fails because stderr is "sh: sysctl command not found" when it should be empty about marbles HOT 9 CLOSED

(marbles-rOKSo-69) jane@19:06:40 core (master *) $ python -m unittest tests.test_main.VersionTestCase.test_stderr
['/Users/jane/Environments/marbles-rOKSo-69/bin/python', '-m', 'marbles', '--version']
F
======================================================================
FAIL: test_stderr (tests.test_main.VersionTestCase)
The error output should be empty.
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/Users/jane/Development/marbles/marbles/core/tests/test_main.py", line 255, in test_stderr
    self.assertEqual('', self.stderr)
AssertionError: '' != 'sh: sysctl: command not found\n'
+ sh: sysctl: command not found


----------------------------------------------------------------------
Ran 1 test in 0.350s

FAILED (failures=1)
(marbles-rOKSo-69) jane@19:06:48 core (master *) $ git diff tests/test_main.py
diff --git a/marbles/core/tests/test_main.py b/marbles/core/tests/test_main.py
index 2b9deca..507a4ff 100644
--- a/marbles/core/tests/test_main.py
+++ b/marbles/core/tests/test_main.py
@@ -251,6 +251,7 @@ class VersionTestCase(CommandRunningTestCase):
 
     def test_stderr(self):
         '''The error output should be empty.'''
+        print(self.cmd)
         self.assertEqual('', self.stderr)

(marbles-rOKSo-69) jane@19:10:06 core (master *) $ git diff tests/test_main.py
diff --git a/marbles/core/tests/test_main.py b/marbles/core/tests/test_main.py
index 2b9deca..1221d2e 100644
--- a/marbles/core/tests/test_main.py
+++ b/marbles/core/tests/test_main.py
@@ -86,7 +86,7 @@ class CommandRunningTestCase(unittest.TestCase):
             to_remove = None
         try:
             proc = subprocess.run(
-                self.cmd, stdout=subprocess.PIPE, stderr=subprocess.PIPE,
+                ' '.join(self.cmd), shell=True, stdout=subprocess.PIPE, stderr=subprocess.PIPE,
                 env=env, cwd=core_dir)
         finally:
             if to_remove:
@@ -251,6 +251,7 @@ class VersionTestCase(CommandRunningTestCase):
 
     def test_stderr(self):
         '''The error output should be empty.'''
+        print(self.cmd)
         self.assertEqual('', self.stderr)

(marbles-rOKSo-69) jane@19:22:03 marbles (master) $ /Users/jane/Environments/marbles-rOKSo-69/bin/python -m marbles --version
marbles.core version: 0.9.2
marbles.mixins version: 0.9.2