Add tests.saltunittest.RedirectStdStreams.

* The `RedirectStdStreams` tests helper will allow to temporarily catch `stdout` and `stderr` output. Right now it's only used to **mute** the `tests.integration.runners.jobs.ManageTest.test_active()` output.

tests/integration/__init__.py

@@ -24,7 +24,7 @@ import salt.minion
 import salt.runner
 from salt.utils import get_colors
 from salt.utils.verify import verify_env
-from saltunittest import TestCase
+from saltunittest import TestCase, RedirectStdStreams
 
 try:
     import console
@@ -641,8 +641,9 @@ class ShellCase(TestCase):
             os.path.join(INTEGRATION_TEST_DIR, 'files', 'conf', 'master')
         )
         opts.update({'doc': False, 'fun': fun, 'arg': arg})
-        runner = salt.runner.Runner(opts)
-        ret['fun'] = runner.run()
+        with RedirectStdStreams():
+            runner = salt.runner.Runner(opts)
+            ret['fun'] = runner.run()
         return ret
 
     def run_key(self, arg_str, catch_stderr=False):

tests/saltunittest.py

@@ -13,6 +13,9 @@ import sys
 import logging
 from functools import wraps
 
+# Import salt libs
+from salt.utils import fopen
+
 # support python < 2.7 via unittest2
 if sys.version_info[0:2] < (2, 7):
     try:
@@ -55,6 +58,48 @@ def destructiveTest(func):
     return wrap
 
 
+class RedirectStdStreams(object):
+    """
+    Temporarily redirect system output to file like objects.
+    Default is to redirect to `os.devnull`, which just mutes output, `stdout`
+    and `stderr`.
+    """
+
+    def __init__(self, stdout=None, stderr=None):
+        if stdout is None:
+            stdout = fopen(os.devnull, 'w')
+        if stderr is None:
+            stderr = fopen(os.devnull, 'w')
+
+        self.__stdout = stdout
+        self.__stderr = stderr
+        self.__redirected = False
+
+    def __enter__(self):
+        self.redirect()
+
+    def __exit__(self, exc_type, exc_value, traceback):
+        self.unredirect()
+
+    def redirect(self):
+        self.old_stdout = sys.stdout
+        self.old_stdout.flush()
+        self.old_stderr = sys.stderr
+        self.old_stderr.flush()
+        sys.stdout = self.__stdout
+        sys.stderr = self.__stderr
+        self.__redirected = True
+
+    def unredirect(self):
+        if not self.__redirected:
+            return
+
+        self.__stdout.flush()
+        self.__stderr.flush()
+        sys.stdout = self.old_stdout
+        sys.stderr = self.old_stderr
+
+
 class TestsLoggingHandler(object):
     '''
     Simple logging handler which can be used to test if certain logging