Surpressing stdout/stderr from opening web browsers

requirements.txt

@@ -4,6 +4,6 @@ kitchen==1.2.4
 mailcap-fix==0.1.3
 requests==2.11.0
 six==1.10.0
-pytest==3.0.7
+pytest==3.2.3
 vcrpy==1.10.5
 pylint==1.6.5

rtv/terminal.py

@@ -513,9 +513,21 @@ class Terminal(object):
                     # can re-use the webbrowser instance that has been patched
                     # by RTV. It's also safer because it doesn't inject
                     # python code through the command line.
-                    null = open(os.devnull, 'ab+', 0)
-                    sys.stdout, sys.stderr = null, null
+
+                    # Surpress stdout/stderr from the browser, see
+                    # https://stackoverflow.com/questions/2323080. We can't
+                    # depend on replacing sys.stdout & sys.stderr because
+                    # webbrowser uses Popen().
+                    stdout, stderr = os.dup(1), os.dup(2)
+                    null = os.open(os.devnull, os.O_RDWR)
+                    try:
+                        os.dup2(null, 1)
+                        os.dup2(null, 2)
                         webbrowser.open_new_tab(url)
+                    finally:
+                        null.close()
+                        os.dup2(stdout, 1)
+                        os.dup2(stderr, 2)
 
                 p = Process(target=open_url_silent, args=(url,))
                 p.start()