Skip the rlimit_ctrl_c and rlimit_forground tests if you're not using…

… tox.

These tests need ptyprocess to run, so they always fail in a production environment.

tests/tests_e3/os/process/main_test.py

@@ -155,6 +155,9 @@ def test_rlimit_ctrl_c():
                 The foreground process has been killed, leaving no foreground process.
                 Signals were no longer propagated, so CTRL-C did nothing.
     """
+    if "TOX_ENV_NAME" not in os.environ:
+        return
+
     try:
         from ptyprocess import PtyProcess
     except ImportError:
@@ -195,6 +198,9 @@ def test_rlimit_foreground_option():
 
     Test if we can read/write from an interactive terminal using rlimit --foreground.
     """
+    if "TOX_ENV_NAME" not in os.environ:
+        return
+
     try:
         from ptyprocess import PtyProcess
     except ImportError: