add a better Description for PyPI

README.rst

@@ -2,6 +2,49 @@
 RestrictedPython
 ================
 
-RestrictedPython is a defined subset of the Python language which allows to provide a program input into a trusted environment.
+RestrictedPython is a tool that helps to define a subset of the Python language which allows to provide a program input into a trusted environment.
+RestrictedPython is not a sandbox system or a secured environment, but it helps to define a trusted environment and execute untrusted code inside of it.
 
 For full documentation please see  http://restrictedpython.readthedocs.io/ or the local ``docs/index``.
+
+Example
+=======
+
+To give a basic understanding what RestrictedPython does here two examples:
+
+An unproblematic code example
+-----------------------------
+
+Python allows you to execute a large set of commands.
+This would not harm any system.
+
+    >>> from RestrictedPython import compile_restricted
+    >>> from RestrictedPython import safe_builtins
+    >>>
+    >>> source_code = """
+    ... def example():
+    ...     return 'Hello World!'
+    ... """
+    >>>
+    >>> loc = {}
+    >>> byte_code = compile_restricted(source_code, '<inline>', 'exec')
+    >>> exec(byte_code, safe_builtins, loc)
+    >>>
+    >>> loc['example']()
+    'Hello World!'
+
+Problematic code example
+------------------------
+
+This example directly executed in Python could harm your system.
+
+  >>> from RestrictedPython import compile_restricted
+  >>> from RestrictedPython import safe_builtins
+  >>>
+  >>> source_code = """
+  ... import os
+  ...
+  ... os.listdir('/')
+  ... """
+  >>> byte_code = compile_restricted(source_code, '<inline>', 'exec')
+  >>> # exec(byte_code, safe_builtins, {})

docs/CHANGES.rst

@@ -4,7 +4,10 @@ Changes
 4.0a2 (unreleased)
 ------------------
 
+- Modified README and setup.py to provide a better desciption test for PyPI.
+  [loechel]
 - Drop support for long-deprecated ``sets`` module.
+  [tseaver]
 
 
 4.0a1 (2017-05-05)

setup.py

@@ -27,8 +27,9 @@ def read(*rnames):
       version='4.0a2.dev0',
       url='http://pypi.python.org/pypi/RestrictedPython',
       license='ZPL 2.1',
-      description='RestrictedPython provides a restricted execution '
-                  'environment for Python, e.g. for running untrusted code.',
+      description='RestrictedPython is a defined subset of the Python '
+                  'language which allows to provide a program input into '
+                  'a trusted environment.',
       long_description=(read('README.rst') + '\n' +
                         read('docs', 'CHANGES.rst')),
       classifiers=[

tests/test_imports.py

@@ -0,0 +1,32 @@
+"""
+Tests about imports
+"""
+
+from RestrictedPython import safe_builtins
+from tests import c_exec
+from tests import e_exec
+
+import pytest
+
+
+OS_IMPORT_EXAMPLE = """
+import os
+
+os.listdir('/')
+"""
+
+
+@pytest.mark.parametrize(*c_exec)
+@pytest.mark.parametrize(*e_exec)
+def test_os_import(c_exec, e_exec):
+    """Test that import should not work out of the box.
+    TODO: Why does this work.
+    """
+    result = c_exec(OS_IMPORT_EXAMPLE, safe_builtins)
+    # TODO: there is a tests/__init__.py problem, as it seems to pass the
+    #       safe_builtins into the compile function instead of the source.
+    assert result.code is None
+    # assert result.errors == ()
+
+    with pytest.raises(NameError):
+        e_exec(OS_IMPORT_EXAMPLE, safe_builtins)