Lib/test/test_sys.py

# -*- coding: iso-8859-1 -*-
import unittest, test.test_support
import sys, io

class SysModuleTest(unittest.TestCase):

    def setUp(self):
        self.orig_stdout = sys.stdout
        self.orig_stderr = sys.stderr
        self.orig_displayhook = sys.displayhook

    def tearDown(self):
        sys.stdout = self.orig_stdout
        sys.stderr = self.orig_stderr
        sys.displayhook = self.orig_displayhook

    def test_original_displayhook(self):
        import __builtin__
        out = io.StringIO()
        sys.stdout = out

        dh = sys.__displayhook__

        self.assertRaises(TypeError, dh)
        if hasattr(__builtin__, "_"):
            del __builtin__._

        dh(None)
        self.assertEqual(out.getvalue(), "")
        self.assert_(not hasattr(__builtin__, "_"))
        dh(42)
        self.assertEqual(out.getvalue(), "42\n")
        self.assertEqual(__builtin__._, 42)

        del sys.stdout
        self.assertRaises(RuntimeError, dh, 42)

    def test_lost_displayhook(self):
        del sys.displayhook
        code = compile("42", "<string>", "single")
        self.assertRaises(RuntimeError, eval, code)

    def test_custom_displayhook(self):
        def baddisplayhook(obj):
            raise ValueError
        sys.displayhook = baddisplayhook
        code = compile("42", "<string>", "single")
        self.assertRaises(ValueError, eval, code)

    def test_original_excepthook(self):
        err = io.StringIO()
        sys.stderr = err

        eh = sys.__excepthook__

        self.assertRaises(TypeError, eh)
        try:
            raise ValueError(42)
        except ValueError as exc:
            eh(*sys.exc_info())

        self.assert_(err.getvalue().endswith("ValueError: 42\n"))

    # FIXME: testing the code for a lost or replaced excepthook in
    # Python/pythonrun.c::PyErr_PrintEx() is tricky.

    def test_exit(self):
        self.assertRaises(TypeError, sys.exit, 42, 42)

        # call without argument
        try:
            sys.exit(0)
        except SystemExit as exc:
            self.assertEquals(exc.code, 0)
        except:
            self.fail("wrong exception")
        else:
            self.fail("no exception")

        # call with tuple argument with one entry
        # entry will be unpacked
        try:
            sys.exit(42)
        except SystemExit as exc:
            self.assertEquals(exc.code, 42)
        except:
            self.fail("wrong exception")
        else:
            self.fail("no exception")

        # call with integer argument
        try:
            sys.exit((42,))
        except SystemExit as exc:
            self.assertEquals(exc.code, 42)
        except:
            self.fail("wrong exception")
        else:
            self.fail("no exception")

        # call with string argument
        try:
            sys.exit("exit")
        except SystemExit as exc:
            self.assertEquals(exc.code, "exit")
        except:
            self.fail("wrong exception")
        else:
            self.fail("no exception")

        # call with tuple argument with two entries
        try:
            sys.exit((17, 23))
        except SystemExit as exc:
            self.assertEquals(exc.code, (17, 23))
        except:
            self.fail("wrong exception")
        else:
            self.fail("no exception")

        # test that the exit machinery handles SystemExits properly
        import subprocess
        rc = subprocess.call([sys.executable, "-c",
                              "raise SystemExit(47)"])
        self.assertEqual(rc, 47)

    def test_getdefaultencoding(self):
        self.assertRaises(TypeError, sys.getdefaultencoding, 42)
        # can't check more than the type, as the user might have changed it
        self.assert_(isinstance(sys.getdefaultencoding(), str))

    # testing sys.settrace() is done in test_trace.py
    # testing sys.setprofile() is done in test_profile.py

    def test_setcheckinterval(self):
        self.assertRaises(TypeError, sys.setcheckinterval)
        orig = sys.getcheckinterval()
        for n in 0, 100, 120, orig: # orig last to restore starting state
            sys.setcheckinterval(n)
            self.assertEquals(sys.getcheckinterval(), n)

    def test_recursionlimit(self):
        self.assertRaises(TypeError, sys.getrecursionlimit, 42)
        oldlimit = sys.getrecursionlimit()
        self.assertRaises(TypeError, sys.setrecursionlimit)
        self.assertRaises(ValueError, sys.setrecursionlimit, -42)
        sys.setrecursionlimit(10000)
        self.assertEqual(sys.getrecursionlimit(), 10000)
        sys.setrecursionlimit(oldlimit)

    def test_getwindowsversion(self):
        if hasattr(sys, "getwindowsversion"):
            v = sys.getwindowsversion()
            self.assert_(isinstance(v, tuple))
            self.assertEqual(len(v), 5)
            self.assert_(isinstance(v[0], int))
            self.assert_(isinstance(v[1], int))
            self.assert_(isinstance(v[2], int))
            self.assert_(isinstance(v[3], int))
            self.assert_(isinstance(v[4], str))

    def test_dlopenflags(self):
        if hasattr(sys, "setdlopenflags"):
            self.assert_(hasattr(sys, "getdlopenflags"))
            self.assertRaises(TypeError, sys.getdlopenflags, 42)
            oldflags = sys.getdlopenflags()
            self.assertRaises(TypeError, sys.setdlopenflags)
            sys.setdlopenflags(oldflags+1)
            self.assertEqual(sys.getdlopenflags(), oldflags+1)
            sys.setdlopenflags(oldflags)

    def test_refcount(self):
        self.assertRaises(TypeError, sys.getrefcount)
        c = sys.getrefcount(None)
        n = None
        self.assertEqual(sys.getrefcount(None), c+1)
        del n
        self.assertEqual(sys.getrefcount(None), c)
        if hasattr(sys, "gettotalrefcount"):
            self.assert_(isinstance(sys.gettotalrefcount(), int))

    def test_getframe(self):
        self.assertRaises(TypeError, sys._getframe, 42, 42)
        self.assertRaises(ValueError, sys._getframe, 2000000000)
        self.assert_(
            SysModuleTest.test_getframe.im_func.__code__ \
            is sys._getframe().f_code
        )

    # sys._current_frames() is a CPython-only gimmick.
    def test_current_frames(self):
        have_threads = True
        try:
            import thread
        except ImportError:
            have_threads = False

        if have_threads:
            self.current_frames_with_threads()
        else:
            self.current_frames_without_threads()

    # Test sys._current_frames() in a WITH_THREADS build.
    def current_frames_with_threads(self):
        import threading, thread
        import traceback

        # Spawn a thread that blocks at a known place.  Then the main
        # thread does sys._current_frames(), and verifies that the frames
        # returned make sense.
        entered_g = threading.Event()
        leave_g = threading.Event()
        thread_info = []  # the thread's id

        def f123():
            g456()

        def g456():
            thread_info.append(thread.get_ident())
            entered_g.set()
            leave_g.wait()

        t = threading.Thread(target=f123)
        t.start()
        entered_g.wait()

        # At this point, t has finished its entered_g.set(), although it's
        # impossible to guess whether it's still on that line or has moved on
        # to its leave_g.wait().
        self.assertEqual(len(thread_info), 1)
        thread_id = thread_info[0]

        d = sys._current_frames()

        main_id = thread.get_ident()
        self.assert_(main_id in d)
        self.assert_(thread_id in d)

        # Verify that the captured main-thread frame is _this_ frame.
        frame = d.pop(main_id)
        self.assert_(frame is sys._getframe())

        # Verify that the captured thread frame is blocked in g456, called
        # from f123.  This is a litte tricky, since various bits of
        # threading.py are also in the thread's call stack.
        frame = d.pop(thread_id)
        stack = traceback.extract_stack(frame)
        for i, (filename, lineno, funcname, sourceline) in enumerate(stack):
            if funcname == "f123":
                break
        else:
            self.fail("didn't find f123() on thread's call stack")

        self.assertEqual(sourceline, "g456()")

        # And the next record must be for g456().
        filename, lineno, funcname, sourceline = stack[i+1]
        self.assertEqual(funcname, "g456")
        self.assert_(sourceline in ["leave_g.wait()", "entered_g.set()"])

        # Reap the spawned thread.
        leave_g.set()
        t.join()

    # Test sys._current_frames() when thread support doesn't exist.
    def current_frames_without_threads(self):
        # Not much happens here:  there is only one thread, with artificial
        # "thread id" 0.
        d = sys._current_frames()
        self.assertEqual(len(d), 1)
        self.assert_(0 in d)
        self.assert_(d[0] is sys._getframe())

    def test_attributes(self):
        self.assert_(isinstance(sys.api_version, int))
        self.assert_(isinstance(sys.argv, list))
        self.assert_(sys.byteorder in ("little", "big"))
        self.assert_(isinstance(sys.builtin_module_names, tuple))
        self.assert_(isinstance(sys.copyright, str))
        self.assert_(isinstance(sys.exec_prefix, str))
        self.assert_(isinstance(sys.executable, str))
        self.assert_(isinstance(sys.hexversion, int))
        self.assert_(isinstance(sys.maxint, int))
        self.assert_(isinstance(sys.maxunicode, int))
        self.assert_(isinstance(sys.platform, str))
        self.assert_(isinstance(sys.prefix, str))
        self.assert_(isinstance(sys.version, str))
        vi = sys.version_info
        self.assert_(isinstance(vi, tuple))
        self.assertEqual(len(vi), 5)
        self.assert_(isinstance(vi[0], int))
        self.assert_(isinstance(vi[1], int))
        self.assert_(isinstance(vi[2], int))
        self.assert_(vi[3] in ("alpha", "beta", "candidate", "final"))
        self.assert_(isinstance(vi[4], int))

    def test_43581(self):
        # Can't use sys.stdout, as this is a cStringIO object when
        # the test runs under regrtest.
        self.assertEqual(sys.__stdout__.encoding, sys.__stderr__.encoding)

    def test_intern(self):
        self.assertRaises(TypeError, sys.intern)
        s = "never interned before"
        self.assert_(sys.intern(s) is s)
        s2 = s.swapcase().swapcase()
        self.assert_(sys.intern(s2) is s)

        # Subclasses of string can't be interned, because they
        # provide too much opportunity for insane things to happen.
        # We don't want them in the interned dict and if they aren't
        # actually interned, we don't want to create the appearance
        # that they are by allowing intern() to succeeed.
        class S(str):
            def __hash__(self):
                return 123

        self.assertRaises(TypeError, sys.intern, S("abc"))


def test_main():
    test.test_support.run_unittest(SysModuleTest)

if __name__ == "__main__":
    test_main()