cpython/Lib/test/test_capi.py

# Run the _testcapi module tests (tests for the Python/C API):  by defn,
# these are all functions _testcapi exports whose name begins with 'test_'.

import os
import pickle
import random
import subprocess
import sys
import time
import unittest
from test import support
try:
    import _posixsubprocess
except ImportError:
    _posixsubprocess = None
try:
    import threading
except ImportError:
    threading = None
import _testcapi


def testfunction(self):
    """some doc"""
    return self

class InstanceMethod:
    id = _testcapi.instancemethod(id)
    testfunction = _testcapi.instancemethod(testfunction)

class CAPITest(unittest.TestCase):

    def test_instancemethod(self):
        inst = InstanceMethod()
        self.assertEqual(id(inst), inst.id())
        self.assertTrue(inst.testfunction() is inst)
        self.assertEqual(inst.testfunction.__doc__, testfunction.__doc__)
        self.assertEqual(InstanceMethod.testfunction.__doc__, testfunction.__doc__)

        InstanceMethod.testfunction.attribute = "test"
        self.assertEqual(testfunction.attribute, "test")
        self.assertRaises(AttributeError, setattr, inst.testfunction, "attribute", "test")

    @unittest.skipUnless(threading, 'Threading required for this test.')
    def test_no_FatalError_infinite_loop(self):
        with support.SuppressCrashReport():
            p = subprocess.Popen([sys.executable, "-c",
                                  'import _testcapi;'
                                  '_testcapi.crash_no_current_thread()'],
                                 stdout=subprocess.PIPE,
                                 stderr=subprocess.PIPE)
        (out, err) = p.communicate()
        self.assertEqual(out, b'')
        # This used to cause an infinite loop.
        self.assertTrue(err.rstrip().startswith(
                         b'Fatal Python error:'
                         b' PyThreadState_Get: no current thread'))

    def test_memoryview_from_NULL_pointer(self):
        self.assertRaises(ValueError, _testcapi.make_memoryview_from_NULL_pointer)

    def test_exc_info(self):
        raised_exception = ValueError("5")
        new_exc = TypeError("TEST")
        try:
            raise raised_exception
        except ValueError as e:
            tb = e.__traceback__
            orig_sys_exc_info = sys.exc_info()
            orig_exc_info = _testcapi.set_exc_info(new_exc.__class__, new_exc, None)
            new_sys_exc_info = sys.exc_info()
            new_exc_info = _testcapi.set_exc_info(*orig_exc_info)
            reset_sys_exc_info = sys.exc_info()

            self.assertEqual(orig_exc_info[1], e)

            self.assertSequenceEqual(orig_exc_info, (raised_exception.__class__, raised_exception, tb))
            self.assertSequenceEqual(orig_sys_exc_info, orig_exc_info)
            self.assertSequenceEqual(reset_sys_exc_info, orig_exc_info)
            self.assertSequenceEqual(new_exc_info, (new_exc.__class__, new_exc, None))
            self.assertSequenceEqual(new_sys_exc_info, new_exc_info)
        else:
            self.assertTrue(False)

    @unittest.skipUnless(_posixsubprocess, '_posixsubprocess required for this test.')
    def test_seq_bytes_to_charp_array(self):
        # Issue #15732: crash in _PySequence_BytesToCharpArray()
        class Z(object):
            def __len__(self):
                return 1
        self.assertRaises(TypeError, _posixsubprocess.fork_exec,
                          1,Z(),3,[1, 2],5,6,7,8,9,10,11,12,13,14,15,16,17)
        # Issue #15736: overflow in _PySequence_BytesToCharpArray()
        class Z(object):
            def __len__(self):
                return sys.maxsize
            def __getitem__(self, i):
                return b'x'
        self.assertRaises(MemoryError, _posixsubprocess.fork_exec,
                          1,Z(),3,[1, 2],5,6,7,8,9,10,11,12,13,14,15,16,17)

    @unittest.skipUnless(_posixsubprocess, '_posixsubprocess required for this test.')
    def test_subprocess_fork_exec(self):
        class Z(object):
            def __len__(self):
                return 1

        # Issue #15738: crash in subprocess_fork_exec()
        self.assertRaises(TypeError, _posixsubprocess.fork_exec,
                          Z(),[b'1'],3,[1, 2],5,6,7,8,9,10,11,12,13,14,15,16,17)

@unittest.skipUnless(threading, 'Threading required for this test.')
class TestPendingCalls(unittest.TestCase):

    def pendingcalls_submit(self, l, n):
        def callback():
            #this function can be interrupted by thread switching so let's
            #use an atomic operation
            l.append(None)

        for i in range(n):
            time.sleep(random.random()*0.02) #0.01 secs on average
            #try submitting callback until successful.
            #rely on regular interrupt to flush queue if we are
            #unsuccessful.
            while True:
                if _testcapi._pending_threadfunc(callback):
                    break;

    def pendingcalls_wait(self, l, n, context = None):
        #now, stick around until l[0] has grown to 10
        count = 0;
        while len(l) != n:
            #this busy loop is where we expect to be interrupted to
            #run our callbacks.  Note that callbacks are only run on the
            #main thread
            if False and support.verbose:
                print("(%i)"%(len(l),),)
            for i in range(1000):
                a = i*i
            if context and not context.event.is_set():
                continue
            count += 1
            self.assertTrue(count < 10000,
                "timeout waiting for %i callbacks, got %i"%(n, len(l)))
        if False and support.verbose:
            print("(%i)"%(len(l),))

    def test_pendingcalls_threaded(self):

        #do every callback on a separate thread
        n = 32 #total callbacks
        threads = []
        class foo(object):pass
        context = foo()
        context.l = []
        context.n = 2 #submits per thread
        context.nThreads = n // context.n
        context.nFinished = 0
        context.lock = threading.Lock()
        context.event = threading.Event()

        for i in range(context.nThreads):
            t = threading.Thread(target=self.pendingcalls_thread, args = (context,))
            t.start()
            threads.append(t)

        self.pendingcalls_wait(context.l, n, context)

        for t in threads:
            t.join()

    def pendingcalls_thread(self, context):
        try:
            self.pendingcalls_submit(context.l, context.n)
        finally:
            with context.lock:
                context.nFinished += 1
                nFinished = context.nFinished
                if False and support.verbose:
                    print("finished threads: ", nFinished)
            if nFinished == context.nThreads:
                context.event.set()

    def test_pendingcalls_non_threaded(self):
        #again, just using the main thread, likely they will all be dispatched at
        #once.  It is ok to ask for too many, because we loop until we find a slot.
        #the loop can be interrupted to dispatch.
        #there are only 32 dispatch slots, so we go for twice that!
        l = []
        n = 64
        self.pendingcalls_submit(l, n)
        self.pendingcalls_wait(l, n)


class SubinterpreterTest(unittest.TestCase):

    def test_subinterps(self):
        import builtins
        r, w = os.pipe()
        code = """if 1:
            import sys, builtins, pickle
            with open({:d}, "wb") as f:
                pickle.dump(id(sys.modules), f)
                pickle.dump(id(builtins), f)
            """.format(w)
        with open(r, "rb") as f:
            ret = _testcapi.run_in_subinterp(code)
            self.assertEqual(ret, 0)
            self.assertNotEqual(pickle.load(f), id(sys.modules))
            self.assertNotEqual(pickle.load(f), id(builtins))


# Bug #6012
class Test6012(unittest.TestCase):
    def test(self):
        self.assertEqual(_testcapi.argparsing("Hello", "World"), 1)


class EmbeddingTests(unittest.TestCase):
    def setUp(self):
        basepath = os.path.dirname(os.path.dirname(os.path.dirname(__file__)))
        exename = "_testembed"
        if sys.platform.startswith("win"):
            ext = ("_d" if "_d" in sys.executable else "") + ".exe"
            exename += ext
            exepath = os.path.dirname(sys.executable)
        else:
            exepath = os.path.join(basepath, "Modules")
        self.test_exe = exe = os.path.join(exepath, exename)
        if not os.path.exists(exe):
            self.skipTest("%r doesn't exist" % exe)
        # This is needed otherwise we get a fatal error:
        # "Py_Initialize: Unable to get the locale encoding
        # LookupError: no codec search functions registered: can't find encoding"
        self.oldcwd = os.getcwd()
        os.chdir(basepath)

    def tearDown(self):
        os.chdir(self.oldcwd)

    def run_embedded_interpreter(self, *args):
        """Runs a test in the embedded interpreter"""
        cmd = [self.test_exe]
        cmd.extend(args)
        p = subprocess.Popen(cmd,
                             stdout=subprocess.PIPE,
                             stderr=subprocess.PIPE)
        (out, err) = p.communicate()
        self.assertEqual(p.returncode, 0,
                         "bad returncode %d, stderr is %r" %
                         (p.returncode, err))
        return out.decode("latin1"), err.decode("latin1")

    def test_subinterps(self):
        # This is just a "don't crash" test
        out, err = self.run_embedded_interpreter()
        if support.verbose:
            print()
            print(out)
            print(err)

    @staticmethod
    def _get_default_pipe_encoding():
        rp, wp = os.pipe()
        try:
            with os.fdopen(wp, 'w') as w:
                default_pipe_encoding = w.encoding
        finally:
            os.close(rp)
        return default_pipe_encoding

    def test_forced_io_encoding(self):
        # Checks forced configuration of embedded interpreter IO streams
        out, err = self.run_embedded_interpreter("forced_io_encoding")
        if support.verbose:
            print()
            print(out)
            print(err)
        expected_stdin_encoding = sys.__stdin__.encoding
        expected_pipe_encoding = self._get_default_pipe_encoding()
        expected_output = os.linesep.join([
        "--- Use defaults ---",
        "Expected encoding: default",
        "Expected errors: default",
        "stdin: {0}:strict",
        "stdout: {1}:strict",
        "stderr: {1}:backslashreplace",
        "--- Set errors only ---",
        "Expected encoding: default",
        "Expected errors: surrogateescape",
        "stdin: {0}:surrogateescape",
        "stdout: {1}:surrogateescape",
        "stderr: {1}:backslashreplace",
        "--- Set encoding only ---",
        "Expected encoding: latin-1",
        "Expected errors: default",
        "stdin: latin-1:strict",
        "stdout: latin-1:strict",
        "stderr: latin-1:backslashreplace",
        "--- Set encoding and errors ---",
        "Expected encoding: latin-1",
        "Expected errors: surrogateescape",
        "stdin: latin-1:surrogateescape",
        "stdout: latin-1:surrogateescape",
        "stderr: latin-1:backslashreplace"]).format(expected_stdin_encoding,
                                                    expected_pipe_encoding)
        # This is useful if we ever trip over odd platform behaviour
        self.maxDiff = None
        self.assertEqual(out.strip(), expected_output)

class SkipitemTest(unittest.TestCase):

    def test_skipitem(self):
        """
        If this test failed, you probably added a new "format unit"
        in Python/getargs.c, but neglected to update our poor friend
        skipitem() in the same file.  (If so, shame on you!)

        With a few exceptions**, this function brute-force tests all
        printable ASCII*** characters (32 to 126 inclusive) as format units,
        checking to see that PyArg_ParseTupleAndKeywords() return consistent
        errors both when the unit is attempted to be used and when it is
        skipped.  If the format unit doesn't exist, we'll get one of two
        specific error messages (one for used, one for skipped); if it does
        exist we *won't* get that error--we'll get either no error or some
        other error.  If we get the specific "does not exist" error for one
        test and not for the other, there's a mismatch, and the test fails.

           ** Some format units have special funny semantics and it would
              be difficult to accomodate them here.  Since these are all
              well-established and properly skipped in skipitem() we can
              get away with not testing them--this test is really intended
              to catch *new* format units.

          *** Python C source files must be ASCII.  Therefore it's impossible
              to have non-ASCII format units.

        """
        empty_tuple = ()
        tuple_1 = (0,)
        dict_b = {'b':1}
        keywords = ["a", "b"]

        for i in range(32, 127):
            c = chr(i)

            # skip parentheses, the error reporting is inconsistent about them
            # skip 'e', it's always a two-character code
            # skip '|' and '$', they don't represent arguments anyway
            if c in '()e|$':
                continue

            # test the format unit when not skipped
            format = c + "i"
            try:
                # (note: the format string must be bytes!)
                _testcapi.parse_tuple_and_keywords(tuple_1, dict_b,
                    format.encode("ascii"), keywords)
                when_not_skipped = False
            except TypeError as e:
                s = "argument 1 must be impossible<bad format char>, not int"
                when_not_skipped = (str(e) == s)
            except RuntimeError as e:
                when_not_skipped = False

            # test the format unit when skipped
            optional_format = "|" + format
            try:
                _testcapi.parse_tuple_and_keywords(empty_tuple, dict_b,
                    optional_format.encode("ascii"), keywords)
                when_skipped = False
            except RuntimeError as e:
                s = "impossible<bad format char>: '{}'".format(format)
                when_skipped = (str(e) == s)

            message = ("test_skipitem_parity: "
                "detected mismatch between convertsimple and skipitem "
                "for format unit '{}' ({}), not skipped {}, skipped {}".format(
                    c, i, when_skipped, when_not_skipped))
            self.assertIs(when_skipped, when_not_skipped, message)

    def test_parse_tuple_and_keywords(self):
        # parse_tuple_and_keywords error handling tests
        self.assertRaises(TypeError, _testcapi.parse_tuple_and_keywords,
                          (), {}, 42, [])
        self.assertRaises(ValueError, _testcapi.parse_tuple_and_keywords,
                          (), {}, b'', 42)
        self.assertRaises(ValueError, _testcapi.parse_tuple_and_keywords,
                          (), {}, b'', [''] * 42)
        self.assertRaises(ValueError, _testcapi.parse_tuple_and_keywords,
                          (), {}, b'', [42])

@unittest.skipUnless(threading, 'Threading required for this test.')
class TestThreadState(unittest.TestCase):

    @support.reap_threads
    def test_thread_state(self):
        # some extra thread-state tests driven via _testcapi
        def target():
            idents = []

            def callback():
                idents.append(threading.get_ident())

            _testcapi._test_thread_state(callback)
            a = b = callback
            time.sleep(1)
            # Check our main thread is in the list exactly 3 times.
            self.assertEqual(idents.count(threading.get_ident()), 3,
                             "Couldn't find main thread correctly in the list")

        target()
        t = threading.Thread(target=target)
        t.start()
        t.join()

class Test_testcapi(unittest.TestCase):
    def test__testcapi(self):
        for name in dir(_testcapi):
            if name.startswith('test_'):
                with self.subTest("internal", name=name):
                    test = getattr(_testcapi, name)
                    test()

if __name__ == "__main__":
    unittest.main()