_testcapimodule.c

/*
 * C Extension module to test Python interpreter C APIs.
 *
 * The 'test_*' functions exported by this module are run as part of the
 * standard Python regression test, via Lib/test/test_capi.py.
 */

/* This module tests the public (Include/ and Include/cpython/) C API.
   The internal C API must not be used here: use _testinternalcapi for that.

   The Visual Studio projects builds _testcapi with Py_BUILD_CORE_MODULE
   macro defined, but only the public C API must be tested here. */

#undef Py_BUILD_CORE_MODULE
#undef Py_BUILD_CORE_BUILTIN

/* Always enable assertions */
#undef NDEBUG

#define PY_SSIZE_T_CLEAN

#include "Python.h"
#include "frameobject.h"          // PyFrame_New
#include "marshal.h"              // PyMarshal_WriteLongToFile
#include "structmember.h"         // for offsetof(), T_OBJECT
#include <float.h>                // FLT_MAX
#include <signal.h>
#ifndef MS_WINDOWS
#include <unistd.h>
#endif

#ifdef HAVE_SYS_WAIT_H
#include <sys/wait.h>             // W_STOPCODE
#endif

#ifdef Py_BUILD_CORE
#  error "_testcapi must test the public Python C API, not CPython internal C API"
#endif

#ifdef bool
#  error "The public headers should not include <stdbool.h>, see bpo-46748"
#endif

// Several parts of this module are broken out into files in _testcapi/.
// Include definitions from there.
#include "_testcapi/parts.h"

// Forward declarations
static struct PyModuleDef _testcapimodule;
static PyObject *TestError;     /* set to exception object in init */


/* Raise TestError with test_name + ": " + msg, and return NULL. */

static PyObject *
raiseTestError(const char* test_name, const char* msg)
{
    PyErr_Format(TestError, "%s: %s", test_name, msg);
    return NULL;
}

/* Test #defines from pyconfig.h (particularly the SIZEOF_* defines).

   The ones derived from autoconf on the UNIX-like OSes can be relied
   upon (in the absence of sloppy cross-compiling), but the Windows
   platforms have these hardcoded.  Better safe than sorry.
*/
static PyObject*
sizeof_error(const char* fatname, const char* typname,
    int expected, int got)
{
    PyErr_Format(TestError,
        "%s #define == %d but sizeof(%s) == %d",
        fatname, expected, typname, got);
    return (PyObject*)NULL;
}

static PyObject*
test_config(PyObject *self, PyObject *Py_UNUSED(ignored))
{
#define CHECK_SIZEOF(FATNAME, TYPE) \
            if (FATNAME != sizeof(TYPE)) \
                return sizeof_error(#FATNAME, #TYPE, FATNAME, sizeof(TYPE))

    CHECK_SIZEOF(SIZEOF_SHORT, short);
    CHECK_SIZEOF(SIZEOF_INT, int);
    CHECK_SIZEOF(SIZEOF_LONG, long);
    CHECK_SIZEOF(SIZEOF_VOID_P, void*);
    CHECK_SIZEOF(SIZEOF_TIME_T, time_t);
    CHECK_SIZEOF(SIZEOF_LONG_LONG, long long);

#undef CHECK_SIZEOF

    Py_RETURN_NONE;
}

static PyObject*
test_sizeof_c_types(PyObject *self, PyObject *Py_UNUSED(ignored))
{
#if defined(__GNUC__) && ((__GNUC__ > 4) || ((__GNUC__ == 4) && (__GNUC_MINOR__ > 5)))
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wtype-limits"
#endif
#define CHECK_SIZEOF(TYPE, EXPECTED)         \
    if (EXPECTED != sizeof(TYPE))  {         \
        PyErr_Format(TestError,              \
            "sizeof(%s) = %u instead of %u", \
            #TYPE, sizeof(TYPE), EXPECTED);  \
        return (PyObject*)NULL;              \
    }
#define IS_SIGNED(TYPE) (((TYPE)-1) < (TYPE)0)
#define CHECK_SIGNNESS(TYPE, SIGNED)         \
    if (IS_SIGNED(TYPE) != SIGNED) {         \
        PyErr_Format(TestError,              \
            "%s signness is, instead of %i",  \
            #TYPE, IS_SIGNED(TYPE), SIGNED); \
        return (PyObject*)NULL;              \
    }

    /* integer types */
    CHECK_SIZEOF(Py_UCS1, 1);
    CHECK_SIZEOF(Py_UCS2, 2);
    CHECK_SIZEOF(Py_UCS4, 4);
    CHECK_SIGNNESS(Py_UCS1, 0);
    CHECK_SIGNNESS(Py_UCS2, 0);
    CHECK_SIGNNESS(Py_UCS4, 0);
    CHECK_SIZEOF(int32_t, 4);
    CHECK_SIGNNESS(int32_t, 1);
    CHECK_SIZEOF(uint32_t, 4);
    CHECK_SIGNNESS(uint32_t, 0);
    CHECK_SIZEOF(int64_t, 8);
    CHECK_SIGNNESS(int64_t, 1);
    CHECK_SIZEOF(uint64_t, 8);
    CHECK_SIGNNESS(uint64_t, 0);

    /* pointer/size types */
    CHECK_SIZEOF(size_t, sizeof(void *));
    CHECK_SIGNNESS(size_t, 0);
    CHECK_SIZEOF(Py_ssize_t, sizeof(void *));
    CHECK_SIGNNESS(Py_ssize_t, 1);

    CHECK_SIZEOF(uintptr_t, sizeof(void *));
    CHECK_SIGNNESS(uintptr_t, 0);
    CHECK_SIZEOF(intptr_t, sizeof(void *));
    CHECK_SIGNNESS(intptr_t, 1);

    Py_RETURN_NONE;

#undef IS_SIGNED
#undef CHECK_SIGNESS
#undef CHECK_SIZEOF
#if defined(__GNUC__) && ((__GNUC__ > 4) || ((__GNUC__ == 4) && (__GNUC_MINOR__ > 5)))
#pragma GCC diagnostic pop
#endif
}

static PyObject*
test_gc_control(PyObject *self, PyObject *Py_UNUSED(ignored))
{
    int orig_enabled = PyGC_IsEnabled();
    const char* msg = "ok";
    int old_state;

    old_state = PyGC_Enable();
    msg = "Enable(1)";
    if (old_state != orig_enabled) {
        goto failed;
    }
    msg = "IsEnabled(1)";
    if (!PyGC_IsEnabled()) {
        goto failed;
    }

    old_state = PyGC_Disable();
    msg = "disable(2)";
    if (!old_state) {
        goto failed;
    }
    msg = "IsEnabled(2)";
    if (PyGC_IsEnabled()) {
        goto failed;
    }

    old_state = PyGC_Enable();
    msg = "enable(3)";
    if (old_state) {
        goto failed;
    }
    msg = "IsEnabled(3)";
    if (!PyGC_IsEnabled()) {
        goto failed;
    }

    if (!orig_enabled) {
        old_state = PyGC_Disable();
        msg = "disable(4)";
        if (old_state) {
            goto failed;
        }
        msg = "IsEnabled(4)";
        if (PyGC_IsEnabled()) {
            goto failed;
        }
    }

    Py_RETURN_NONE;

failed:
    /* Try to clean up if we can. */
    if (orig_enabled) {
        PyGC_Enable();
    } else {
        PyGC_Disable();
    }
    PyErr_Format(TestError, "GC control failed in %s", msg);
    return NULL;
}

static PyObject*
test_list_api(PyObject *self, PyObject *Py_UNUSED(ignored))
{
    PyObject* list;
    int i;

    /* SF bug 132008:  PyList_Reverse segfaults */
#define NLIST 30
    list = PyList_New(NLIST);
    if (list == (PyObject*)NULL)
        return (PyObject*)NULL;
    /* list = range(NLIST) */
    for (i = 0; i < NLIST; ++i) {
        PyObject* anint = PyLong_FromLong(i);
        if (anint == (PyObject*)NULL) {
            Py_DECREF(list);
            return (PyObject*)NULL;
        }
        PyList_SET_ITEM(list, i, anint);
    }
    /* list.reverse(), via PyList_Reverse() */
    i = PyList_Reverse(list);   /* should not blow up! */
    if (i != 0) {
        Py_DECREF(list);
        return (PyObject*)NULL;
    }
    /* Check that list == range(29, -1, -1) now */
    for (i = 0; i < NLIST; ++i) {
        PyObject* anint = PyList_GET_ITEM(list, i);
        if (PyLong_AS_LONG(anint) != NLIST-1-i) {
            PyErr_SetString(TestError,
                            "test_list_api: reverse screwed up");
            Py_DECREF(list);
            return (PyObject*)NULL;
        }
    }
    Py_DECREF(list);
#undef NLIST

    Py_RETURN_NONE;
}

static int
test_dict_inner(int count)
{
    Py_ssize_t pos = 0, iterations = 0;
    int i;
    PyObject *dict = PyDict_New();
    PyObject *v, *k;

    if (dict == NULL)
        return -1;

    for (i = 0; i < count; i++) {
        v = PyLong_FromLong(i);
        if (v == NULL) {
            return -1;
        }
        if (PyDict_SetItem(dict, v, v) < 0) {
            Py_DECREF(v);
            return -1;
        }
        Py_DECREF(v);
    }

    while (PyDict_Next(dict, &pos, &k, &v)) {
        PyObject *o;
        iterations++;

        i = PyLong_AS_LONG(v) + 1;
        o = PyLong_FromLong(i);
        if (o == NULL)
            return -1;
        if (PyDict_SetItem(dict, k, o) < 0) {
            Py_DECREF(o);
            return -1;
        }
        Py_DECREF(o);
    }

    Py_DECREF(dict);

    if (iterations != count) {
        PyErr_SetString(
            TestError,
            "test_dict_iteration: dict iteration went wrong ");
        return -1;
    } else {
        return 0;
    }
}



static PyObject*
test_dict_iteration(PyObject* self, PyObject *Py_UNUSED(ignored))
{
    int i;

    for (i = 0; i < 200; i++) {
        if (test_dict_inner(i) < 0) {
            return NULL;
        }
    }

    Py_RETURN_NONE;
}

static PyObject*
dict_getitem_knownhash(PyObject *self, PyObject *args)
{
    PyObject *mp, *key, *result;
    Py_ssize_t hash;

    if (!PyArg_ParseTuple(args, "OOn:dict_getitem_knownhash",
                          &mp, &key, &hash)) {
        return NULL;
    }

    result = _PyDict_GetItem_KnownHash(mp, key, (Py_hash_t)hash);
    if (result == NULL && !PyErr_Occurred()) {
        _PyErr_SetKeyError(key);
        return NULL;
    }

    return Py_XNewRef(result);
}

/* Issue #4701: Check that PyObject_Hash implicitly calls
 *   PyType_Ready if it hasn't already been called
 */
static PyTypeObject _HashInheritanceTester_Type = {
    PyVarObject_HEAD_INIT(NULL, 0)
    "hashinheritancetester",            /* Name of this type */
    sizeof(PyObject),           /* Basic object size */
    0,                          /* Item size for varobject */
    (destructor)PyObject_Del, /* tp_dealloc */
    0,                          /* tp_vectorcall_offset */
    0,                          /* tp_getattr */
    0,                          /* tp_setattr */
    0,                          /* tp_as_async */
    0,                          /* tp_repr */
    0,                          /* tp_as_number */
    0,                          /* tp_as_sequence */
    0,                          /* tp_as_mapping */
    0,                          /* tp_hash */
    0,                          /* tp_call */
    0,                          /* tp_str */
    PyObject_GenericGetAttr,  /* tp_getattro */
    0,                          /* tp_setattro */
    0,                          /* tp_as_buffer */
    Py_TPFLAGS_DEFAULT,         /* tp_flags */
    0,                          /* tp_doc */
    0,                          /* tp_traverse */
    0,                          /* tp_clear */
    0,                          /* tp_richcompare */
    0,                          /* tp_weaklistoffset */
    0,                          /* tp_iter */
    0,                          /* tp_iternext */
    0,                          /* tp_methods */
    0,                          /* tp_members */
    0,                          /* tp_getset */
    0,                          /* tp_base */
    0,                          /* tp_dict */
    0,                          /* tp_descr_get */
    0,                          /* tp_descr_set */
    0,                          /* tp_dictoffset */
    0,                          /* tp_init */
    0,                          /* tp_alloc */
    PyType_GenericNew,                  /* tp_new */
};

static PyObject*
pycompilestring(PyObject* self, PyObject *obj) {
    if (PyBytes_CheckExact(obj) == 0) {
        PyErr_SetString(PyExc_ValueError, "Argument must be a bytes object");
        return NULL;
    }
    const char *the_string = PyBytes_AsString(obj);
    if (the_string == NULL) {
        return NULL;
    }
    return Py_CompileString(the_string, "<string>", Py_file_input);
}

static PyObject*
test_lazy_hash_inheritance(PyObject* self, PyObject *Py_UNUSED(ignored))
{
    PyTypeObject *type;
    PyObject *obj;
    Py_hash_t hash;

    type = &_HashInheritanceTester_Type;

    if (type->tp_dict != NULL)
        /* The type has already been initialized. This probably means
           -R is being used. */
        Py_RETURN_NONE;


    obj = PyObject_New(PyObject, type);
    if (obj == NULL) {
        PyErr_Clear();
        PyErr_SetString(
            TestError,
            "test_lazy_hash_inheritance: failed to create object");
        return NULL;
    }

    if (type->tp_dict != NULL) {
        PyErr_SetString(
            TestError,
            "test_lazy_hash_inheritance: type initialised too soon");
        Py_DECREF(obj);
        return NULL;
    }

    hash = PyObject_Hash(obj);
    if ((hash == -1) && PyErr_Occurred()) {
        PyErr_Clear();
        PyErr_SetString(
            TestError,
            "test_lazy_hash_inheritance: could not hash object");
        Py_DECREF(obj);
        return NULL;
    }

    if (type->tp_dict == NULL) {
        PyErr_SetString(
            TestError,
            "test_lazy_hash_inheritance: type not initialised by hash()");
        Py_DECREF(obj);
        return NULL;
    }

    if (type->tp_hash != PyType_Type.tp_hash) {
        PyErr_SetString(
            TestError,
            "test_lazy_hash_inheritance: unexpected hash function");
        Py_DECREF(obj);
        return NULL;
    }

    Py_DECREF(obj);

    Py_RETURN_NONE;
}

static PyObject *
return_none(void *unused)
{
    Py_RETURN_NONE;
}

static PyObject *
raise_error(void *unused)
{
    PyErr_SetNone(PyExc_ValueError);
    return NULL;
}

static int
test_buildvalue_N_error(const char *fmt)
{
    PyObject *arg, *res;

    arg = PyList_New(0);
    if (arg == NULL) {
        return -1;
    }

    Py_INCREF(arg);
    res = Py_BuildValue(fmt, return_none, NULL, arg);
    if (res == NULL) {
        return -1;
    }
    Py_DECREF(res);
    if (Py_REFCNT(arg) != 1) {
        PyErr_Format(TestError, "test_buildvalue_N: "
                     "arg was not decrefed in successful "
                     "Py_BuildValue(\"%s\")", fmt);
        return -1;
    }

    Py_INCREF(arg);
    res = Py_BuildValue(fmt, raise_error, NULL, arg);
    if (res != NULL || !PyErr_Occurred()) {
        PyErr_Format(TestError, "test_buildvalue_N: "
                     "Py_BuildValue(\"%s\") didn't complain", fmt);
        return -1;
    }
    PyErr_Clear();
    if (Py_REFCNT(arg) != 1) {
        PyErr_Format(TestError, "test_buildvalue_N: "
                     "arg was not decrefed in failed "
                     "Py_BuildValue(\"%s\")", fmt);
        return -1;
    }
    Py_DECREF(arg);
    return 0;
}

static PyObject *
test_buildvalue_N(PyObject *self, PyObject *Py_UNUSED(ignored))
{
    PyObject *arg, *res;

    arg = PyList_New(0);
    if (arg == NULL) {
        return NULL;
    }
    Py_INCREF(arg);
    res = Py_BuildValue("N", arg);
    if (res == NULL) {
        return NULL;
    }
    if (res != arg) {
        return raiseTestError("test_buildvalue_N",
                              "Py_BuildValue(\"N\") returned wrong result");
    }
    if (Py_REFCNT(arg) != 2) {
        return raiseTestError("test_buildvalue_N",
                              "arg was not decrefed in Py_BuildValue(\"N\")");
    }
    Py_DECREF(res);
    Py_DECREF(arg);

    if (test_buildvalue_N_error("O&N") < 0)
        return NULL;
    if (test_buildvalue_N_error("(O&N)") < 0)
        return NULL;
    if (test_buildvalue_N_error("[O&N]") < 0)
        return NULL;
    if (test_buildvalue_N_error("{O&N}") < 0)
        return NULL;
    if (test_buildvalue_N_error("{()O&(())N}") < 0)
        return NULL;

    Py_RETURN_NONE;
}


static PyObject *
test_get_statictype_slots(PyObject *self, PyObject *Py_UNUSED(ignored))
{
    newfunc tp_new = PyType_GetSlot(&PyLong_Type, Py_tp_new);
    if (PyLong_Type.tp_new != tp_new) {
        PyErr_SetString(PyExc_AssertionError, "mismatch: tp_new of long");
        return NULL;
    }

    reprfunc tp_repr = PyType_GetSlot(&PyLong_Type, Py_tp_repr);
    if (PyLong_Type.tp_repr != tp_repr) {
        PyErr_SetString(PyExc_AssertionError, "mismatch: tp_repr of long");
        return NULL;
    }

    ternaryfunc tp_call = PyType_GetSlot(&PyLong_Type, Py_tp_call);
    if (tp_call != NULL) {
        PyErr_SetString(PyExc_AssertionError, "mismatch: tp_call of long");
        return NULL;
    }

    binaryfunc nb_add = PyType_GetSlot(&PyLong_Type, Py_nb_add);
    if (PyLong_Type.tp_as_number->nb_add != nb_add) {
        PyErr_SetString(PyExc_AssertionError, "mismatch: nb_add of long");
        return NULL;
    }

    lenfunc mp_length = PyType_GetSlot(&PyLong_Type, Py_mp_length);
    if (mp_length != NULL) {
        PyErr_SetString(PyExc_AssertionError, "mismatch: mp_length of long");
        return NULL;
    }

    void *over_value = PyType_GetSlot(&PyLong_Type, Py_bf_releasebuffer + 1);
    if (over_value != NULL) {
        PyErr_SetString(PyExc_AssertionError, "mismatch: max+1 of long");
        return NULL;
    }

    tp_new = PyType_GetSlot(&PyLong_Type, 0);
    if (tp_new != NULL) {
        PyErr_SetString(PyExc_AssertionError, "mismatch: slot 0 of long");
        return NULL;
    }
    if (PyErr_ExceptionMatches(PyExc_SystemError)) {
        // This is the right exception
        PyErr_Clear();
    }
    else {
        return NULL;
    }

    Py_RETURN_NONE;
}


static PyType_Slot HeapTypeNameType_slots[] = {
    {0},
};

static PyType_Spec HeapTypeNameType_Spec = {
    .name = "_testcapi.HeapTypeNameType",
    .basicsize = sizeof(PyObject),
    .flags = Py_TPFLAGS_DEFAULT,
    .slots = HeapTypeNameType_slots,
};

static PyObject *
test_get_type_name(PyObject *self, PyObject *Py_UNUSED(ignored))
{
    PyObject *tp_name = PyType_GetName(&PyLong_Type);
    assert(strcmp(PyUnicode_AsUTF8(tp_name), "int") == 0);
    Py_DECREF(tp_name);

    tp_name = PyType_GetName(&PyModule_Type);
    assert(strcmp(PyUnicode_AsUTF8(tp_name), "module") == 0);
    Py_DECREF(tp_name);

    PyObject *HeapTypeNameType = PyType_FromSpec(&HeapTypeNameType_Spec);
    if (HeapTypeNameType == NULL) {
        Py_RETURN_NONE;
    }
    tp_name = PyType_GetName((PyTypeObject *)HeapTypeNameType);
    assert(strcmp(PyUnicode_AsUTF8(tp_name), "HeapTypeNameType") == 0);
    Py_DECREF(tp_name);

    PyObject *name = PyUnicode_FromString("test_name");
    if (name == NULL) {
        goto done;
    }
    if (PyObject_SetAttrString(HeapTypeNameType, "__name__", name) < 0) {
        Py_DECREF(name);
        goto done;
    }
    tp_name = PyType_GetName((PyTypeObject *)HeapTypeNameType);
    assert(strcmp(PyUnicode_AsUTF8(tp_name), "test_name") == 0);
    Py_DECREF(name);
    Py_DECREF(tp_name);

  done:
    Py_DECREF(HeapTypeNameType);
    Py_RETURN_NONE;
}


static PyObject *
test_get_type_qualname(PyObject *self, PyObject *Py_UNUSED(ignored))
{
    PyObject *tp_qualname = PyType_GetQualName(&PyLong_Type);
    assert(strcmp(PyUnicode_AsUTF8(tp_qualname), "int") == 0);
    Py_DECREF(tp_qualname);

    tp_qualname = PyType_GetQualName(&PyODict_Type);
    assert(strcmp(PyUnicode_AsUTF8(tp_qualname), "OrderedDict") == 0);
    Py_DECREF(tp_qualname);

    PyObject *HeapTypeNameType = PyType_FromSpec(&HeapTypeNameType_Spec);
    if (HeapTypeNameType == NULL) {
        Py_RETURN_NONE;
    }
    tp_qualname = PyType_GetQualName((PyTypeObject *)HeapTypeNameType);
    assert(strcmp(PyUnicode_AsUTF8(tp_qualname), "HeapTypeNameType") == 0);
    Py_DECREF(tp_qualname);

    PyObject *spec_name = PyUnicode_FromString(HeapTypeNameType_Spec.name);
    if (spec_name == NULL) {
        goto done;
    }
    if (PyObject_SetAttrString(HeapTypeNameType,
                               "__qualname__", spec_name) < 0) {
        Py_DECREF(spec_name);
        goto done;
    }
    tp_qualname = PyType_GetQualName((PyTypeObject *)HeapTypeNameType);
    assert(strcmp(PyUnicode_AsUTF8(tp_qualname),
                  "_testcapi.HeapTypeNameType") == 0);
    Py_DECREF(spec_name);
    Py_DECREF(tp_qualname);

  done:
    Py_DECREF(HeapTypeNameType);
    Py_RETURN_NONE;
}

static PyObject *
pyobject_repr_from_null(PyObject *self, PyObject *Py_UNUSED(ignored))
{
    return PyObject_Repr(NULL);
}

static PyObject *
pyobject_str_from_null(PyObject *self, PyObject *Py_UNUSED(ignored))
{
    return PyObject_Str(NULL);
}

static PyObject *
pyobject_bytes_from_null(PyObject *self, PyObject *Py_UNUSED(ignored))
{
    return PyObject_Bytes(NULL);
}

static PyObject *
set_errno(PyObject *self, PyObject *args)
{
    int new_errno;

    if (!PyArg_ParseTuple(args, "i:set_errno", &new_errno))
        return NULL;

    errno = new_errno;
    Py_RETURN_NONE;
}

/* test_thread_state spawns a thread of its own, and that thread releases
 * `thread_done` when it's finished.  The driver code has to know when the
 * thread finishes, because the thread uses a PyObject (the callable) that
 * may go away when the driver finishes.  The former lack of this explicit
 * synchronization caused rare segfaults, so rare that they were seen only
 * on a Mac buildbot (although they were possible on any box).
 */
static PyThread_type_lock thread_done = NULL;

static int
_make_call(void *callable)
{
    PyObject *rc;
    int success;
    PyGILState_STATE s = PyGILState_Ensure();
    rc = PyObject_CallNoArgs((PyObject *)callable);
    success = (rc != NULL);
    Py_XDECREF(rc);
    PyGILState_Release(s);
    return success;
}

/* Same thing, but releases `thread_done` when it returns.  This variant
 * should be called only from threads spawned by test_thread_state().
 */
static void
_make_call_from_thread(void *callable)
{
    _make_call(callable);
    PyThread_release_lock(thread_done);
}

static PyObject *
test_thread_state(PyObject *self, PyObject *args)
{
    PyObject *fn;
    int success = 1;

    if (!PyArg_ParseTuple(args, "O:test_thread_state", &fn))
        return NULL;

    if (!PyCallable_Check(fn)) {
        PyErr_Format(PyExc_TypeError, "'%s' object is not callable",
            Py_TYPE(fn)->tp_name);
        return NULL;
    }

    thread_done = PyThread_allocate_lock();
    if (thread_done == NULL)
        return PyErr_NoMemory();
    PyThread_acquire_lock(thread_done, 1);

    /* Start a new thread with our callback. */
    PyThread_start_new_thread(_make_call_from_thread, fn);
    /* Make the callback with the thread lock held by this thread */
    success &= _make_call(fn);
    /* Do it all again, but this time with the thread-lock released */
    Py_BEGIN_ALLOW_THREADS
    success &= _make_call(fn);
    PyThread_acquire_lock(thread_done, 1);  /* wait for thread to finish */
    Py_END_ALLOW_THREADS

    /* And once more with and without a thread
       XXX - should use a lock and work out exactly what we are trying
       to test <wink>
    */
    Py_BEGIN_ALLOW_THREADS
    PyThread_start_new_thread(_make_call_from_thread, fn);
    success &= _make_call(fn);
    PyThread_acquire_lock(thread_done, 1);  /* wait for thread to finish */
    Py_END_ALLOW_THREADS

    /* Release lock we acquired above.  This is required on HP-UX. */
    PyThread_release_lock(thread_done);

    PyThread_free_lock(thread_done);
    if (!success)
        return NULL;
    Py_RETURN_NONE;
}

#ifndef MS_WINDOWS
static PyThread_type_lock wait_done = NULL;

static void wait_for_lock(void *unused) {
    PyThread_acquire_lock(wait_done, 1);
    PyThread_release_lock(wait_done);
    PyThread_free_lock(wait_done);
    wait_done = NULL;
}

// These can be used to test things that care about the existence of another
// thread that the threading module doesn't know about.

static PyObject *
spawn_pthread_waiter(PyObject *self, PyObject *Py_UNUSED(ignored))
{
    if (wait_done) {
        PyErr_SetString(PyExc_RuntimeError, "thread already running");
        return NULL;
    }
    wait_done = PyThread_allocate_lock();
    if (wait_done == NULL)
        return PyErr_NoMemory();
    PyThread_acquire_lock(wait_done, 1);
    PyThread_start_new_thread(wait_for_lock, NULL);
    Py_RETURN_NONE;
}

static PyObject *
end_spawned_pthread(PyObject *self, PyObject *Py_UNUSED(ignored))
{
    if (!wait_done) {
        PyErr_SetString(PyExc_RuntimeError, "call _spawn_pthread_waiter 1st");
        return NULL;
    }
    PyThread_release_lock(wait_done);
    Py_RETURN_NONE;
}
#endif  // not MS_WINDOWS

/* test Py_AddPendingCalls using threads */
static int _pending_callback(void *arg)
{
    /* we assume the argument is callable object to which we own a reference */
    PyObject *callable = (PyObject *)arg;
    PyObject *r = PyObject_CallNoArgs(callable);
    Py_DECREF(callable);
    Py_XDECREF(r);
    return r != NULL ? 0 : -1;
}

/* The following requests n callbacks to _pending_callback.  It can be
 * run from any python thread.
 */
static PyObject *
pending_threadfunc(PyObject *self, PyObject *arg)
{
    PyObject *callable;
    int r;
    if (PyArg_ParseTuple(arg, "O", &callable) == 0)
        return NULL;

    /* create the reference for the callbackwhile we hold the lock */
    Py_INCREF(callable);

    Py_BEGIN_ALLOW_THREADS
    r = Py_AddPendingCall(&_pending_callback, callable);
    Py_END_ALLOW_THREADS

    if (r<0) {
        Py_DECREF(callable); /* unsuccessful add, destroy the extra reference */
        Py_RETURN_FALSE;
    }
    Py_RETURN_TRUE;
}

/* Test PyOS_string_to_double. */
static PyObject *
test_string_to_double(PyObject *self, PyObject *Py_UNUSED(ignored)) {
    double result;
    const char *msg;

#define CHECK_STRING(STR, expected)                             \
    result = PyOS_string_to_double(STR, NULL, NULL);            \
    if (result == -1.0 && PyErr_Occurred())                     \
        return NULL;                                            \
    if (result != (double)expected) {                           \
        msg = "conversion of " STR " to float failed";          \
        goto fail;                                              \
    }

#define CHECK_INVALID(STR)                                              \
    result = PyOS_string_to_double(STR, NULL, NULL);                    \
    if (result == -1.0 && PyErr_Occurred()) {                           \
        if (PyErr_ExceptionMatches(PyExc_ValueError))                   \
            PyErr_Clear();                                              \
        else                                                            \
            return NULL;                                                \
    }                                                                   \
    else {                                                              \
        msg = "conversion of " STR " didn't raise ValueError";          \
        goto fail;                                                      \
    }

    CHECK_STRING("0.1", 0.1);
    CHECK_STRING("1.234", 1.234);
    CHECK_STRING("-1.35", -1.35);
    CHECK_STRING(".1e01", 1.0);
    CHECK_STRING("2.e-2", 0.02);

    CHECK_INVALID(" 0.1");
    CHECK_INVALID("\t\n-3");
    CHECK_INVALID(".123 ");
    CHECK_INVALID("3\n");
    CHECK_INVALID("123abc");

    Py_RETURN_NONE;
  fail:
    return raiseTestError("test_string_to_double", msg);
#undef CHECK_STRING
#undef CHECK_INVALID
}


/* Coverage testing of capsule objects. */

static const char *capsule_name = "capsule name";
static       char *capsule_pointer = "capsule pointer";
static       char *capsule_context = "capsule context";
static const char *capsule_error = NULL;
static int
capsule_destructor_call_count = 0;

static void
capsule_destructor(PyObject *o) {
    capsule_destructor_call_count++;
    if (PyCapsule_GetContext(o) != capsule_context) {
        capsule_error = "context did not match in destructor!";
    } else if (PyCapsule_GetDestructor(o) != capsule_destructor) {
        capsule_error = "destructor did not match in destructor!  (woah!)";
    } else if (PyCapsule_GetName(o) != capsule_name) {
        capsule_error = "name did not match in destructor!";
    } else if (PyCapsule_GetPointer(o, capsule_name) != capsule_pointer) {
        capsule_error = "pointer did not match in destructor!";
    }
}

typedef struct {
    char *name;
    char *module;
    char *attribute;
} known_capsule;

static PyObject *
test_capsule(PyObject *self, PyObject *Py_UNUSED(ignored))
{
    PyObject *object;
    const char *error = NULL;
    void *pointer;
    void *pointer2;
    known_capsule known_capsules[] = {
        #define KNOWN_CAPSULE(module, name)             { module "." name, module, name }
        KNOWN_CAPSULE("_socket", "CAPI"),
        KNOWN_CAPSULE("_curses", "_C_API"),
        KNOWN_CAPSULE("datetime", "datetime_CAPI"),
        { NULL, NULL },
    };
    known_capsule *known = &known_capsules[0];

#define FAIL(x) { error = (x); goto exit; }

#define CHECK_DESTRUCTOR \
    if (capsule_error) { \
        FAIL(capsule_error); \
    } \
    else if (!capsule_destructor_call_count) {          \
        FAIL("destructor not called!"); \
    } \
    capsule_destructor_call_count = 0; \

    object = PyCapsule_New(capsule_pointer, capsule_name, capsule_destructor);
    PyCapsule_SetContext(object, capsule_context);
    capsule_destructor(object);
    CHECK_DESTRUCTOR;
    Py_DECREF(object);