gh-111545: Test PyHash_GetFuncDef() function (#112098)

Add Modules/_testcapi/hash.c and Lib/test/test_capi/test_hash.py.

2 files changed, 57 insertions, 0 deletions

diff --git a/Modules/_testcapi/hash.c b/Modules/_testcapi/hash.c
new file mode 100644
index 0000000..d0b8127
--- /dev/null
+++ b/Modules/_testcapi/hash.c
@@ -0,0 +1,56 @@
+#include "parts.h"
+#include "util.h"
+
+static PyObject *
+hash_getfuncdef(PyObject *Py_UNUSED(module), PyObject *Py_UNUSED(args))
+{
+    // bind PyHash_GetFuncDef()
+    PyHash_FuncDef *def = PyHash_GetFuncDef();
+
+    PyObject *types = PyImport_ImportModule("types");
+    if (types == NULL) {
+        return NULL;
+    }
+
+    PyObject *result = PyObject_CallMethod(types, "SimpleNamespace", NULL);
+    Py_DECREF(types);
+    if (result == NULL) {
+        return NULL;
+    }
+
+    // ignore PyHash_FuncDef.hash
+
+    PyObject *value = PyUnicode_FromString(def->name);
+    int res = PyObject_SetAttrString(result, "name", value);
+    Py_DECREF(value);
+    if (res < 0) {
+        return NULL;
+    }
+
+    value = PyLong_FromLong(def->hash_bits);
+    res = PyObject_SetAttrString(result, "hash_bits", value);
+    Py_DECREF(value);
+    if (res < 0) {
+        return NULL;
+    }
+
+    value = PyLong_FromLong(def->seed_bits);
+    res = PyObject_SetAttrString(result, "seed_bits", value);
+    Py_DECREF(value);
+    if (res < 0) {
+        return NULL;
+    }
+
+    return result;
+}
+
+static PyMethodDef test_methods[] = {
+    {"hash_getfuncdef", hash_getfuncdef, METH_NOARGS},
+    {NULL},
+};
+
+int
+_PyTestCapi_Init_Hash(PyObject *m)
+{
+    return PyModule_AddFunctions(m, test_methods);
+}
diff --git a/Modules/_testcapi/parts.h b/Modules/_testcapi/parts.h
index 9af414e..29817ed 100644
--- a/Modules/_testcapi/parts.h
+++ b/Modules/_testcapi/parts.h
@@ -58,6 +58,7 @@ int _PyTestCapi_Init_Codec(PyObject *module);
 int _PyTestCapi_Init_Immortal(PyObject *module);
 int _PyTestCapi_Init_GC(PyObject *module);
 int _PyTestCapi_Init_Sys(PyObject *module);
+int _PyTestCapi_Init_Hash(PyObject *module);
 
 int _PyTestCapi_Init_VectorcallLimited(PyObject *module);
 int _PyTestCapi_Init_HeaptypeRelative(PyObject *module);