gh-111065: Add more tests for the C API with the PySys_ prefix (GH-111067)

* Move existing tests for PySys_GetObject() and PySys_SetObject() into
  specialized files.
* Add test for PySys_GetXOptions() using _testcapi.
* Add tests for PySys_FormatStdout(), PySys_FormatStderr(),
  PySys_WriteStdout() and PySys_WriteStderr() using ctypes.

2 files changed, 57 insertions, 0 deletions

diff --git a/Modules/_testcapi/parts.h b/Modules/_testcapi/parts.h
index e5dbb9c..4fa77a8 100644
--- a/Modules/_testcapi/parts.h
+++ b/Modules/_testcapi/parts.h
@@ -49,6 +49,7 @@ int _PyTestCapi_Init_PyAtomic(PyObject *module);
 int _PyTestCapi_Init_PyOS(PyObject *module);
 int _PyTestCapi_Init_Immortal(PyObject *module);
 int _PyTestCapi_Init_GC(PyObject *mod);
+int _PyTestCapi_Init_Sys(PyObject *);
 
 int _PyTestCapi_Init_VectorcallLimited(PyObject *module);
 int _PyTestCapi_Init_HeaptypeRelative(PyObject *module);
diff --git a/Modules/_testcapi/sys.c b/Modules/_testcapi/sys.c
new file mode 100644
index 0000000..aa40e3c
--- /dev/null
+++ b/Modules/_testcapi/sys.c
@@ -0,0 +1,56 @@
+#include "parts.h"
+#include "util.h"
+
+
+static PyObject *
+sys_getobject(PyObject *Py_UNUSED(module), PyObject *arg)
+{
+    const char *name;
+    Py_ssize_t size;
+    if (!PyArg_Parse(arg, "z#", &name, &size)) {
+        return NULL;
+    }
+    PyObject *result = PySys_GetObject(name);
+    if (result == NULL) {
+        result = PyExc_AttributeError;
+    }
+    return Py_NewRef(result);
+}
+
+static PyObject *
+sys_setobject(PyObject *Py_UNUSED(module), PyObject *args)
+{
+    const char *name;
+    Py_ssize_t size;
+    PyObject *value;
+    if (!PyArg_ParseTuple(args, "z#O", &name, &size, &value)) {
+        return NULL;
+    }
+    NULLABLE(value);
+    RETURN_INT(PySys_SetObject(name, value));
+}
+
+static PyObject *
+sys_getxoptions(PyObject *Py_UNUSED(module), PyObject *Py_UNUSED(ignored))
+{
+    PyObject *result = PySys_GetXOptions();
+    return Py_XNewRef(result);
+}
+
+
+static PyMethodDef test_methods[] = {
+    {"sys_getobject", sys_getobject, METH_O},
+    {"sys_setobject", sys_setobject, METH_VARARGS},
+    {"sys_getxoptions", sys_getxoptions, METH_NOARGS},
+    {NULL},
+};
+
+int
+_PyTestCapi_Init_Sys(PyObject *m)
+{
+    if (PyModule_AddFunctions(m, test_methods) < 0) {
+        return -1;
+    }
+
+    return 0;
+}