GH-94808: Cover `PyOS_mystrnicmp` and `PyOS_mystricmp` (gh-102469)

2 files changed, 61 insertions, 0 deletions

diff --git a/Modules/_testcapi/parts.h b/Modules/_testcapi/parts.h
index c8f31dc..60ec81d 100644
--- a/Modules/_testcapi/parts.h
+++ b/Modules/_testcapi/parts.h
@@ -38,6 +38,7 @@ int _PyTestCapi_Init_Float(PyObject *module);
 int _PyTestCapi_Init_Structmember(PyObject *module);
 int _PyTestCapi_Init_Exceptions(PyObject *module);
 int _PyTestCapi_Init_Code(PyObject *module);
+int _PyTestCapi_Init_PyOS(PyObject *module);
 
 #ifdef LIMITED_API_AVAILABLE
 int _PyTestCapi_Init_VectorcallLimited(PyObject *module);
diff --git a/Modules/_testcapi/pyos.c b/Modules/_testcapi/pyos.c
new file mode 100644
index 0000000..63140e9
--- /dev/null
+++ b/Modules/_testcapi/pyos.c
@@ -0,0 +1,60 @@
+#include "parts.h"
+
+
+static PyObject *
+test_PyOS_mystrnicmp(PyObject *self, PyObject *Py_UNUSED(ignored))
+{
+    assert(PyOS_mystrnicmp("", "", 0) == 0);
+    assert(PyOS_mystrnicmp("", "", 1) == 0);
+
+    assert(PyOS_mystrnicmp("insert", "ins", 3) == 0);
+    assert(PyOS_mystrnicmp("ins", "insert", 3) == 0);
+    assert(PyOS_mystrnicmp("insect", "insert", 3) == 0);
+
+    assert(PyOS_mystrnicmp("insert", "insert", 6) == 0);
+    assert(PyOS_mystrnicmp("Insert", "insert", 6) == 0);
+    assert(PyOS_mystrnicmp("INSERT", "insert", 6) == 0);
+    assert(PyOS_mystrnicmp("insert", "insert", 10) == 0);
+
+    assert(PyOS_mystrnicmp("invert", "insert", 6) == ('v' - 's'));
+    assert(PyOS_mystrnicmp("insert", "invert", 6) == ('s' - 'v'));
+    assert(PyOS_mystrnicmp("insert", "ins\0rt", 6) == 'e');
+
+    // GH-21845
+    assert(PyOS_mystrnicmp("insert\0a", "insert\0b", 8) == 0);
+
+    Py_RETURN_NONE;
+}
+
+static PyObject *
+test_PyOS_mystricmp(PyObject *self, PyObject *Py_UNUSED(ignored))
+{
+    assert(PyOS_mystricmp("", "") == 0);
+    assert(PyOS_mystricmp("insert", "insert") == 0);
+    assert(PyOS_mystricmp("Insert", "insert") == 0);
+    assert(PyOS_mystricmp("INSERT", "insert") == 0);
+    assert(PyOS_mystricmp("insert", "ins") == 'e');
+    assert(PyOS_mystricmp("ins", "insert") == -'e');
+
+    // GH-21845
+    assert(PyOS_mystricmp("insert", "ins\0rt") == 'e');
+    assert(PyOS_mystricmp("invert", "insert") == ('v' - 's'));
+
+    Py_RETURN_NONE;
+}
+
+static PyMethodDef test_methods[] = {
+    {"test_PyOS_mystrnicmp", test_PyOS_mystrnicmp, METH_NOARGS, NULL},
+    {"test_PyOS_mystricmp", test_PyOS_mystricmp, METH_NOARGS, NULL},
+    {NULL},
+};
+
+int
+_PyTestCapi_Init_PyOS(PyObject *mod)
+{
+    if (PyModule_AddFunctions(mod, test_methods) < 0) {
+        return -1;
+    }
+
+    return 0;
+}