From 7f4c8121db62a9f72f00f2d9f73381e82f289581 Mon Sep 17 00:00:00 2001
From: "Erlend E. Aasland" <erlend@python.org>
Date: Mon, 3 Jul 2023 22:16:50 +0200
Subject: [PATCH] gh-106368: Increase Argument Clinic test coverage (#106369)

Add tests for 'self' and 'defining_class' converter requirements.
---
 Lib/test/test_clinic.py | 57 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 57 insertions(+)

diff --git a/Lib/test/test_clinic.py b/Lib/test/test_clinic.py
index fab2d2bb0bd..51d2ac97275 100644
--- a/Lib/test/test_clinic.py
+++ b/Lib/test/test_clinic.py
@@ -829,6 +829,63 @@ Annotations must be either a name, a function call, or a string.
                 out = self.parse_function_should_fail(fn)
                 self.assertEqual(out, expected_error_msg)
 
+    def test_self_param_placement(self):
+        expected_error_msg = (
+            "Error on line 0:\n"
+            "A 'self' parameter, if specified, must be the very first thing "
+            "in the parameter block.\n"
+        )
+        block = """
+            module foo
+            foo.func
+                a: int
+                self: self(type="PyObject *")
+        """
+        out = self.parse_function_should_fail(block)
+        self.assertEqual(out, expected_error_msg)
+
+    def test_self_param_cannot_be_optional(self):
+        expected_error_msg = (
+            "Error on line 0:\n"
+            "A 'self' parameter cannot be marked optional.\n"
+        )
+        block = """
+            module foo
+            foo.func
+                self: self(type="PyObject *") = None
+        """
+        out = self.parse_function_should_fail(block)
+        self.assertEqual(out, expected_error_msg)
+
+    def test_defining_class_param_placement(self):
+        expected_error_msg = (
+            "Error on line 0:\n"
+            "A 'defining_class' parameter, if specified, must either be the "
+            "first thing in the parameter block, or come just after 'self'.\n"
+        )
+        block = """
+            module foo
+            foo.func
+                self: self(type="PyObject *")
+                a: int
+                cls: defining_class
+        """
+        out = self.parse_function_should_fail(block)
+        self.assertEqual(out, expected_error_msg)
+
+    def test_defining_class_param_cannot_be_optional(self):
+        expected_error_msg = (
+            "Error on line 0:\n"
+            "A 'defining_class' parameter cannot be marked optional.\n"
+        )
+        block = """
+            module foo
+            foo.func
+                cls: defining_class(type="PyObject *") = None
+        """
+        out = self.parse_function_should_fail(block)
+        self.assertEqual(out, expected_error_msg)
+
     def test_unused_param(self):
         block = self.parse("""
             module foo