[3.11] pythongh-106368: Increase Argument Clinic test coverage (python#106369)

Add tests for 'self' and 'defining_class' converter requirements.
(cherry picked from commit 7f4c812)

Co-authored-by: Erlend E. Aasland <[email protected]>

Author: erlend-aasland

Lib/test/test_clinic.py

@@ -812,6 +812,117 @@ def test_other_bizarre_things_in_annotations_fail(self):
         )
         self.assertEqual(s, expected_failure_message)
 
+    def test_kwarg_splats_disallowed_in_function_call_annotations(self):
+        expected_error_msg = (
+            "Error on line 0:\n"
+            "Cannot use a kwarg splat in a function-call annotation\n"
+        )
+        dataset = (
+            'module fo\nfo.barbaz\n   o: bool(**{None: "bang!"})',
+            'module fo\nfo.barbaz -> bool(**{None: "bang!"})',
+            'module fo\nfo.barbaz -> bool(**{"bang": 42})',
+            'module fo\nfo.barbaz\n   o: bool(**{"bang": None})',
+        )
+        for fn in dataset:
+            with self.subTest(fn=fn):
+                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
+            foo.func
+                fn: object
+                k: float
+                i: float(unused=True)
+                /
+                *
+                flag: bool(unused=True) = False
+        """)
+        sig = block.signatures[1]  # Function index == 1
+        params = sig.parameters
+        conv = lambda fn: params[fn].converter
+        dataset = (
+            {"name": "fn", "unused": False},
+            {"name": "k", "unused": False},
+            {"name": "i", "unused": True},
+            {"name": "flag", "unused": True},
+        )
+        for param in dataset:
+            name, unused = param.values()
+            with self.subTest(name=name, unused=unused):
+                p = conv(name)
+                # Verify that the unused flag is parsed correctly.
+                self.assertEqual(unused, p.unused)
+
+                # Now, check that we'll produce correct code.
+                decl = p.simple_declaration(in_parser=False)
+                if unused:
+                    self.assertIn("Py_UNUSED", decl)
+                else:
+                    self.assertNotIn("Py_UNUSED", decl)
+
+                # Make sure the Py_UNUSED macro is not used in the parser body.
+                parser_decl = p.simple_declaration(in_parser=True)
+                self.assertNotIn("Py_UNUSED", parser_decl)
+
     def parse(self, text):
         c = FakeClinic()
         parser = DSLParser(c)