Test functools.singledispatch/functools.singledispatchmethod annotate functions

Author: dr-carlos

Lib/test/test_annotationlib.py

@@ -1719,6 +1719,75 @@ def format(format, /, __Format=Format,
 
         self.assertEqual(annotations, {"x": int, "y": str})
 
+    def test_callable_singledispatch_annotate_forwardref_value_fallback(self):
+        # If Format.STRING and Format.VALUE_WITH_FAKE_GLOBALS are not
+        # supported fall back to Format.VALUE and convert to strings
+        @functools.singledispatch
+        def format(format, /, __Format=Format,
+                   __NotImplementedError=NotImplementedError):
+            if format == __Format.VALUE:
+                return {"x": str}
+            else:
+                raise __NotImplementedError(format)
+
+        @format.register(float)
+        def _(format, /, __Format=Format,
+                   __NotImplementedError=NotImplementedError):
+            if format == __Format.VALUE:
+                return {"x": float}
+            else:
+                raise __NotImplementedError(format)
+
+        @format.register(int)
+        def _(format, /, __Format=Format,
+              __NotImplementedError=NotImplementedError):
+            if format == __Format.VALUE:
+                return {"x": int}
+            else:
+                raise __NotImplementedError(format)
+
+        annotations = annotationlib.call_annotate_function(
+            format,
+            Format.FORWARDREF,
+        )
+
+        self.assertEqual(annotations, {"x": int})
+
+    def test_callable_singledispatchmethod_annotate_forwardref_value_fallback(self):
+        # If Format.STRING and Format.VALUE_WITH_FAKE_GLOBALS are not
+        # supported fall back to Format.VALUE and convert to strings
+        class Annotate:
+            @functools.singledispatchmethod
+            def format(self, format, /, __Format=Format,
+                       __NotImplementedError=NotImplementedError):
+                if format == __Format.VALUE:
+                    return {"x": str}
+                else:
+                    raise __NotImplementedError(format)
+
+            @format.register(float)
+            def _(self, format, /, __Format=Format,
+                  __NotImplementedError=NotImplementedError):
+                if format == __Format.VALUE:
+                    return {"x": float}
+                else:
+                    raise __NotImplementedError(format)
+
+            @format.register(int)
+            def _(self, format, /, __Format=Format,
+                  __NotImplementedError=NotImplementedError):
+                if format == __Format.VALUE:
+                    return {"x": int}
+                else:
+                    raise __NotImplementedError(format)
+
+        annotations = annotationlib.call_annotate_function(
+            Annotate().format,
+            Format.FORWARDREF,
+        )
+
+        self.assertEqual(annotations, {"x": int})
+
     def test_callable_object_annotate_string_fakeglobals(self):
         # If Format.STRING is not supported but Format.VALUE_WITH_FAKE_GLOBALS is
         # prefer that over Format.VALUE