Merge pull request #191 from pradeep90/master

Render empty tuple type correctly.

monkeytype/stubs.py

@@ -342,7 +342,7 @@ def rewrite_type_variable(self, type_variable: Any) -> str:
         return rendered[len(tilde_prefix):] if rendered.startswith(tilde_prefix) else rendered
 
     def make_builtin_tuple(self, elements: Iterable[str]) -> str:
-        return ', '.join(elements)
+        return ', '.join(elements) if elements else '()'
 
     def make_container_type(self, container_type: str, elements: str) -> str:
         return f'{container_type}[{elements}]'

tests/test_stubs.py

@@ -205,6 +205,7 @@ class TestRenderAnnotation:
             (List[Generator[make_forward_ref('Foo'), None, None]], 'List[Generator[\'Foo\', None, None]]'),
             (T, 'T'),
             (Dict[str, T], 'Dict[str, T]'),
+            (Tuple[()], 'Tuple[()]'),
         ],
     )
     def test_render_annotation(self, annotation, expected):
@@ -755,6 +756,30 @@ def test_render_typed_dict_base_and_subclass(self):
             '    def an_instance_method(self, foo: \'FooTypedDict__RENAME_ME__NonTotal\', bar: int) -> int: ...'])
         assert build_module_stubs(entries)['tests.util'].render() == expected
 
+    def test_render_return_empty_tuple(self):
+        """Regression test for #190."""
+        function = FunctionDefinition.from_callable_and_traced_types(
+            Dummy.an_instance_method,
+            {
+                'foo': int,
+                'bar': int,
+            },
+            Tuple[()],
+            yield_type=None,
+            existing_annotation_strategy=ExistingAnnotationStrategy.IGNORE
+        )
+        entries = [function]
+        expected = '\n'.join([
+            'from typing import Tuple',
+            '',
+            '',
+            'class Dummy:',
+            '    def an_instance_method(self, foo: int, bar: int)'
+            ' -> Tuple[()]: ...',
+        ])
+        self.maxDiff = None
+        assert build_module_stubs(entries)['tests.util'].render() == expected
+
 
 class TestBuildModuleStubs:
     def test_build_module_stubs(self):

tests/test_typing.py

@@ -528,6 +528,7 @@ class TestGetType:
             ('foo', str),
             (Dummy, Type[Dummy]),
             (1.1, float),
+            ((), typing_Tuple[()]),
             (('a', 1, True), typing_Tuple[str, int, bool]),
             (set(), Set[Any]),
             ({'a', 'b', 'c'}, Set[str]),