Test infer_annotation

test/test_api/test_signatures.py

@@ -0,0 +1,21 @@
+import pytest
+
+
+@pytest.mark.parametrize(
+    'code, expected_params', [
+        ('def f(x: 1, y): ...\nf', [None, None]),
+        ('def f(x: int): ...\nf', ['instance int']),
+        ('from typing import List\ndef f(x: List[int]): ...\nf', ['instance list']),
+        ('from typing import Tuple\ndef f(x: Tuple[int]): ...\nf', ['Tuple: _SpecialForm = ...']),
+        ('x=str\ndef f(p: x): ...\nx=int\nf', ['instance int']),
+    ]
+)
+def test_param_annotation(Script, code, expected_params):
+    func, = Script(code).goto_assignments()
+    sig, = func.get_signatures()
+    for p, expected in zip(sig.params, expected_params):
+        if expected is None:
+            assert not p.infer_annotation()
+        else:
+            annotation, = p.infer_annotation()
+            assert annotation.description == expected