A work in progress improvement for compiled signatures

test/test_evaluate/test_signature.py

@@ -0,0 +1,15 @@
+import pytest
+
+from jedi.evaluate.gradual.conversion import stub_to_actual_context_set
+
+
+def test_compiled_signature(Script):
+    code = 'import math; math.cos'
+    sig = 'cos(x, /)'
+    d, = Script(code).goto_definitions()
+    context, = d._name.infer()
+    compiled, = stub_to_actual_context_set(context)
+    signature, = compiled.get_signatures()
+    assert signature.to_string() == sig
+    assert signature.get_param_names() == []
+    assert signature.annotation is None