More tests for imported modules (#1399)

Co-authored-by: Jacob Walls <[email protected]>

Author: tristanlatr

tests/unittest_inference.py

@@ -6627,6 +6627,42 @@ def test_inference_of_items_on_module_dict() -> None:
     builder.file_build(str(DATA_DIR / "module_dict_items_call" / "test.py"), "models")
 
 
+class ImportedModuleTests(resources.AstroidCacheSetupMixin):
+    def test_imported_module_var_inferable(self) -> None:
+        """
+        Module variables can be imported and inferred successfully as part of binary operators.
+        """
+        mod1 = parse(("from top.mod import v as z\n" "w = [1] + z"), module_name="top")
+        parse("v = [2]", module_name="top.mod")
+        w_val = mod1.body[-1].value
+        i_w_val = next(w_val.infer())
+        assert i_w_val != util.Uninferable
+        assert i_w_val.as_string() == "[1, 2]"
+
+    def test_imported_module_var_inferable2(self) -> None:
+        """Version list of strings."""
+        mod1 = parse(
+            ("from top.mod import v as z\n" "w = ['1'] + z"), module_name="top"
+        )
+        parse("v = ['2']", module_name="top.mod")
+        w_val = mod1.body[-1].value
+        i_w_val = next(w_val.infer())
+        assert i_w_val != util.Uninferable
+        assert i_w_val.as_string() == "['1', '2']"
+
+    def test_imported_module_var_inferable3(self) -> None:
+        """Version list of strings with a __dunder__ name."""
+        mod1 = parse(
+            ("from top.mod import __dunder_var__ as v\n" "__dunder_var__ = ['w'] + v"),
+            module_name="top",
+        )
+        parse("__dunder_var__ = ['v']", module_name="top.mod")
+        w_val = mod1.body[-1].value
+        i_w_val = next(w_val.infer())
+        assert i_w_val != util.Uninferable
+        assert i_w_val.as_string() == "['w', 'v']"
+
+
 def test_recursion_on_inference_tip() -> None:
     """Regression test for recursion in inference tip.