Added unit tests for new utils.get_types function

Author: tleonhardt

cmd2/utils.py

@@ -1258,7 +1258,10 @@ def get_types(func_or_method: Callable[..., Any]) -> tuple[dict[str, Any], Any]:
     :return tuple with first element being dictionary mapping param names to type hints
             and second element being return type hint, unspecified, returns None
     """
-    type_hints = get_type_hints(func_or_method)  # Get dictionary of type hints
+    try:
+        type_hints = get_type_hints(func_or_method)  # Get dictionary of type hints
+    except TypeError as exc:
+        raise ValueError("Argument passed to get_types should be a function or method") from exc
     ret_ann = type_hints.pop('return', None)  # Pop off the return annotation if it exists
     if inspect.ismethod(func_or_method):
         type_hints.pop('self', None)  # Pop off `self` hint for methods

tests/test_utils.py

@@ -892,3 +892,44 @@ def custom_similarity_function(s1, s2) -> float:
 
     suggested_command = cu.suggest_similar("test", ["test"], similarity_function_to_use=custom_similarity_function)
     assert suggested_command is None
+
+
+def test_get_types_invalid_input() -> None:
+    x = 1
+    with pytest.raises(ValueError, match="Argument passed to get_types should be a function or method"):
+        cu.get_types(x)
+
+
+def test_get_types_empty() -> None:
+    def a(b):
+        print(b)
+
+    param_ann, ret_ann = cu.get_types(a)
+    assert ret_ann is None
+    assert param_ann == {}
+
+
+def test_get_types_non_empty() -> None:
+    def foo(x: int) -> str:
+        return f"{x * x}"
+
+    param_ann, ret_ann = cu.get_types(foo)
+    assert ret_ann is str
+    param_name, param_value = next(iter(param_ann.items()))
+    assert param_name == 'x'
+    assert param_value is int
+
+
+def test_get_types_method() -> None:
+    class Foo:
+        def bar(self, x: bool) -> None:
+            print(x)
+
+    f = Foo()
+
+    param_ann, ret_ann = cu.get_types(f.bar)
+    assert ret_ann is None
+    assert len(param_ann) == 1
+    param_name, param_value = next(iter(param_ann.items()))
+    assert param_name == 'x'
+    assert param_value is bool