Update QueryStringTransformer to raise KeyError for non-existent parameters instead of AttributeError

Author: ahosgood

CHANGELOG.md

@@ -15,6 +15,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Changed
 
+- Transformations to non-existent keys in `QueryStringTransformer` now throw `KeyError` rather than `AttributeError`
+
 ### Deprecated
 
 ### Removed

tests/test_url.py

@@ -35,11 +35,15 @@ def lists(self):
         self.assertEqual(manipulator.add_parameter("foo", "bar"), manipulator)
         self.assertEqual(manipulator.get_query_string(), "?a=1&b=2&b=3&foo=bar")
 
+    def test_unhappy_init(self):
+        with self.assertRaises(AttributeError):
+            QueryStringTransformer(0)
+
     def test_parameter_values(self):
         manipulator = QueryStringTransformer(self.test_query)
         self.assertEqual(manipulator.parameter_values("a"), ["1"])
         self.assertEqual(manipulator.parameter_values("b"), ["2", "3"])
-        with self.assertRaises(AttributeError):
+        with self.assertRaises(KeyError):
             manipulator.parameter_values("c")
 
     def test_add_parameter(self):
@@ -89,7 +93,7 @@ def test_remove_parameter(self):
         self.assertFalse(manipulator.parameter_exists("a"))
         self.assertEqual(manipulator.remove_parameter("b"), manipulator)
         self.assertFalse(manipulator.parameter_exists("b"))
-        with self.assertRaises(AttributeError):
+        with self.assertRaises(KeyError):
             self.assertEqual(manipulator.remove_parameter("c"), manipulator)
         self.assertEqual(manipulator.get_query_string(), "?")
 
@@ -99,7 +103,7 @@ def test_is_value_in_parameter(self):
         self.assertTrue(manipulator.is_value_in_parameter("b", "2"))
         self.assertTrue(manipulator.is_value_in_parameter("b", "3"))
         self.assertFalse(manipulator.is_value_in_parameter("b", "4"))
-        with self.assertRaises(AttributeError):
+        with self.assertRaises(KeyError):
             self.assertFalse(manipulator.is_value_in_parameter("c", "5"))
 
     def test_toggle_parameter_value(self):

tna_utilities/url.py

@@ -18,7 +18,7 @@ def __init__(self, args=None) -> None:
             try:
                 args_lists = args.lists()
             except AttributeError:
-                raise TypeError(
+                raise AttributeError(
                     "args must be an ImmutableMultiDict (Django), a QueryDict (Flask) object or an iterable of (key, [values]) tuples"
                 )
             self.args = list(args_lists)
@@ -38,13 +38,13 @@ def parameter_exists(self, parameter) -> bool:
     def parameter_values(self, parameter: str) -> list:
         """
         Get the values associated with a parameter in the query parameters.
-        Raises an AttributeError if the parameter does not exist.
+        Raises an KeyError if the parameter does not exist.
         """
 
         for key, values in self.args:
             if key == parameter:
                 return values
-        raise AttributeError(f"Parameter '{parameter}' does not exist")
+        raise KeyError(f"Parameter '{parameter}' does not exist")
 
     def add_parameter(
         self, parameter: str, values: str | int | list | None = None
@@ -80,48 +80,48 @@ def update_parameter(
     def remove_parameter(self, parameter: str) -> "QueryStringTransformer":
         """
         Remove a parameter from the query parameters.
-        Raises an AttributeError if the parameter does not exist.
+        Raises an KeyError if the parameter does not exist.
         """
 
         for key, vals in self.args:
             if key == parameter:
                 self.args.remove((key, vals))
                 return self
-        raise AttributeError(f"Parameter '{parameter}' does not exist")
+        raise KeyError(f"Parameter '{parameter}' does not exist")
 
     def is_value_in_parameter(self, parameter: str, value: str | int) -> bool:
         """
         Check if a specific value exists within a parameter's values.
-        Raises an AttributeError if the parameter does not exist.
+        Raises an KeyError if the parameter does not exist.
         """
 
         for key, values in self.args:
             if key == parameter:
                 return str(value) in values
-        raise AttributeError(f"Parameter '{parameter}' does not exist")
+        raise KeyError(f"Parameter '{parameter}' does not exist")
 
     def add_parameter_value(
         self, parameter: str, value: str | int
     ) -> "QueryStringTransformer":
         """
         Add a specific value to a parameter's values.
-        Raises an AttributeError if the parameter does not exist.
+        Raises an KeyError if the parameter does not exist.
         """
 
         for key, values in self.args:
             if key == parameter:
                 if str(value) not in values:
                     values.append(str(value))
                 return self
-        raise AttributeError(f"Parameter '{parameter}' does not exist")
+        raise KeyError(f"Parameter '{parameter}' does not exist")
 
     def toggle_parameter_value(
         self, parameter: str, value: str | int
     ) -> "QueryStringTransformer":
         """
         Toggle a value within a parameter's values.
         If the value exists, it will be removed; if it does not exist, it will be added.
-        Raises an AttributeError if the parameter does not exist.
+        Raises an KeyError if the parameter does not exist.
         """
 
         for key, values in self.args:
@@ -131,22 +131,22 @@ def toggle_parameter_value(
                 else:
                     self.add_parameter_value(parameter, value)
                 return self
-        raise AttributeError(f"Parameter '{parameter}' does not exist")
+        raise KeyError(f"Parameter '{parameter}' does not exist")
 
     def remove_parameter_value(
         self, parameter: str, value: str | int
     ) -> "QueryStringTransformer":
         """
         Remove a specific value from a parameter's values.
-        Raises an AttributeError if the parameter does not exist.
+        Raises an KeyError if the parameter does not exist.
         """
 
         for key, values in self.args:
             if key == parameter:
                 if str(value) in values:
                     values.remove(str(value))
                 return self
-        raise AttributeError(f"Parameter '{parameter}' does not exist")
+        raise KeyError(f"Parameter '{parameter}' does not exist")
 
     def get_query_string(self) -> str:
         """