feat: add RoutingError exception class and export

Author: nathanjmcdougall

src/yamltrip/__init__.py

@@ -14,6 +14,7 @@
     ParseError,
     PatchError,
     QueryError,
+    RoutingError,
     YAMLTripError,
 )
 
@@ -52,6 +53,7 @@ def edit(path: str | Path) -> Editor:
     "PatchError",
     "QueryError",
     "Route",
+    "RoutingError",
     "YAMLTripError",
     "edit",
     "load",

src/yamltrip/errors.py

@@ -25,5 +25,9 @@ class KeyMissingError(PatchError):
     """Raised by replace() when the key doesn't exist."""
 
 
+class RoutingError(PatchError):
+    """Raised when a key path passes through a non-mapping node."""
+
+
 class NodeTypeError(PatchError, TypeError):
     """Raised when a node is not the expected type for the operation."""

tests/test_errors.py

@@ -7,6 +7,7 @@
     ParseError,
     PatchError,
     QueryError,
+    RoutingError,
     YAMLTripError,
 )
 
@@ -38,3 +39,23 @@ def test_raise_and_catch_base(self):
         msg = "key already exists"
         with pytest.raises(YAMLTripError, match=msg):
             raise KeyExistsError(msg)
+
+
+class TestRoutingErrorHierarchy:
+    def test_routing_error_is_patch_error(self):
+        assert issubclass(RoutingError, PatchError)
+
+    def test_routing_error_is_not_type_error(self):
+        assert not issubclass(RoutingError, TypeError)
+
+    def test_routing_error_is_not_node_type_error(self):
+        assert not issubclass(RoutingError, NodeTypeError)
+
+    def test_raise_and_catch_as_patch_error(self):
+        msg = "route through scalar"
+        with pytest.raises(PatchError):
+            raise RoutingError(msg)
+
+    def test_message(self):
+        err = RoutingError("Route passes through a non-mapping node at a")
+        assert "a" in str(err)

tests/test_public_api.py

@@ -39,6 +39,7 @@ def test_error_classes(self):
         assert issubclass(yamltrip.PatchError, yamltrip.YAMLTripError)
         assert issubclass(yamltrip.KeyExistsError, yamltrip.PatchError)
         assert issubclass(yamltrip.KeyMissingError, yamltrip.PatchError)
+        assert issubclass(yamltrip.RoutingError, yamltrip.PatchError)
 
     def test_core_types(self):
         assert yamltrip.Location is not None