Started tests for skeleton module

app/skeleton.py

@@ -1,33 +1,39 @@
 """Handles merging with the skeleton config."""
-from typing import Dict
+from typing import Dict, Union, List
 
 
 class InvalidKeyError(Exception):
     """Thrown when a config file contains an invalid key."""
 
-    def __init__(self, key: str):
+    def __init__(self, keys: Union[str, List[str]]):
         """Create a new InvalidKeyError object with the given key.
 
         Args:
-            key: the invalid key
+            keys: the invalid key(s)
         """
-        self.message = "Invalid key: {}".format(key)
+        if type(keys) == str:
+            keys = [keys]
 
-        super().__init__(key)
+        self.message = "Invalid key(s): {}".format(", ".join(keys))
+
+        super().__init__()
 
 
 class MissingKeyError(Exception):
     """Thrown when a required key is missing from a config."""
 
-    def __init__(self, key: str):
+    def __init__(self, keys: Union[str, List[str]]):
         """Create a new MissingKeyError object with the given key.
 
         Args:
-            key: the invalid key
+            keys: the invalid key(s)
         """
-        self.message = "Missing key: {}".format(key)
+        if type(keys) == str:
+            keys = [keys]
 
-        super().__init__(key)
+        self.message = "Missing key(s): {}".format(", ".join(keys))
+
+        super().__init__()
 
 
 def merge(*dicts: [Dict]) -> Dict:
@@ -93,10 +99,10 @@ def merge_with_skeleton(data: Dict, skel: Dict) -> Dict:
         * Split info less complex functions
     """
     # First, check for illegal keys
-    key = next(key not in skel for key in data)
+    invalid_keys = list(filter(lambda k: k not in skel, data))
 
-    if key:
-        raise InvalidKeyError(key)
+    if invalid_keys:
+        raise InvalidKeyError(invalid_keys)
 
     # Then, check the default values
     for key, value in skel.items():