Moved exceptions to own file; added some more tests

app/exceptions.py

@@ -0,0 +1,36 @@
+"""Common exceptions raised by the program."""
+from typing import Union, List
+
+
+class InvalidKeyError(Exception):
+    """Thrown when a config file contains an invalid key."""
+
+    def __init__(self, keys: Union[str, List[str]]):
+        """Create a new InvalidKeyError object with the given key.
+
+        Args:
+            keys: the invalid key(s)
+        """
+        if type(keys) == str:
+            keys = [keys]
+
+        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, keys: Union[str, List[str]]):
+        """Create a new MissingKeyError object with the given key.
+
+        Args:
+            keys: the invalid key(s)
+        """
+        if type(keys) == str:
+            keys = [keys]
+
+        self.message = "Missing key(s): {}".format(", ".join(keys))
+
+        super().__init__()

app/skeleton.py

@@ -1,39 +1,6 @@
 """Handles merging with the skeleton config."""
-from typing import Dict, Union, List
-
-
-class InvalidKeyError(Exception):
-    """Thrown when a config file contains an invalid key."""
-
-    def __init__(self, keys: Union[str, List[str]]):
-        """Create a new InvalidKeyError object with the given key.
-
-        Args:
-            keys: the invalid key(s)
-        """
-        if type(keys) == str:
-            keys = [keys]
-
-        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, keys: Union[str, List[str]]):
-        """Create a new MissingKeyError object with the given key.
-
-        Args:
-            keys: the invalid key(s)
-        """
-        if type(keys) == str:
-            keys = [keys]
-
-        self.message = "Missing key(s): {}".format(", ".join(keys))
-
-        super().__init__()
+from typing import Dict
+from .exceptions import InvalidKeyError, MissingKeyError
 
 
 def merge(*dicts: [Dict]) -> Dict: