Define application-specific exceptions

2 files changed, 16 insertions, 4 deletions

diff --git a/jimbrella/database.py b/jimbrella/database.py
index 014b5b5..63cba49 100644
--- a/jimbrella/database.py
+++ b/jimbrella/database.py
@@ -3,6 +3,7 @@ import os
 from datetime import datetime, timedelta
 from .utils import human_datetime, human_timedelta
 from .config import DUE_HOURS
+from .exceptions import *
 
 
 class Database:
@@ -201,9 +202,9 @@ class Database:
         """When a user has borrowed an umbrella."""
         umb = self._find_by_serial(serial)
         if umb is None:
-            raise ValueError(f"No umbrella with serial {serial} found.")
+            raise UmbrellaNotFoundError
         elif umb["status"] != "available":
-            raise ValueError(f"Umbrella with serial {serial} is inavailable.")
+            raise UmbrellaStatusError
         umb["status"] = "lent"
         umb["tenant_name"] = tenant_name
         umb["tenant_id"] = tenant_id
@@ -216,9 +217,9 @@ class Database:
         """When a user has returned an umbrella."""
         umb = self._find_by_serial(serial)
         if umb is None:
-            raise ValueError(f"No umbrella with serial {serial} found.")
+            raise UmbrellaNotFoundError
         elif umb["status"] not in ("lent", "overdue"):
-            raise ValueError(f"Umbrella with serial {serial} is not lent out.")
+            raise UmbrellaStatusError
         umb["status"] = "available"
         for key in ["tenant_name", "tenant_id", "tenant_phone", "tenant_email"]:
             umb[key] = ""
diff --git a/jimbrella/exceptions.py b/jimbrella/exceptions.py
new file mode 100644
index 0000000..3b7fa4c
--- /dev/null
+++ b/jimbrella/exceptions.py
@@ -0,0 +1,11 @@
+"""Defines a few application-specific exceptions for Pythonic code."""
+class UmbrellaNotFoundError(Exception):
+    """For when an umbrella with required serial is not found in database."""
+    pass
+
+
+class UmbrellaStatusError(Exception):
+    """For when the umbrella to be lent is not available, or when an umbrella to be returned has
+    never been taken away. Most likely duplicate or erroneous answer sheets submitted by user.
+    """
+    pass