From 8c38c0244f8c530bc7a4d67d7f70bb59af942a63 Mon Sep 17 00:00:00 2001
From: Florian Fischer <florian.fl.fischer@fau.de>
Date: Tue, 28 Apr 2020 17:41:06 +0200
Subject: prevent crashes when money should be transfered to the issuer

---
 geldschieberbot.py | 22 +++++++++++++++-------
 test.py            | 18 ++++++++++++++++++
 2 files changed, 33 insertions(+), 7 deletions(-)

diff --git a/geldschieberbot.py b/geldschieberbot.py
index c249dd2..44327e1 100644
--- a/geldschieberbot.py
+++ b/geldschieberbot.py
@@ -72,9 +72,11 @@ def record(recipient, donor, amount):
     """Apply changes to the balance"""
 
     # Only change anything if this is not a dry run
-    if not dry_run:
-        balance[donor][recipient] += amount
-        balance[recipient][donor] -= amount
+    if dry_run:
+        return
+
+    balance[donor][recipient] += amount
+    balance[recipient][donor] -= amount
 
 def to_cent(euro):
     if '.' in euro:
@@ -275,11 +277,14 @@ def split(sender, args, msg):
     output = f"Split {to_euro(amount)} between {persons} -> {to_euro(amount_per_person)} each\n"
     change = [args]
     for p in args[2:]:
-        if not p in name2num:
-            output += p + " not known. Please take care manually\n"
+        if p in name2num:
+            if p == recipient:
+                output += f"{p}, you will be charged multiple times. This may not be what you want\n"
+            else:
+                record(recipient, p, amount_per_person)
+                change.append([recipient, p, amount_per_person])
         else:
-            record(recipient, p, amount_per_person)
-            change.append([recipient, p, amount_per_person])
+            output += f"{p} not known. Please take care manually\n"
 
     if record_changes and not dry_run:
         changes[recipient].append(change)
@@ -307,6 +312,9 @@ def transaction(sender, args, msg):
     else:
         return None, 'recipient not known'
 
+    if sender == recipient:
+        return None, 'you can not transfere money to or from yourself'
+
     try:
         amount = to_cent(amount)
     except:
diff --git a/test.py b/test.py
index 94235e1..929605c 100755
--- a/test.py
+++ b/test.py
@@ -197,6 +197,13 @@ class TestTransactionCmd(unittest.TestCase):
 
         compare_state("test/state.json_transactions1")
 
+    def test_transactions_with_myself(self):
+        res = run_bot(self, num[alice], f"!schieb {alice} 1,1")
+        self.assertEqual(res.stdout, 'ERROR: you can not transfere money to or from yourself')
+
+        res = run_bot(self, num[alice], f"!zieh {alice} 2.1")
+        self.assertEqual(res.stdout, 'ERROR: you can not transfere money to or from yourself')
+
 class TestSumCmd(unittest.TestCase):
     def test_summary_single_user(self):
         reset_state("test/state.json_transactions1")
@@ -297,6 +304,17 @@ foo not known. Please take care manually
 New Balance:
 alice:
 \t<- charlie 10.00
+\tBalance: 10.00"""
+        self.assertEqual(res.stdout, msg)
+
+    def test_split_with_sender_in_user_list(self):
+        res = run_bot(self, num[alice], f"!split 30 {charlie} {alice}")
+        msg = \
+"""Split 30.00 between 3 -> 10.00 each
+alice, you will be charged multiple times. This may not be what you want
+New Balance:
+alice:
+\t<- charlie 10.00
 \tBalance: 10.00"""
         self.assertEqual(res.stdout, msg)
     
-- 
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