Add explicit partial buy test

1 files changed, 16 insertions, 0 deletions

diff --git a/test_trade_queue.py b/test_trade_queue.py
index 5e0e434..72c1fda 100644
--- a/test_trade_queue.py
+++ b/test_trade_queue.py
@@ -233,6 +233,22 @@ class TestFIFOQueueMatchTrades(unittest.TestCase):
         # Sell trade amount
         self.assertEqual(matches[0][1].amount, Decimal(5))
 
+    def test_partial_match_partial_buy_trade(self):
+        """Test if a single sell trade removes part of a buy trade."""
+        self.fifo_queue.add_trade(Trade(Decimal(5), Decimal(50), "2025-04-19 10:00:00"))
+        self.fifo_queue.add_trade(
+            Trade(Decimal(-4), Decimal(-75), "2025-04-19 12:00:00")
+        )
+
+        matches = self.fifo_queue.match_trades()
+
+        self.assertEqual(len(matches), 1)
+        # Buy trade amount
+        self.assertEqual(matches[0][0].amount, Decimal(4))
+        # Sell trade amount
+        self.assertEqual(matches[0][1].amount, Decimal(4))
+        self.assertEqual(self.fifo_queue.get_remaining_amount(), 1)
+
     def test_error_single_buy_trade_invalid_order(self):
         """Test if a trade match fails if sell date is before buy date."""
         self.fifo_queue.add_trade(Trade(Decimal(5), Decimal(50), "2025-04-19 10:00:00"))