Implement Kraken integration with REST and WebSocket clients, add market data handling, and enhance settings configuration

tests/unit/test_order_book.py

@@ -0,0 +1,27 @@
+from arbitrade.exchange.models import BookLevel
+from arbitrade.market_data.order_book import OrderBook
+
+
+def test_order_book_apply_and_best_levels() -> None:
+    book = OrderBook()
+    book.apply_bids([BookLevel(price=100.0, volume=1.0), BookLevel(price=99.5, volume=2.0)])
+    book.apply_asks([BookLevel(price=100.5, volume=1.1), BookLevel(price=101.0, volume=0.9)])
+
+    best_bid = book.best_bid()
+    best_ask = book.best_ask()
+
+    assert best_bid is not None
+    assert best_ask is not None
+    assert best_bid.price == 100.0
+    assert best_ask.price == 100.5
+
+
+def test_order_book_checksum_matches_self() -> None:
+    book = OrderBook()
+    book.apply_bids([BookLevel(price=100.0, volume=1.0)])
+    book.apply_asks([BookLevel(price=100.5, volume=1.0)])
+
+    checksum = book.compute_checksum()
+
+    assert isinstance(checksum, int)
+    assert checksum == book.compute_checksum()