diff --git a/tests/test_exchange.py b/tests/test_exchange.py
new file mode 100644
index 0000000..d4c8808
--- /dev/null
+++ b/tests/test_exchange.py
@@ -0,0 +1,81 @@
+"""Tests for the main mt5bridge exchange class."""
+
+import responses
+import pytest
+
+import mt5bridge_ccxt
+from mt5bridge_ccxt.exceptions import (
+    Mt5BridgeAuthError,
+    Mt5BridgeConnectionError,
+    Mt5BridgeNotConnectedError,
+    Mt5BridgeInvalidRequestError,
+)
+
+
+class TestMt5bridgeInit:
+    def test_id_and_name(self, exchange_config):
+        ex = mt5bridge_ccxt.mt5bridge(exchange_config)
+        assert ex.id == "mt5bridge"
+        assert ex.name == "MT5 Bridge"
+        assert ex.apiKey == exchange_config["apiKey"]
+        assert ex.host == "http://mock-mt5bridge:8080"
+
+    def test_default_host(self):
+        ex = mt5bridge_ccxt.mt5bridge({"apiKey": "x"})
+        assert ex.host == "http://localhost:8080"
+
+    def test_timeframes(self, exchange_config):
+        ex = mt5bridge_ccxt.mt5bridge(exchange_config)
+        assert "1m" in ex.timeframes
+        assert "1h" in ex.timeframes
+        assert "1d" in ex.timeframes
+        assert ex.timeframes["1h"] == "TIMEFRAME_H1"
+
+    def test_mql5_bridge_attached(self, exchange_config):
+        ex = mt5bridge_ccxt.mt5bridge(exchange_config)
+        assert ex.mql5 is not None
+        assert hasattr(ex.mql5, "alpha_trend_signal")
+
+    def test_strip_slash_fallback(self):
+        ex = mt5bridge_ccxt.mt5bridge({
+            "apiKey": "x",
+            "host": "http://h:8080",
+        })
+        # Without symbol_map, falls back to stripping slash
+        assert ex._resolve_mt5_symbol("XAU/USD") == "XAUUSD"
+        assert ex._resolve_mt5_symbol("BTC/USDT") == "BTCUSDT"
+
+    def test_symbol_map_used(self, exchange_config):
+        ex = mt5bridge_ccxt.mt5bridge(exchange_config)
+        assert ex._resolve_mt5_symbol("XAU/USD") == "XAUUSDc"
+        assert ex._resolve_mt5_symbol("EUR/USD") == "EURUSDc"
+
+    def test_reverse_symbol_map(self, exchange_config):
+        ex = mt5bridge_ccxt.mt5bridge(exchange_config)
+        assert ex._resolve_ccxt_symbol("XAUUSDc") == "XAU/USD"
+
+
+class TestErrorHandling:
+    @responses.activate
+    def test_401_raises_auth_error(self, exchange_config):
+        responses.add(responses.GET, "http://mock-mt5bridge:8080/account",
+                      json={"detail": "Unauthorized"}, status=401)
+        ex = mt5bridge_ccxt.mt5bridge(exchange_config)
+        with pytest.raises(Mt5BridgeAuthError):
+            ex.fetch_balance()
+
+    @responses.activate
+    def test_503_raises_not_connected(self, exchange_config):
+        responses.add(responses.GET, "http://mock-mt5bridge:8080/account",
+                      json={"detail": "MT5 not connected"}, status=503)
+        ex = mt5bridge_ccxt.mt5bridge(exchange_config)
+        with pytest.raises(Mt5BridgeNotConnectedError):
+            ex.fetch_balance()
+
+    @responses.activate
+    def test_400_raises_invalid_request(self, exchange_config):
+        responses.add(responses.GET, "http://mock-mt5bridge:8080/account",
+                      json={"detail": "Bad symbol"}, status=400)
+        ex = mt5bridge_ccxt.mt5bridge(exchange_config)
+        with pytest.raises(Mt5BridgeInvalidRequestError):
+            ex.fetch_balance()