Add sys import to test files and remove obsolete integration tests

- Add sys import to 29 test files across agent-coordinator, blockchain-event-bridge, blockchain-node, and coordinator-api
- Remove apps/blockchain-event-bridge/tests/test_integration.py (obsolete bridge integration tests)
- Remove apps/coordinator-api/tests/test_integration.py (obsolete API integration tests)
- Implement GPU registration in marketplace_gpu.py with GPURegistry model persistence

apps/exchange-integration/tests/test_unit_exchange_integration.py

@@ -0,0 +1,101 @@
+"""Unit tests for exchange integration service"""
+
+import pytest
+import sys
+import sys
+from pathlib import Path
+from unittest.mock import Mock, patch
+
+
+# Mock aiohttp before importing
+sys.modules['aiohttp'] = Mock()
+
+from main import app, ExchangeRegistration, TradingPair, OrderRequest
+
+
+@pytest.mark.unit
+def test_app_initialization():
+    """Test that the FastAPI app initializes correctly"""
+    assert app is not None
+    assert app.title == "AITBC Exchange Integration Service"
+    assert app.version == "1.0.0"
+
+
+@pytest.mark.unit
+def test_exchange_registration_model():
+    """Test ExchangeRegistration model"""
+    registration = ExchangeRegistration(
+        name="TestExchange",
+        api_key="test_key_123",
+        sandbox=True,
+        description="Test exchange"
+    )
+    assert registration.name == "TestExchange"
+    assert registration.api_key == "test_key_123"
+    assert registration.sandbox is True
+    assert registration.description == "Test exchange"
+
+
+@pytest.mark.unit
+def test_exchange_registration_defaults():
+    """Test ExchangeRegistration default values"""
+    registration = ExchangeRegistration(
+        name="TestExchange",
+        api_key="test_key_123"
+    )
+    assert registration.name == "TestExchange"
+    assert registration.api_key == "test_key_123"
+    assert registration.sandbox is True
+    assert registration.description is None
+
+
+@pytest.mark.unit
+def test_trading_pair_model():
+    """Test TradingPair model"""
+    pair = TradingPair(
+        symbol="AITBC/BTC",
+        base_asset="AITBC",
+        quote_asset="BTC",
+        min_order_size=0.001,
+        price_precision=8,
+        quantity_precision=6
+    )
+    assert pair.symbol == "AITBC/BTC"
+    assert pair.base_asset == "AITBC"
+    assert pair.quote_asset == "BTC"
+    assert pair.min_order_size == 0.001
+    assert pair.price_precision == 8
+    assert pair.quantity_precision == 6
+
+
+@pytest.mark.unit
+def test_order_request_model():
+    """Test OrderRequest model"""
+    order = OrderRequest(
+        symbol="AITBC/BTC",
+        side="buy",
+        type="limit",
+        quantity=100.0,
+        price=0.00001
+    )
+    assert order.symbol == "AITBC/BTC"
+    assert order.side == "buy"
+    assert order.type == "limit"
+    assert order.quantity == 100.0
+    assert order.price == 0.00001
+
+
+@pytest.mark.unit
+def test_order_request_market_order():
+    """Test OrderRequest for market order"""
+    order = OrderRequest(
+        symbol="AITBC/BTC",
+        side="sell",
+        type="market",
+        quantity=50.0
+    )
+    assert order.symbol == "AITBC/BTC"
+    assert order.side == "sell"
+    assert order.type == "market"
+    assert order.quantity == 50.0
+    assert order.price is None