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/multi-region-load-balancer/tests/test_unit_multi_region_load_balancer.py

@@ -0,0 +1,120 @@
+"""Unit tests for multi-region load balancer service"""
+
+import pytest
+import sys
+import sys
+from pathlib import Path
+from datetime import datetime
+
+
+from main import app, LoadBalancingRule, RegionHealth, LoadBalancingMetrics, GeographicRule
+
+
+@pytest.mark.unit
+def test_app_initialization():
+    """Test that the FastAPI app initializes correctly"""
+    assert app is not None
+    assert app.title == "AITBC Multi-Region Load Balancer"
+    assert app.version == "1.0.0"
+
+
+@pytest.mark.unit
+def test_load_balancing_rule_model():
+    """Test LoadBalancingRule model"""
+    rule = LoadBalancingRule(
+        rule_id="rule_123",
+        name="Test Rule",
+        algorithm="weighted_round_robin",
+        target_regions=["us-east-1", "eu-west-1"],
+        weights={"us-east-1": 0.5, "eu-west-1": 0.5},
+        health_check_path="/health",
+        failover_enabled=True,
+        session_affinity=False
+    )
+    assert rule.rule_id == "rule_123"
+    assert rule.name == "Test Rule"
+    assert rule.algorithm == "weighted_round_robin"
+    assert rule.failover_enabled is True
+    assert rule.session_affinity is False
+
+
+@pytest.mark.unit
+def test_region_health_model():
+    """Test RegionHealth model"""
+    health = RegionHealth(
+        region_id="us-east-1",
+        status="healthy",
+        response_time_ms=45.5,
+        success_rate=0.99,
+        active_connections=100,
+        last_check=datetime.utcnow()
+    )
+    assert health.region_id == "us-east-1"
+    assert health.status == "healthy"
+    assert health.response_time_ms == 45.5
+    assert health.success_rate == 0.99
+    assert health.active_connections == 100
+
+
+@pytest.mark.unit
+def test_load_balancing_metrics_model():
+    """Test LoadBalancingMetrics model"""
+    metrics = LoadBalancingMetrics(
+        balancer_id="lb_123",
+        timestamp=datetime.utcnow(),
+        total_requests=1000,
+        requests_per_region={"us-east-1": 500, "eu-west-1": 500},
+        average_response_time=50.5,
+        error_rate=0.001,
+        throughput=100.0
+    )
+    assert metrics.balancer_id == "lb_123"
+    assert metrics.total_requests == 1000
+    assert metrics.average_response_time == 50.5
+    assert metrics.error_rate == 0.001
+
+
+@pytest.mark.unit
+def test_geographic_rule_model():
+    """Test GeographicRule model"""
+    rule = GeographicRule(
+        rule_id="geo_123",
+        source_regions=["us-east", "us-west"],
+        target_regions=["us-east-1", "us-west-1"],
+        priority=1,
+        latency_threshold_ms=50.0
+    )
+    assert rule.rule_id == "geo_123"
+    assert rule.source_regions == ["us-east", "us-west"]
+    assert rule.priority == 1
+    assert rule.latency_threshold_ms == 50.0
+
+
+@pytest.mark.unit
+def test_load_balancing_rule_empty_weights():
+    """Test LoadBalancingRule with empty weights"""
+    rule = LoadBalancingRule(
+        rule_id="rule_123",
+        name="Test Rule",
+        algorithm="round_robin",
+        target_regions=["us-east-1"],
+        weights={},
+        health_check_path="/health",
+        failover_enabled=False,
+        session_affinity=False
+    )
+    assert rule.weights == {}
+
+
+@pytest.mark.unit
+def test_region_health_negative_response_time():
+    """Test RegionHealth with negative response time"""
+    health = RegionHealth(
+        region_id="us-east-1",
+        status="healthy",
+        response_time_ms=-45.5,
+        success_rate=0.99,
+        active_connections=100,
+        last_check=datetime.utcnow()
+    )
+    assert health.response_time_ms == -45.5