integration tests

core/health/ports/HealthCheckQuery.ts

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+/**
+ * Health Check Query Port
+ * 
+ * Defines the interface for querying health status.
+ * This port is implemented by adapters that can perform health checks.
+ */
+
+export interface HealthCheckQuery {
+  /**
+   * Perform a health check
+   */
+  performHealthCheck(): Promise<HealthCheckResult>;
+  
+  /**
+   * Get current connection status
+   */
+  getStatus(): ConnectionStatus;
+  
+  /**
+   * Get detailed health information
+   */
+  getHealth(): ConnectionHealth;
+  
+  /**
+   * Get reliability percentage
+   */
+  getReliability(): number;
+  
+  /**
+   * Check if API is currently available
+   */
+  isAvailable(): boolean;
+}
+
+export type ConnectionStatus = 'connected' | 'disconnected' | 'degraded' | 'checking';
+
+export interface ConnectionHealth {
+  status: ConnectionStatus;
+  lastCheck: Date | null;
+  lastSuccess: Date | null;
+  lastFailure: Date | null;
+  consecutiveFailures: number;
+  totalRequests: number;
+  successfulRequests: number;
+  failedRequests: number;
+  averageResponseTime: number;
+}
+
+export interface HealthCheckResult {
+  healthy: boolean;
+  responseTime: number;
+  error?: string;
+  timestamp: Date;
+}

core/health/ports/HealthEventPublisher.ts

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+/**
+ * Health Event Publisher Port
+ * 
+ * Defines the interface for publishing health-related events.
+ * This port is implemented by adapters that can publish events.
+ */
+
+export interface HealthEventPublisher {
+  /**
+   * Publish a health check completed event
+   */
+  publishHealthCheckCompleted(event: HealthCheckCompletedEvent): Promise<void>;
+  
+  /**
+   * Publish a health check failed event
+   */
+  publishHealthCheckFailed(event: HealthCheckFailedEvent): Promise<void>;
+  
+  /**
+   * Publish a health check timeout event
+   */
+  publishHealthCheckTimeout(event: HealthCheckTimeoutEvent): Promise<void>;
+  
+  /**
+   * Publish a connected event
+   */
+  publishConnected(event: ConnectedEvent): Promise<void>;
+  
+  /**
+   * Publish a disconnected event
+   */
+  publishDisconnected(event: DisconnectedEvent): Promise<void>;
+  
+  /**
+   * Publish a degraded event
+   */
+  publishDegraded(event: DegradedEvent): Promise<void>;
+  
+  /**
+   * Publish a checking event
+   */
+  publishChecking(event: CheckingEvent): Promise<void>;
+}
+
+export interface HealthCheckCompletedEvent {
+  healthy: boolean;
+  responseTime: number;
+  timestamp: Date;
+  endpoint?: string;
+}
+
+export interface HealthCheckFailedEvent {
+  error: string;
+  timestamp: Date;
+  endpoint?: string;
+}
+
+export interface HealthCheckTimeoutEvent {
+  timestamp: Date;
+  endpoint?: string;
+}
+
+export interface ConnectedEvent {
+  timestamp: Date;
+  responseTime: number;
+}
+
+export interface DisconnectedEvent {
+  timestamp: Date;
+  consecutiveFailures: number;
+}
+
+export interface DegradedEvent {
+  timestamp: Date;
+  reliability: number;
+}
+
+export interface CheckingEvent {
+  timestamp: Date;
+}

core/health/use-cases/CheckApiHealthUseCase.ts

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+/**
+ * CheckApiHealthUseCase
+ * 
+ * Executes health checks and returns status.
+ * This Use Case orchestrates the health check process and emits events.
+ */
+
+import { HealthCheckQuery, HealthCheckResult } from '../ports/HealthCheckQuery';
+import { HealthEventPublisher } from '../ports/HealthEventPublisher';
+
+export interface CheckApiHealthUseCasePorts {
+  healthCheckAdapter: HealthCheckQuery;
+  eventPublisher: HealthEventPublisher;
+}
+
+export class CheckApiHealthUseCase {
+  constructor(private readonly ports: CheckApiHealthUseCasePorts) {}
+
+  /**
+   * Execute a health check
+   */
+  async execute(): Promise<HealthCheckResult> {
+    const { healthCheckAdapter, eventPublisher } = this.ports;
+
+    try {
+      // Perform the health check
+      const result = await healthCheckAdapter.performHealthCheck();
+
+      // Emit appropriate event based on result
+      if (result.healthy) {
+        await eventPublisher.publishHealthCheckCompleted({
+          healthy: result.healthy,
+          responseTime: result.responseTime,
+          timestamp: result.timestamp,
+        });
+      } else {
+        await eventPublisher.publishHealthCheckFailed({
+          error: result.error || 'Unknown error',
+          timestamp: result.timestamp,
+        });
+      }
+
+      return result;
+    } catch (error) {
+      const errorMessage = error instanceof Error ? error.message : 'Unknown error';
+      const timestamp = new Date();
+
+      // Emit failed event
+      await eventPublisher.publishHealthCheckFailed({
+        error: errorMessage,
+        timestamp,
+      });
+
+      return {
+        healthy: false,
+        responseTime: 0,
+        error: errorMessage,
+        timestamp,
+      };
+    }
+  }
+}

core/health/use-cases/GetConnectionStatusUseCase.ts

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+/**
+ * GetConnectionStatusUseCase
+ * 
+ * Retrieves current connection status and metrics.
+ * This Use Case orchestrates the retrieval of connection status information.
+ */
+
+import { HealthCheckQuery, ConnectionHealth, ConnectionStatus } from '../ports/HealthCheckQuery';
+
+export interface GetConnectionStatusUseCasePorts {
+  healthCheckAdapter: HealthCheckQuery;
+}
+
+export interface ConnectionStatusResult {
+  status: ConnectionStatus;
+  reliability: number;
+  totalRequests: number;
+  successfulRequests: number;
+  failedRequests: number;
+  consecutiveFailures: number;
+  averageResponseTime: number;
+  lastCheck: Date | null;
+  lastSuccess: Date | null;
+  lastFailure: Date | null;
+}
+
+export class GetConnectionStatusUseCase {
+  constructor(private readonly ports: GetConnectionStatusUseCasePorts) {}
+
+  /**
+   * Execute to get current connection status
+   */
+  async execute(): Promise<ConnectionStatusResult> {
+    const { healthCheckAdapter } = this.ports;
+
+    const health = healthCheckAdapter.getHealth();
+    const reliability = healthCheckAdapter.getReliability();
+
+    return {
+      status: health.status,
+      reliability,
+      totalRequests: health.totalRequests,
+      successfulRequests: health.successfulRequests,
+      failedRequests: health.failedRequests,
+      consecutiveFailures: health.consecutiveFailures,
+      averageResponseTime: health.averageResponseTime,
+      lastCheck: health.lastCheck,
+      lastSuccess: health.lastSuccess,
+      lastFailure: health.lastFailure,
+    };
+  }
+}