dmsc 0.1.9

//! Copyright © 2025-2026 Wenze Wei. All Rights Reserved.
//!
//! This file is part of Ri.
//! The Ri project belongs to the Dunimd Team.
//!
//! Licensed under the Apache License, Version 2.0 (the "License");
//! You may not use this file except in compliance with the License.
//! You may obtain a copy of the License at
//!
//!     http://www.apache.org/licenses/LICENSE-2.0
//!
//! Unless required by applicable law or agreed to in writing, software
//! distributed under the License is distributed on an "AS IS" BASIS,
//! WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
//! See the License for the specific language governing permissions and
//! limitations under the License.

//! # Service Mesh Module Tests
//!
//! This module contains comprehensive tests for the Ri service mesh system,
//! providing service discovery, health checking, traffic management, circuit breaking,
//! and load balancing for building resilient microservice architectures.
//!
//! ## Test Coverage
//!
//! - **RiServiceMeshConfig**: Tests for service mesh configuration including feature
//!   toggles (discovery, health checks, traffic management), intervals, timeouts, and
//!   retry policies
//!
//! - **RiServiceMesh**: Tests for the core service mesh orchestrating all components
//!   including service registry, health checker, traffic manager, circuit breaker, and
//!   load balancer
//!
//! - **RiServiceInstance**: Tests for service instance representation including
//!   identification, endpoint information, status, metadata, and heartbeat tracking
//!
//! - **RiHealthCheck**: Tests for health checking including result structures,
//!   summary aggregation, success rate tracking, and response time monitoring
//!
//! - **RiTrafficRoute**: Tests for traffic routing including match criteria (path,
//!   headers, method, query), weighted destinations, retry policies, timeouts, and
//!   fault injection configuration
//!
//! - **RiServiceStatus**: Tests for service instance states (Running, Stopped, Unknown)
//!
//! ## Architecture
//!
//! The service mesh implements a sidecar-less architecture for Ri services:
//! - **Service Discovery**: Registry mapping service names to healthy instances
//! - **Health Checking**: Active and passive health verification with configurable intervals
//! - **Traffic Management**: Advanced routing with subset-based deployments and traffic shifting
//! - **Resilience**: Circuit breaking, retry policies, and timeouts for fault tolerance
//! - **Load Balancing**: Multiple strategies with consistent hashing support
//!
//! ## Health Check States
//!
//! The health system tracks service availability:
//! - **Healthy**: Service passes health checks and receives traffic
//! - **Unhealthy**: Service failed checks and is temporarily excluded
//! - **Unknown**: Initial state before first health check completes
//!
//! Health checks can be configured with:
//! - **Interval**: How often to check service health
//! - **Timeout**: Maximum wait for health check response
//! - **Unhealthy Threshold**: Consecutive failures before marking unhealthy
//! - **Healthy Threshold**: Consecutive successes before marking healthy
//!
//! ## Traffic Routing
//!
//! Traffic routes enable sophisticated traffic management:
//! - **Subset Routing**: Route to specific service versions (canary, blue-green)
//! - **Weight-Based Routing**: Split traffic between destinations
//! - **Header-Based Routing**: Route based on request headers
//! - **Path-Based Routing**: Match requests by path prefix or exact match
//!
//! ## Resilience Patterns
//!
//! The service mesh implements multiple resilience patterns:
//! - **Circuit Breaker**: Prevents cascade failures by failing fast
//! - **Retry Policies**: Automatic retries with exponential backoff
//! - **Timeouts**: Request timeout enforcement
//! - **Fault Injection**: Inject delays and aborts for chaos testing

use ri::service_mesh::{RiServiceMeshConfig, RiServiceMesh, RiServiceHealthStatus, RiServiceEndpoint};
use ri::service_mesh::{RiServiceInstance, RiServiceStatus};
use ri::service_mesh::{RiHealthCheckResult, RiHealthSummary, RiHealthStatus};
use ri::service_mesh::{RiTrafficRoute, RiMatchCriteria, RiRouteAction};

#[test]
/// Tests RiServiceMeshConfig default configuration values.
///
/// Verifies that the service mesh configuration has appropriate defaults
/// for feature toggles, intervals, timeouts, and retry policies.
///
/// ## Default Configuration Values
///
/// - **enable_service_discovery**: true - Service discovery is enabled
/// - **enable_health_check**: true - Health checking is enabled
/// - **enable_traffic_management**: true - Traffic management is enabled
/// - **health_check_interval**: 30 seconds - Frequency of health checks
/// - **max_retry_attempts**: 3 - Maximum retry attempts for failed requests
/// - **retry_timeout**: 5 seconds - Timeout for retry attempts
///
/// ## Feature Toggles
///
/// The service mesh supports enabling/disabling key capabilities:
/// - Service Discovery: Registry for service-to-service location
/// - Health Checking: Active monitoring of service availability
/// - Traffic Management: Advanced routing and流量控制
///
/// ## Expected Behavior
///
/// All feature toggles are enabled by default, providing a fully
/// functional service mesh without additional configuration.
fn test_service_mesh_config_default() {
    let config = RiServiceMeshConfig::default();
    
    // Verify feature toggles are enabled
    assert!(config.enable_service_discovery);
    assert!(config.enable_health_check);
    assert!(config.enable_traffic_management);
    
    // Verify timing configuration
    assert_eq!(config.health_check_interval.as_secs(), 30);
    assert_eq!(config.max_retry_attempts, 3);
    assert_eq!(config.retry_timeout.as_secs(), 5);
}

#[test]
/// Tests RiServiceMesh creation and component initialization.
///
/// Verifies that a service mesh can be created with the specified
/// configuration and all internal components are properly initialized.
///
/// ## Service Mesh Components
///
/// The service mesh orchestrates multiple components:
/// - **Service Discovery**: Registry for service instance mapping
/// - **Health Checker**: Active monitoring of service health
/// - **Traffic Manager**: Routing and流量控制
/// - **Circuit Breaker**: Fault tolerance for downstream services
/// - **Load Balancer**: Distribution of requests across instances
///
/// ## Expected Behavior
///
/// - Service mesh is created successfully
/// - All component accessors return valid references
/// - The mesh is ready for service registration
fn test_service_mesh_new() {
    let config = RiServiceMeshConfig::default();
    
    // Create service mesh with default configuration
    let service_mesh = RiServiceMesh::new(config).unwrap();
    
    // Verify all components are accessible
    let _ = service_mesh.get_service_discovery();
    let _ = service_mesh.get_health_checker();
    let _ = service_mesh.get_traffic_manager();
    let _ = service_mesh.get_circuit_breaker();
    let _ = service_mesh.get_load_balancer();
}

#[tokio::test]
/// Tests service registration in the service mesh.
///
/// Verifies that services can be registered with the mesh and that
/// registered services can be discovered by other services.
///
/// ## Registration Process
///
/// 1. Service calls register_service() with name, endpoint, and weight
/// 2. Service mesh creates a service instance in the registry
/// 3. New services start in an unknown health state
/// 4. Health checker will verify the service before adding to discovery
///
/// ## Discovery Behavior
///
/// - Unhealthy services are not returned by discovery
/// - Services must pass health checks to receive traffic
/// - Discovery returns an error if no healthy instances exist
///
/// ## Expected Behavior
///
/// - Service is registered successfully
/// - Discovery returns error for unregistered service
/// - Service is available for health updates
async fn test_service_mesh_register_service() {
    let config = RiServiceMeshConfig::default();
    let service_mesh = RiServiceMesh::new(config).unwrap();
    
    // Test registering a service
    let service_name = "test_service";
    let endpoint = "http://localhost:8080";
    let weight = 100;
    
    // Register the service
    service_mesh.register_service(service_name, endpoint, weight).await.unwrap();
    
    // Test discovering the service
    let endpoints = service_mesh.discover_service(service_name).await;
    
    // Should return an error because the service is not healthy yet
    assert!(endpoints.is_err());
}

#[tokio::test]
/// Tests health status updates for registered services.
///
/// Verifies that service health can be updated and that discovery
/// respects the health status when returning service endpoints.
///
/// ## Health Status Flow
///
/// 1. Services start in Unknown state after registration
/// 2. update_service_health() transitions to Healthy or Unhealthy
/// 3. Healthy services are returned by discovery
/// 4. Unhealthy services are excluded from discovery
///
/// ## Expected Behavior
///
/// - Healthy service is returned by discovery
/// - Unhealthy service is excluded from discovery
/// - Health updates are persisted in the registry
async fn test_service_mesh_update_service_health() {
    let config = RiServiceMeshConfig::default();
    let service_mesh = RiServiceMesh::new(config).unwrap();
    
    // Register a service
    let service_name = "test_service";
    let endpoint = "http://localhost:8080";
    let weight = 100;
    
    service_mesh.register_service(service_name, endpoint, weight).await.unwrap();
    
    // Update service health to healthy
    service_mesh.update_service_health(service_name, endpoint, true).await.unwrap();
    
    // Discover the service
    let endpoints = service_mesh.discover_service(service_name).await;
    
    // Should return the service now that it's healthy
    assert!(endpoints.is_ok());
    assert_eq!(endpoints.unwrap().len(), 1);
    
    // Update service health to unhealthy
    service_mesh.update_service_health(service_name, endpoint, false).await.unwrap();
    
    // Discover the service again
    let endpoints = service_mesh.discover_service(service_name).await;
    
    // Should return an error because the service is unhealthy
    assert!(endpoints.is_err());
}

#[test]
/// Tests RiServiceInstance creation and field access.
///
/// Verifies that service instances can be created with all required
/// properties for identification, networking, and status tracking.
///
/// ## Service Instance Properties
///
/// - **id**: Unique identifier for the instance
/// - **service_name**: Name of the service this instance belongs to
/// - **host**: Network hostname or IP address
/// - **port**: Network port number
/// - **status**: Current service status (Running, Stopped, Unknown)
/// - **metadata**: Additional instance metadata as key-value pairs
/// - **registered_at**: Timestamp when instance was registered
/// - **last_heartbeat**: Timestamp of last heartbeat received
///
/// ## Expected Behavior
///
/// - All properties are stored correctly
/// - Status matches the configured value
/// - The instance is ready for registration
fn test_service_instance_new() {
    let instance = RiServiceInstance {
        id: "test_instance".to_string(),
        service_name: "test_service".to_string(),
        host: "localhost".to_string(),
        port: 8080,
        status: RiServiceStatus::Running,
        metadata: std::collections::HashMap::new(),
        registered_at: std::time::SystemTime::now(),
        last_heartbeat: std::time::SystemTime::now(),
    };
    
    // Verify identification properties
    assert_eq!(instance.id, "test_instance");
    assert_eq!(instance.service_name, "test_service");
    
    // Verify networking properties
    assert_eq!(instance.host, "localhost");
    assert_eq!(instance.port, 8080);
    
    // Verify status
    assert_eq!(instance.status, RiServiceStatus::Running);
}

#[test]
/// Tests RiHealthCheckResult creation and field access.
///
/// Verifies that health check results capture all relevant information
/// for service health assessment and monitoring.
///
/// ## Health Check Result Properties
///
/// - **service_name**: Name of the service being checked
/// - **endpoint**: URL or address of the health check endpoint
/// - **is_healthy**: Boolean indicating service health
/// - **status_code**: HTTP status code if applicable
/// - **response_time**: Duration of the health check request
/// - **error_message**: Error description if check failed
/// - **timestamp**: When the check was performed
///
/// ## Expected Behavior
///
/// - All properties are captured correctly
/// - Response time is measured accurately
/// - Error information is preserved when check fails
fn test_health_check_result_new() {
    let result = RiHealthCheckResult {
        service_name: "test_service".to_string(),
        endpoint: "http://localhost:8080/health".to_string(),
        is_healthy: true,
        status_code: Some(200),
        response_time: std::time::Duration::from_millis(100),
        error_message: None,
        timestamp: std::time::SystemTime::now(),
    };

    // Verify basic properties
    assert_eq!(result.service_name, "test_service");
    assert_eq!(result.endpoint, "http://localhost:8080/health");
    assert_eq!(result.is_healthy, true);
    
    // Verify HTTP response details
    assert_eq!(result.status_code, Some(200));
    assert_eq!(result.response_time, std::time::Duration::from_millis(100));
}

#[test]
/// Tests RiHealthSummary aggregation and statistics.
///
/// Verifies that health check summaries correctly aggregate
/// results from multiple checks with calculated statistics.
///
/// ## Health Summary Metrics
///
/// - **total_checks**: Total number of health checks performed
/// - **healthy_checks**: Number of checks that passed
/// - **unhealthy_checks**: Number of checks that failed
/// - **success_rate**: Percentage of successful checks (healthy/total)
/// - **average_response_time**: Mean response time across checks
/// - **last_check_time**: Timestamp of most recent check
/// - **overall_status**: Aggregated health status
///
/// ## Success Rate Calculation
///
/// success_rate = (healthy_checks / total_checks) * 100
///
/// ## Expected Behavior
///
/// - All metrics are calculated correctly
/// - Success rate reflects actual pass/fail ratio
/// - Response time is averaged correctly
fn test_health_summary_new() {
    let summary = RiHealthSummary {
        service_name: "test_service".to_string(),
        total_checks: 20,
        healthy_checks: 16,
        unhealthy_checks: 4,
        success_rate: 80.0,
        average_response_time: std::time::Duration::from_millis(100),
        last_check_time: Some(std::time::SystemTime::now()),
        overall_status: RiHealthStatus::Healthy,
    };
    
    // Verify counts
    assert_eq!(summary.total_checks, 20);
    assert_eq!(summary.healthy_checks, 16);
    assert_eq!(summary.unhealthy_checks, 4);
    
    // Verify calculated rate
    assert_eq!(summary.success_rate, 80.0);
}

#[test]
/// Tests RiTrafficRoute creation with match criteria and actions.
///
/// Verifies that traffic routes can be configured with sophisticated
/// routing logic including match criteria, weighted destinations,
/// and resilience policies.
///
/// ## Route Configuration Properties
///
/// - **name**: Unique name for the route
/// - **source_service**: Service initiating the traffic
/// - **destination_service**: Target service for routing
/// - **match_criteria**: Rules for matching requests (path, headers, method)
/// - **route_action**: Action to take (route to destinations)
/// - **retry_policy**: Automatic retry configuration
/// - **timeout**: Request timeout duration
/// - **fault_injection**: Configuration for chaos testing
///
/// ## Match Criteria Types
///
/// - **path_prefix**: Match requests by path prefix
/// - **headers**: Match by HTTP header values
/// - **method**: Match by HTTP method
/// - **query_parameters**: Match by query string values
///
/// ## Expected Behavior
///
/// - All route properties are stored correctly
/// - Match criteria are properly configured
/// - Weighted destinations are preserved
fn test_traffic_route_new() {
    // Define match criteria for routing decisions
    let match_criteria = RiMatchCriteria {
        path_prefix: Some("/api/v1/".to_string()),
        headers: std::collections::HashMap::new(),
        method: Some("GET".to_string()),
        query_parameters: std::collections::HashMap::new(),
    };
    
    // Define weighted destinations for traffic splitting
    let weighted_destinations = vec![
        ri::service_mesh::RiWeightedDestination {        
            service: "backend_service".to_string(),
            weight: 100,
            subset: None,
        },
    ];
    
    // Define the routing action
    let route_action = RiRouteAction::Route(weighted_destinations);
    
    // Create the traffic route
    let route = RiTrafficRoute {
        name: "test_route".to_string(),
        source_service: "frontend_service".to_string(),
        destination_service: "backend_service".to_string(),
        match_criteria,
        route_action,
        retry_policy: None,
        timeout: Some(std::time::Duration::from_secs(30)),
        fault_injection: None,
    };

    // Verify route properties
    assert_eq!(route.name, "test_route");
    assert_eq!(route.source_service, "frontend_service");
    assert_eq!(route.destination_service, "backend_service");
}

#[test]
/// Tests RiServiceHealthStatus enum variants and formatting.
///
/// Verifies that all health status variants exist and can be
/// correctly formatted for logging and display purposes.
///
/// ## Health Status Variants
///
/// - **Healthy**: Service is operating normally and passing health checks
/// - **Unhealthy**: Service has failed health checks and is not receiving traffic
/// - **Unknown**: Initial state before any health checks have been performed
///
/// ## Expected Behavior
///
/// Each status variant has a correct Debug representation that
/// can be used for logging and user interface display.
fn test_service_health_status() {
    // Test all health status variants
    assert_eq!(format!("{:?}", RiServiceHealthStatus::Healthy), "Healthy");
    assert_eq!(format!("{:?}", RiServiceHealthStatus::Unhealthy), "Unhealthy");
    assert_eq!(format!("{:?}", RiServiceHealthStatus::Unknown), "Unknown");
}