refactor: share common drt test functions (#2583)

Co-authored-by: Keiven Chang <keivenchang@users.noreply.github.com>

lib/runtime/src/distributed.rs

@@ -355,3 +355,20 @@ impl DistributedConfig {
         config
     }
 }
+
+#[cfg(test)]
+pub mod test_helpers {
+    //! Common test helper functions for DistributedRuntime tests
+    // TODO: Use in-memory DistributedRuntime for tests instead of full runtime when available.
+
+    /// Helper function to create a DRT instance for tests
+    /// Uses from_current to leverage existing tokio runtime
+    /// Note: Settings are read from environment variables inside DistributedRuntime::from_settings_without_discovery
+    #[cfg(feature = "integration")]
+    pub async fn create_test_drt_async() -> crate::DistributedRuntime {
+        let rt = crate::Runtime::from_current().unwrap();
+        crate::DistributedRuntime::from_settings_without_discovery(rt)
+            .await
+            .unwrap()
+    }
+}

lib/runtime/src/metrics.rs

@@ -578,15 +578,6 @@ mod test_helpers {
     use super::prometheus_names::{nats_client, nats_service};
     use super::*;
 
-    /// Helper function to create a DRT instance for testing in async contexts
-    #[cfg(feature = "integration")]
-    pub async fn create_test_drt_async() -> crate::DistributedRuntime {
-        let rt = crate::Runtime::from_current().unwrap();
-        crate::DistributedRuntime::from_settings_without_discovery(rt)
-            .await
-            .unwrap()
-    }
-
     /// Base function to filter Prometheus output lines based on a predicate.
     /// Returns lines that match the predicate, converted to String.
     fn filter_prometheus_lines<F>(input: &str, mut predicate: F) -> Vec<String>
@@ -822,7 +813,6 @@ mod test_metricsregistry_units {
         println!("✓ Prometheus metric parsing works correctly!");
     }
 
-    #[cfg(feature = "integration")]
     #[test]
     fn test_metrics_registry_entry_callbacks() {
         use crate::MetricsRegistryEntry;
@@ -923,11 +913,12 @@ mod test_metricsregistry_units {
 #[cfg(test)]
 mod test_metricsregistry_prefixes {
     use super::*;
+    use crate::distributed::test_helpers::create_test_drt_async;
     use prometheus::core::Collector;
 
     #[tokio::test]
     async fn test_hierarchical_prefixes_and_parent_hierarchies() {
-        let drt = super::test_helpers::create_test_drt_async().await;
+        let drt = create_test_drt_async().await;
 
         const DRT_NAME: &str = "";
         const NAMESPACE_NAME: &str = "ns901";
@@ -1002,7 +993,7 @@ mod test_metricsregistry_prefixes {
     #[tokio::test]
     async fn test_recursive_namespace() {
         // Create a distributed runtime for testing
-        let drt = super::test_helpers::create_test_drt_async().await;
+        let drt = create_test_drt_async().await;
 
         // Create a deeply chained namespace: ns1.ns2.ns3
         let ns1 = drt.namespace("ns1").unwrap();
@@ -1054,13 +1045,14 @@ mod test_metricsregistry_prometheus_fmt_outputs {
     use super::prometheus_names::{nats_client, nats_service};
     use super::prometheus_names::{COMPONENT_NATS_METRICS, DRT_NATS_METRICS};
     use super::*;
+    use crate::distributed::test_helpers::create_test_drt_async;
     use prometheus::Counter;
     use std::sync::Arc;
 
     #[tokio::test]
     async fn test_prometheusfactory_using_metrics_registry_trait() {
         // Setup real DRT and registry using the test-friendly constructor
-        let drt = super::test_helpers::create_test_drt_async().await;
+        let drt = create_test_drt_async().await;
 
         // Use a simple constant namespace name
         let namespace_name = "ns345";
@@ -1312,13 +1304,14 @@ mod test_metricsregistry_nats {
     use super::prometheus_names::{nats_client, nats_service};
     use super::prometheus_names::{COMPONENT_NATS_METRICS, DRT_NATS_METRICS};
     use super::*;
+    use crate::distributed::test_helpers::create_test_drt_async;
     use crate::pipeline::PushRouter;
     use crate::{DistributedRuntime, Runtime};
     use tokio::time::{sleep, Duration};
     #[tokio::test]
     async fn test_drt_nats_metrics() {
         // Setup real DRT and registry using the test-friendly constructor
-        let drt = super::test_helpers::create_test_drt_async().await;
+        let drt = create_test_drt_async().await;
 
         // Get DRT output which should include NATS client metrics
         let drt_output = drt.prometheus_metrics_fmt().unwrap();
@@ -1382,7 +1375,7 @@ mod test_metricsregistry_nats {
         // the values of the metrics.
 
         // Setup real DRT and registry using the test-friendly constructor
-        let drt = super::test_helpers::create_test_drt_async().await;
+        let drt = create_test_drt_async().await;
 
         // Create a namespace and components from the DRT
         let namespace = drt.namespace("ns789").unwrap();

lib/runtime/src/system_status_server.rs

@@ -15,18 +15,14 @@
 
 use crate::config::HealthStatus;
 use crate::logging::make_request_span;
-use crate::logging::TraceParent;
 use crate::metrics::MetricsRegistry;
 use crate::traits::DistributedRuntimeProvider;
-use axum::{body, http::StatusCode, response::IntoResponse, routing::get, Router};
+use axum::{http::StatusCode, response::IntoResponse, routing::get, Router};
 use serde_json::json;
-use std::collections::HashMap;
-use std::sync::Arc;
-use std::sync::OnceLock;
+use std::sync::{Arc, OnceLock};
 use std::time::Instant;
 use tokio::{net::TcpListener, task::JoinHandle};
 use tokio_util::sync::CancellationToken;
-use tower_http::trace::DefaultMakeSpan;
 use tower_http::trace::TraceLayer;
 
 /// System status server information containing socket address and handle
@@ -296,61 +292,10 @@ async fn metrics_handler(state: Arc<SystemStatusState>) -> impl IntoResponse {
 }
 
 // Regular tests: cargo test system_status_server --lib
-// Integration tests: cargo test system_status_server --lib --features integration
-
-#[cfg(test)]
-/// Helper function to create a DRT instance for basic unit tests
-/// Uses from_current to leverage existing tokio runtime without environment configuration
-async fn create_test_drt_async() -> crate::DistributedRuntime {
-    let rt = crate::Runtime::from_current().unwrap();
-    crate::DistributedRuntime::from_settings_without_discovery(rt)
-        .await
-        .unwrap()
-}
-
-#[cfg(test)]
-/// Helper function to create a DRT instance for integration tests
-/// Uses spawn_blocking to create runtime safely without ownership issues
-/// Enables system status server for integration testing
-/// Note: This function uses environment variables to configure and create the DistributedRuntime.
-async fn create_test_drt_with_settings_async() -> crate::DistributedRuntime {
-    // Create runtime in blocking context where it can be safely dropped
-    let handle = tokio::task::spawn_blocking(|| {
-        // Load configuration from environment/settings
-        let config = crate::config::RuntimeConfig::from_settings().unwrap();
-
-        // Create runtime with the configuration and extract handle
-        let runtime = config.create_runtime().unwrap();
-        let handle = runtime.handle().clone();
-
-        // Runtime will be automatically dropped when it goes out of scope
-        handle
-    })
-    .await
-    .unwrap();
-
-    // Create Runtime using external handle (no ownership)
-    let rt = crate::Runtime::from_handle(handle).unwrap();
-    crate::DistributedRuntime::from_settings_without_discovery(rt)
-        .await
-        .unwrap()
-}
-
 #[cfg(test)]
 mod tests {
     use super::*;
-    use crate::logging::tests::load_log;
-    use crate::metrics::MetricsRegistry;
-    use anyhow::{anyhow, Result};
-    use chrono::{DateTime, Utc};
-    use jsonschema::{Draft, JSONSchema};
-    use rstest::rstest;
-    use serde_json::Value;
-    use std::fs::File;
-    use std::io::{BufRead, BufReader};
-    use std::sync::Arc;
-    use stdio_override::*;
-    use tokio::time::{sleep, Duration};
+    use tokio::time::Duration;
 
     // This is a basic test to verify the HTTP server is working before testing other more complicated tests
     #[tokio::test]
@@ -381,8 +326,19 @@ mod tests {
             "HTTP server should shut down when cancel token is cancelled"
         );
     }
+}
+
+// Integration tests: cargo test system_status_server --lib --features integration
+#[cfg(all(test, feature = "integration"))]
+mod integration_tests {
+    use super::*;
+    use crate::distributed::test_helpers::create_test_drt_async;
+    use crate::metrics::MetricsRegistry;
+    use anyhow::Result;
+    use rstest::rstest;
+    use std::sync::Arc;
+    use tokio::time::Duration;
 
-    #[cfg(feature = "integration")]
     #[tokio::test]
     async fn test_uptime_without_initialization() {
         // Test that uptime returns an error if start time is not initialized
@@ -398,7 +354,6 @@ mod tests {
         .await;
     }
 
-    #[cfg(feature = "integration")]
     #[tokio::test]
     async fn test_runtime_metrics_initialization_and_namespace() {
         // Test that metrics have correct namespace
@@ -439,7 +394,6 @@ mod tests {
         .await;
     }
 
-    #[cfg(feature = "integration")]
     #[tokio::test]
     async fn test_start_time_initialization() {
         // Test that start time can only be initialized once
@@ -516,7 +470,7 @@ mod tests {
                 ("DYN_SYSTEM_LIVE_PATH", custom_live_path),
             ],
             (async || {
-                let drt = Arc::new(create_test_drt_with_settings_async().await);
+                let drt = Arc::new(create_test_drt_async().await);
 
                 // Get system status server info from DRT (instead of manually spawning)
                 let system_info = drt
@@ -575,7 +529,6 @@ mod tests {
     }
 
     #[tokio::test]
-    #[cfg(feature = "integration")]
     async fn test_health_endpoint_tracing() -> Result<()> {
         use std::sync::Arc;
 
@@ -596,7 +549,7 @@ mod tests {
 
                 crate::logging::init();
 
-                let drt = Arc::new(create_test_drt_with_settings_async().await);
+                let drt = Arc::new(create_test_drt_async().await);
 
                 // Get system status server info from DRT (instead of manually spawning)
                 let system_info = drt
@@ -631,7 +584,6 @@ mod tests {
         Ok(())
     }
 
-    #[cfg(feature = "integration")]
     #[tokio::test]
     async fn test_health_endpoint_with_changing_health_status() {
         // Test health endpoint starts in not ready status, then becomes ready
@@ -646,7 +598,7 @@ mod tests {
                 ("DYN_SYSTEM_USE_ENDPOINT_HEALTH_STATUS", Some(ENDPOINT_HEALTH_CONFIG)),
             ],
             async {
-                let drt = Arc::new(create_test_drt_with_settings_async().await);
+                let drt = Arc::new(create_test_drt_async().await);
 
                 // Check if system status server was started
                 let system_info_opt = drt.system_status_server_info();
@@ -745,7 +697,6 @@ mod tests {
         .await;
     }
 
-    #[cfg(feature = "integration")]
     #[tokio::test]
     async fn test_spawn_system_status_server_endpoints() {
         // use reqwest for HTTP requests
@@ -756,7 +707,7 @@ mod tests {
                 ("DYN_SYSTEM_STARTING_HEALTH_STATUS", Some("ready")),
             ],
             async {
-                let drt = Arc::new(create_test_drt_with_settings_async().await);
+                let drt = Arc::new(create_test_drt_async().await);
 
                 // Get system status server info from DRT (instead of manually spawning)
                 let system_info = drt