fix: inline unused cache root helper and drop dead tests

Signed-off-by: Andrew Paprotsky <apaprotskyi@nvidia.com>

Author: andrewpaprotsky

modelexpress_client/src/lib.rs

@@ -227,32 +227,20 @@ impl Client {
         })
     }
 
-    /// Get the cache directory path for the requested provider, using the
-    /// provider's environment overrides first and then falling back to the
-    /// client's configured cache root.
-    fn get_cache_dir(&self, provider: ModelProvider) -> PathBuf {
-        use std::env;
-        if provider == ModelProvider::HuggingFace
-            && let Ok(cache_path) = env::var("HF_HUB_CACHE")
-        {
-            return PathBuf::from(cache_path);
-        }
-
-        if let Some(cache_config) = self.cache_config.as_ref() {
-            return cache_config.local_path.clone();
-        }
-
-        CacheConfig::discover()
-            .map(|config| config.local_path)
-            .unwrap_or_else(|_| CacheConfig::default().local_path)
-    }
-
     pub async fn get_model_path(
         &self,
         model_name: &str,
         provider: ModelProvider,
     ) -> anyhow::Result<PathBuf> {
-        let cache_dir = self.get_cache_dir(provider);
+        let cache_dir = self
+            .cache_config
+            .as_ref()
+            .map(|config| config.local_path.clone())
+            .unwrap_or_else(|| {
+                CacheConfig::discover()
+                    .map(|config| config.local_path)
+                    .unwrap_or_else(|_| CacheConfig::default().local_path)
+            });
         let model_path = download::get_provider(provider)
             .get_model_path(model_name, cache_dir)
             .await
@@ -644,7 +632,6 @@ mod tests {
             FileChunk, ModelDownloadRequest, ModelFileList, ModelFilesRequest, ModelStatusUpdate,
             model_service_server::{ModelService, ModelServiceServer},
         },
-        test_support::{EnvVarGuard, acquire_env_mutex},
     };
     use std::collections::HashMap;
     #[cfg(unix)]
@@ -854,17 +841,6 @@ mod tests {
         ClientConfig::for_testing("http://test-endpoint:1234")
     }
 
-    fn create_test_client(cache_config: Option<CacheConfig>) -> Client {
-        let channel = tonic::transport::Endpoint::from_static("http://127.0.0.1:1").connect_lazy();
-
-        Client {
-            health_client: HealthServiceClient::new(channel.clone()),
-            api_client: ApiServiceClient::new(channel.clone()),
-            model_client: ModelServiceClient::new(channel),
-            cache_config,
-        }
-    }
-
     #[test]
     fn test_client_config_creation() {
         let config = create_test_client_config();
@@ -916,64 +892,6 @@ mod tests {
         );
     }
 
-    #[tokio::test]
-    async fn test_get_cache_dir_for_hf_prefers_hf_hub_cache() {
-        let env_lock = acquire_env_mutex();
-        let hf_cache_dir = TempDir::new().expect("Failed to create HF cache dir");
-        let configured_cache_dir = TempDir::new().expect("Failed to create configured cache dir");
-        let _hf_cache_guard = EnvVarGuard::set(
-            &env_lock,
-            "HF_HUB_CACHE",
-            hf_cache_dir
-                .path()
-                .to_str()
-                .expect("Expected HF cache path"),
-        );
-
-        let cache_config = CacheConfig {
-            local_path: configured_cache_dir.path().to_path_buf(),
-            server_endpoint: "http://localhost:8001".to_string(),
-            timeout_secs: None,
-            shared_storage: true,
-            transfer_chunk_size: modelexpress_common::constants::DEFAULT_TRANSFER_CHUNK_SIZE,
-        };
-        let client = create_test_client(Some(cache_config));
-
-        assert_eq!(
-            client.get_cache_dir(ModelProvider::HuggingFace),
-            hf_cache_dir.path()
-        );
-    }
-
-    #[tokio::test]
-    async fn test_get_cache_dir_for_gcs_uses_configured_cache_dir() {
-        let env_lock = acquire_env_mutex();
-        let hf_cache_dir = TempDir::new().expect("Failed to create HF cache dir");
-        let configured_cache_dir = TempDir::new().expect("Failed to create configured cache dir");
-        let _hf_cache_guard = EnvVarGuard::set(
-            &env_lock,
-            "HF_HUB_CACHE",
-            hf_cache_dir
-                .path()
-                .to_str()
-                .expect("Expected HF cache path"),
-        );
-
-        let cache_config = CacheConfig {
-            local_path: configured_cache_dir.path().to_path_buf(),
-            server_endpoint: "http://localhost:8001".to_string(),
-            timeout_secs: None,
-            shared_storage: true,
-            transfer_chunk_size: modelexpress_common::constants::DEFAULT_TRANSFER_CHUNK_SIZE,
-        };
-        let client = create_test_client(Some(cache_config));
-
-        assert_eq!(
-            client.get_cache_dir(ModelProvider::Gcs),
-            configured_cache_dir.path()
-        );
-    }
-
     // Note: Most client tests require a running server, so they would be integration tests
     // These unit tests focus on the configuration and setup logic