Add test Directory and test_config.rs

tests/test_config.rs

@@ -0,0 +1,20 @@
+use helius_rust_sdk::config::Config;
+use helius_rust_sdk::types::Cluster;
+use helius_rust_sdk::error::HeliusError;
+
+#[test]
+fn test_config_new_with_empty_api_key() {
+    let result: Result<Config, HeliusError> = Config::new("", Cluster::Devnet);
+    assert!(matches!(result, Err(HeliusError::InvalidInput(_))));
+}
+
+#[test]
+fn test_config_new_with_valid_api_key() {
+    let result: Result<Config, HeliusError> = Config::new("valid-api-key", Cluster::Devnet);
+    assert!(result.is_ok());
+
+    let config = result.unwrap();
+    assert_eq!(config.api_key, "valid-api-key");
+    assert_eq!(config.endpoints.api, "https://api-devnet.helius-rpc.com");
+    assert_eq!(config.endpoints.rpc, "https://devnet.helius-rpc.com");
+}