test(rte): add compile_error when the render-template-engine is missing

- so that the error messages when the render-template-engine feature is
  not enabled is more clear

1 files changed, 2 insertions, 0 deletions

diff --git a/tests/rte/main.rs b/tests/rte/main.rs
index a3bcb77..367154e 100644
--- a/tests/rte/main.rs
+++ b/tests/rte/main.rs
@@ -1,6 +1,8 @@
 extern crate mail_codec_composition as compos;
 extern crate mail_codec as mail;
 
+#[cfg(not(feature="render-template-engine"))]
+compile_error!("need feature \"render_template_engine\" to run tests");
 
 use std::path::Path;