Add an assertion to the test

Author: ratmice

lrpar/cttests/src/lib.rs

@@ -332,13 +332,14 @@ fn test_grmtools_section_files() {
     let out_dir = env::var("OUT_DIR").unwrap();
     let cttests_l_glob = format!("{out_dir}/*.l");
     let cttests_y_glob = format!("{out_dir}/*.y");
-
-    for file_path in glob(&examples_l_glob)
+    let files = glob(&examples_l_glob)
         .unwrap()
         .chain(glob(&examples_y_glob).unwrap())
         .chain(glob(&cttests_l_glob).unwrap())
         .chain(glob(&cttests_y_glob).unwrap())
-    {
+        .collect::<Vec<_>>();
+    assert!(!files.is_empty());
+    for file_path in files {
         let file_path = file_path.unwrap();
         let mut s = String::new();
         let mut f = File::open(&file_path).unwrap();