diff --git a/lib/runtime-core-tests/tests/imports.rs b/lib/runtime-core-tests/tests/imports.rs
index bba5050f1..cbdc5a389 100644
--- a/lib/runtime-core-tests/tests/imports.rs
+++ b/lib/runtime-core-tests/tests/imports.rs
@@ -55,7 +55,14 @@ macro_rules! call_and_assert {
     };
 }
 
+/// The shift that is set in the instance memory. The value is part of
+/// the result returned by the imported functions if the memory is
+/// read properly.
 const SHIFT: i32 = 10;
+
+/// The shift that is captured in the environment of a closure. The
+/// value is part of the result returned by the imported function if
+/// the closure captures its environment properly.
 const shift: i32 = 100;
 
 fn imported_functions_forms(test: &dyn Fn(&Instance)) {