diff --git a/eo-runtime/src/test/eo/org/eolang/rust-tests.eo b/eo-runtime/src/test/eo/org/eolang/rust-tests.eo
index 3c4d3aa2b5..3d7bdc101c 100644
--- a/eo-runtime/src/test/eo/org/eolang/rust-tests.eo
+++ b/eo-runtime/src/test/eo/org/eolang/rust-tests.eo
@@ -274,4 +274,6 @@
       [e]
         e > @
       nop
-    $.contains-string "Custom error"
+    $.all-of
+      $.string-starts-with "Rust insert failed "
+      $.string-ends-with "'Custom error'"