diff --git a/assets/tests/ruby/promise_runtime_error.rb b/assets/tests/ruby/promise_runtime_error.rb
index a3bdc78..09f5aa7 100644
--- a/assets/tests/ruby/promise_runtime_error.rb
+++ b/assets/tests/ruby/promise_runtime_error.rb
@@ -1,5 +1,5 @@
 def test_func
   rust_func.and_then lambda { |x|
-    $state['x'] = x
+    print('abc' + 5)
   }
 end
diff --git a/src/runtimes/ruby.rs b/src/runtimes/ruby.rs
index 3d05da3..c27933a 100644
--- a/src/runtimes/ruby.rs
+++ b/src/runtimes/ruby.rs
@@ -368,7 +368,9 @@ impl Runtime for RubyRuntime {
                     .into_iter()
                     .map(|x| ruby.get_inner(x.0).as_value())
                     .collect();
-                let result: magnus::Value = f.funcall("call", args.as_slice()).unwrap();
+                let result: magnus::Value = f.funcall("call", args.as_slice()).map_err(|e| {
+                    ScriptingError::RuntimeError(Box::new(io::Error::other(e.to_string())))
+                })?;
                 Ok(RubyValue::new(result))
             }))
     }