diff --git a/core/src/utils/mod.rs b/core/src/utils/mod.rs
index 1d0f254075..dc679e85e4 100644
--- a/core/src/utils/mod.rs
+++ b/core/src/utils/mod.rs
@@ -6,6 +6,7 @@
 
 use alloc::borrow::ToOwned;
 use alloc::vec::Vec;
+use alloc::string::String;
 use codec::{Compact, Decode, Encode};
 use derivative::Derivative;
 
@@ -26,6 +27,7 @@ pub use static_type::Static;
 pub use unchecked_extrinsic::UncheckedExtrinsic;
 pub use wrapper_opaque::WrapperKeepOpaque;
 
+
 // Used in codegen
 #[doc(hidden)]
 pub use primitive_types::{H160, H256, H512};
diff --git a/testing/no-std-tests/src/main.rs b/testing/no-std-tests/src/main.rs
index 9b1dd79e60..8f8eace211 100644
--- a/testing/no-std-tests/src/main.rs
+++ b/testing/no-std-tests/src/main.rs
@@ -36,6 +36,7 @@ extern crate alloc;
 // Note: Panics in this function will lead to `Aborted (core dumped)` and a non-zero exit status => suitable for CI tests.
 fn run_tests() {
     subxt_metadata_test();
+    subxt_signer_test();
     subxt_core_test();
 }