diff --git a/event_sidecar/src/event_stream_server/sse_server.rs b/event_sidecar/src/event_stream_server/sse_server.rs
index 75030803..dade84b3 100644
--- a/event_sidecar/src/event_stream_server/sse_server.rs
+++ b/event_sidecar/src/event_stream_server/sse_server.rs
@@ -15,6 +15,10 @@ use futures::{future, Stream, StreamExt};
 use http::StatusCode;
 use hyper::Body;
 #[cfg(test)]
+use once_cell::sync::Lazy;
+#[cfg(test)]
+use regex::Regex;
+#[cfg(test)]
 use serde::Serialize;
 #[cfg(test)]
 use serde_json::Value;
@@ -90,6 +94,12 @@ const SIGNATURES_FILTER: [EventFilter; 2] =
     [EventFilter::ApiVersion, EventFilter::FinalitySignature];
 /// The filter associated with `/events/sidecar` path.
 const SIDECAR_FILTER: [EventFilter; 1] = [EventFilter::SidecarVersion];
+
+#[cfg(test)]
+static ENDS_WITH_ID_REGEX: Lazy<Regex> = Lazy::new(|| Regex::new(r"\nid:\d*$").unwrap());
+#[cfg(test)]
+static STARTS_WITH_REGEX: Lazy<Regex> = Lazy::new(|| Regex::new(r"^data:").unwrap());
+
 /// The "id" field of the events sent on the event stream to clients.
 pub type Id = u32;
 pub type IsLegacyFilter = bool;
@@ -684,7 +694,6 @@ mod tests {
     use super::*;
     use casper_types::{testing::TestRng, TransactionHash};
     use rand::Rng;
-    use regex::Regex;
     use std::iter;
     #[cfg(feature = "additional-metrics")]
     use tokio::sync::mpsc::channel;
@@ -946,9 +955,6 @@ mod tests {
                 ))
                 .collect();
 
-        let ends_with_id = Regex::new(r"\nid:\d*$").unwrap();
-        let starts_with_data = Regex::new(r"^data:").unwrap();
-
         // Run three cases; where only a single event is duplicated, where five are duplicated, and
         // where the whole initial stream (except the `ApiVersion`) is duplicated.
         for duplicate_count in &[1, 5, NUM_INITIAL_EVENTS] {
@@ -1019,12 +1025,12 @@ mod tests {
                 if let Some(id) = deduplicated_event.id {
                     assert!(received_event_str.ends_with(format!("\nid:{}", id).as_str()));
                 } else {
-                    assert!(!ends_with_id.is_match(received_event_str.as_str()));
+                    assert!(!ENDS_WITH_ID_REGEX.is_match(received_event_str.as_str()));
                 };
-                received_event_str = ends_with_id
+                received_event_str = ENDS_WITH_ID_REGEX
                     .replace_all(received_event_str.as_str(), "")
                     .into_owned();
-                received_event_str = starts_with_data
+                received_event_str = STARTS_WITH_REGEX
                     .replace_all(received_event_str.as_str(), "")
                     .into_owned();
                 if is_legacy_endpoint {
diff --git a/rust-toolchain.toml b/rust-toolchain.toml
index 6d4bd803..f02e0fc6 100644
--- a/rust-toolchain.toml
+++ b/rust-toolchain.toml
@@ -2,4 +2,4 @@
 channel = "1.84.0"
 components = [ "rustfmt", "clippy" ]
 targets = [ "wasm32-unknown-unknown" ]
-profile = "minimal"
\ No newline at end of file
+profile = "minimal"