diff --git a/services/commtest/Cargo.lock b/services/commtest/Cargo.lock
--- a/services/commtest/Cargo.lock
+++ b/services/commtest/Cargo.lock
@@ -93,6 +93,7 @@
  "bytesize",
  "derive_more",
  "futures",
+ "lazy_static",
  "prost",
  "tokio",
  "tonic",
diff --git a/services/commtest/Cargo.toml b/services/commtest/Cargo.toml
--- a/services/commtest/Cargo.toml
+++ b/services/commtest/Cargo.toml
@@ -11,6 +11,7 @@
 async-stream = "0.3.2"
 derive_more = "0.99.16"
 bytesize = "1.1.0"
+lazy_static = "1.4.0"
 
 [build-dependencies]
 tonic-build = "0.6"
diff --git a/services/commtest/tests/backup_test.rs b/services/commtest/tests/backup_test.rs
--- a/services/commtest/tests/backup_test.rs
+++ b/services/commtest/tests/backup_test.rs
@@ -47,7 +47,7 @@
       Item::new(
         String::new(),
         vec![
-          tools::get_dynamo_db_item_size_limit()
+          *tools::DYNAMO_DB_ITEM_SIZE_LIMIT
             - ByteSize::b(attachments_fill_size / 2).as_u64() as usize,
         ],
         vec!["holder0".to_string(), "holder1".to_string()],
@@ -62,8 +62,8 @@
       Item::new(
         String::new(),
         vec![
-          tools::get_grpc_chunk_size_limit(),
-          tools::get_grpc_chunk_size_limit(),
+          *tools::GRPC_CHUNK_SIZE_LIMIT,
+          *tools::GRPC_CHUNK_SIZE_LIMIT,
         ],
         vec![
           "holder0".to_string(),
diff --git a/services/commtest/tests/blob_test.rs b/services/commtest/tests/blob_test.rs
--- a/services/commtest/tests/blob_test.rs
+++ b/services/commtest/tests/blob_test.rs
@@ -36,8 +36,8 @@
       holder: "test_holder002".to_string(),
       hash: "test_hash002".to_string(),
       chunks_sizes: vec![
-        tools::get_grpc_chunk_size_limit(),
-        tools::get_grpc_chunk_size_limit(),
+        *tools::GRPC_CHUNK_SIZE_LIMIT,
+        *tools::GRPC_CHUNK_SIZE_LIMIT,
         ByteSize::b(10).as_u64() as usize,
       ],
     },
@@ -45,9 +45,9 @@
       holder: "test_holder003".to_string(),
       hash: "test_hash003".to_string(),
       chunks_sizes: vec![
-        tools::get_grpc_chunk_size_limit(),
+        *tools::GRPC_CHUNK_SIZE_LIMIT,
         ByteSize::b(100).as_u64() as usize,
-        tools::get_grpc_chunk_size_limit(),
+        *tools::GRPC_CHUNK_SIZE_LIMIT,
       ],
     },
   ];
diff --git a/services/commtest/tests/lib/tools.rs b/services/commtest/tests/lib/tools.rs
--- a/services/commtest/tests/lib/tools.rs
+++ b/services/commtest/tests/lib/tools.rs
@@ -1,4 +1,5 @@
 use bytesize::ByteSize;
+use lazy_static::lazy_static;
 
 #[allow(dead_code)]
 pub fn generate_nbytes(
@@ -21,16 +22,11 @@
   TonicStatus(tonic::Status),
 }
 
-#[allow(dead_code)]
-pub fn get_dynamo_db_item_size_limit() -> usize {
-  ByteSize::kib(400).as_u64() as usize
-}
-
 pub const GRPC_METADATA_SIZE_BYTES: usize = 5;
 
-#[allow(dead_code)]
-pub fn get_grpc_chunk_size_limit() -> usize {
-  (ByteSize::mib(4).as_u64() as usize) - GRPC_METADATA_SIZE_BYTES
+lazy_static! {
+  pub static ref DYNAMO_DB_ITEM_SIZE_LIMIT: usize = ByteSize::kib(400).as_u64() as usize;
+  pub static ref GRPC_CHUNK_SIZE_LIMIT: usize = (ByteSize::mib(4).as_u64() as usize) - GRPC_METADATA_SIZE_BYTES;
 }
 
 #[allow(dead_code)]