diff --git a/Cargo.toml b/Cargo.toml
index a318dee..b9091f9 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -20,7 +20,6 @@ diff = "0.1.10"
 filetime = "0.2"
 getopts = "0.2"
 log = "0.4"
-once_cell = "1.20"
 regex = "1.0"
 rustfix = "0.8"
 rustversion = "1.0"
diff --git a/src/runtest.rs b/src/runtest.rs
index 69e89f5..e2bba55 100644
--- a/src/runtest.rs
+++ b/src/runtest.rs
@@ -21,7 +21,6 @@ use filetime::FileTime;
 use regex::Regex;
 use rustfix::{apply_suggestions, get_suggestions_from_json, Filter};
 
-use once_cell::sync::Lazy;
 use std::collections::HashMap;
 use std::collections::HashSet;
 use std::env;
@@ -33,20 +32,21 @@ use std::io::{self, BufReader};
 use std::path::{Path, PathBuf};
 use std::process::{Child, Command, ExitStatus, Output, Stdio};
 use std::str;
-use std::sync::{Arc, Mutex, RwLock};
+use std::sync::{Arc, Mutex, OnceLock, RwLock};
 
 use crate::extract_gdb_version;
 
 fn get_or_create_coverage_file(path: &Path, create: impl FnOnce() -> File) -> Arc<Mutex<File>> {
-    static COVERAGE_FILE_LOCKS: Lazy<RwLock<HashMap<PathBuf, Arc<Mutex<File>>>>> =
-        Lazy::new(Default::default);
+    static COVERAGE_FILE_LOCKS: OnceLock<RwLock<HashMap<PathBuf, Arc<Mutex<File>>>>> =
+        OnceLock::new();
 
+    let locks = COVERAGE_FILE_LOCKS.get_or_init(Default::default);
     {
-        let locks = COVERAGE_FILE_LOCKS.read().unwrap();
+        let locks = locks.read().unwrap();
         locks.get(path).map(Arc::clone)
     }
     .unwrap_or_else(|| {
-        let mut locks = COVERAGE_FILE_LOCKS.write().unwrap();
+        let mut locks = locks.write().unwrap();
         locks
             .entry(path.to_path_buf())
             .or_insert_with(|| Arc::new(Mutex::new(create())))
diff --git a/tests/bless.rs b/tests/bless.rs
index 1c161d8..6c057da 100644
--- a/tests/bless.rs
+++ b/tests/bless.rs
@@ -4,7 +4,7 @@ extern crate compiletest_rs as compiletest;
 
 mod test_support;
 use crate::compiletest::Config;
-use crate::test_support::{testsuite, TestsuiteBuilder, GLOBAL_ROOT};
+use crate::test_support::{global_root, testsuite, TestsuiteBuilder};
 
 fn setup(mode: &str) -> (Config, TestsuiteBuilder) {
     let builder = testsuite(mode);
@@ -12,7 +12,7 @@ fn setup(mode: &str) -> (Config, TestsuiteBuilder) {
     let cfg_mode = mode.parse().expect("Invalid mode");
     config.mode = cfg_mode;
     config.src_base = builder.root.clone();
-    config.build_base = GLOBAL_ROOT.join("build_base");
+    config.build_base = global_root().join("build_base");
 
     (config, builder)
 }
diff --git a/tests/test_support/mod.rs b/tests/test_support/mod.rs
index 638f10c..140ca82 100644
--- a/tests/test_support/mod.rs
+++ b/tests/test_support/mod.rs
@@ -2,12 +2,15 @@
 //!
 //! Inspired by cargo's `cargo-test-support` crate:
 //! https://github.com/rust-lang/cargo/tree/master/crates/cargo-test-support
-use once_cell::sync::Lazy;
+
 use std::cell::RefCell;
 use std::env;
 use std::fs;
 use std::path::{Path, PathBuf};
-use std::sync::atomic::{AtomicUsize, Ordering};
+use std::sync::{
+    atomic::{AtomicUsize, Ordering},
+    OnceLock,
+};
 
 static COMPILETEST_INTEGRATION_TEST_DIR: &str = "cit";
 
@@ -15,16 +18,19 @@ thread_local! {
     static TEST_ID: RefCell<Option<usize>> = RefCell::new(None);
 }
 
-pub static GLOBAL_ROOT: Lazy<PathBuf> = Lazy::new(|| {
-    let mut path = env::current_exe().unwrap();
-    path.pop(); // chop off exe name
-    path.pop(); // chop off 'deps' part
-    path.pop(); // chop off 'debug'
-
-    path.push(COMPILETEST_INTEGRATION_TEST_DIR);
-    path.mkdir_p();
-    path
-});
+pub fn global_root() -> &'static Path {
+    static GLOBAL_ROOT: OnceLock<PathBuf> = OnceLock::new();
+    GLOBAL_ROOT.get_or_init(|| {
+        let mut path = env::current_exe().unwrap();
+        path.pop(); // chop off exe name
+        path.pop(); // chop off 'deps' part
+        path.pop(); // chop off 'debug'
+
+        path.push(COMPILETEST_INTEGRATION_TEST_DIR);
+        path.mkdir_p();
+        path
+    })
+}
 
 pub fn testsuite(mode: &str) -> TestsuiteBuilder {
     let builder = TestsuiteBuilder::new(mode);
@@ -42,7 +48,7 @@ impl TestsuiteBuilder {
 
         let id = NEXT_ID.fetch_add(1, Ordering::Relaxed);
         TEST_ID.with(|n| *n.borrow_mut() = Some(id));
-        let root = GLOBAL_ROOT
+        let root = global_root()
             .join(format!("id{}", TEST_ID.with(|n| n.borrow().unwrap())))
             .join(mode);
         root.mkdir_p();