diff --git a/Cargo.lock b/Cargo.lock
index 866d3f80..6c2a08ed 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -75,12 +75,6 @@ version = "0.4.22"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "a7a70ba024b9dc04c27ea2f0c0548feb474ec5c54bba33a7f72f873a39d07b24"
 
-[[package]]
-name = "once_cell"
-version = "1.19.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "3fdb12b2476b595f9358c5161aa467c2438859caa136dec86c26fdd2efe17b92"
-
 [[package]]
 name = "percent-encoding"
 version = "2.3.1"
@@ -185,7 +179,6 @@ dependencies = [
  "hoot",
  "http",
  "log",
- "once_cell",
  "thiserror",
 ]
 
diff --git a/Cargo.toml b/Cargo.toml
index d3de5576..b39adc88 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -27,5 +27,4 @@ features = []
 hoot = { git = "https://github.com/algesten/hoot", rev = "2e2eac5" }
 http = "1.1.0"
 log = "0.4.22"
-once_cell = "1.19.0"
 thiserror = "1.0.61"
diff --git a/src/lib.rs b/src/lib.rs
index bb33218f..08051bb2 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -3,14 +3,12 @@
 // #![cfg_attr(docsrs, feature(doc_cfg, doc_auto_cfg))]
 
 use std::convert::TryFrom;
-use std::sync::atomic::{AtomicBool, Ordering};
 
 use body::AsBody;
 /// Re-exported http-crate.
 pub use http;
 
 use http::{Method, Request, Response, Uri};
-use once_cell::sync::Lazy;
 use recv::RecvBody;
 use request::RequestBuilder;
 
@@ -61,18 +59,12 @@ where
     builder(Method::POST, uri)
 }
 
-// is_test returns false so long as it has only ever been called with false.
-// If it has ever been called with true, it will always return true after that.
-// This is a public but hidden function used to allow doctests to use the test_agent.
-// Note that we use this approach for doctests rather the #[cfg(test)], because
-// doctests are run against a copy of the crate build without cfg(test) set.
-// We also can't use #[cfg(doctest)] to do this, because cfg(doctest) is only set
-// when collecting doctests, not when building the crate.
-#[doc(hidden)]
-pub fn is_test(is: bool) -> bool {
-    static IS_TEST: Lazy<AtomicBool> = Lazy::new(|| AtomicBool::new(false));
-    if is {
-        IS_TEST.store(true, Ordering::SeqCst);
+#[cfg(test)]
+mod test {
+    use super::*;
+
+    #[test]
+    fn simple_get() {
+        get("https://httpbin.org/get").call().unwrap();
     }
-    IS_TEST.load(Ordering::SeqCst)
 }
diff --git a/src/request.rs b/src/request.rs
index 09a4140d..30ec8cff 100644
--- a/src/request.rs
+++ b/src/request.rs
@@ -30,14 +30,11 @@ impl RequestBuilder {
     /// # Examples
     ///
     /// ```
-    /// # fn main() -> Result<(), ureq::Error> {
-    /// # ureq::is_test(true);
     /// let res = ureq::get("https://host.test/my-path")
     ///     .header("Accept", "text/html")
     ///     .header("X-Custom-Foo", "bar")
     ///     .call()?;
-    /// # Ok(())
-    /// # }
+    /// # Ok::<_, ureq::Error>(())
     /// ```
     pub fn header<K, V>(mut self, key: K, value: V) -> RequestBuilder
     where
@@ -56,12 +53,9 @@ impl RequestBuilder {
     /// Content-Length nor Transfer-Encoding.
     ///
     /// ```
-    /// # fn main() -> Result<(), ureq::Error> {
-    /// # ureq::is_test(true);
     /// let resp = ureq::get("http://httpbin.org/get")
     ///     .call()?;
-    /// # Ok(())
-    /// # }
+    /// # Ok::<_, ureq::Error>(())
     /// ```
     pub fn call(self) -> Result<Response<RecvBody>, Error> {
         let request = self.builder.body(()).unwrap();
@@ -73,12 +67,9 @@ impl RequestBuilder {
     /// The `Content-Length` header is implicitly set to the length of the serialized value.
     ///
     /// ```
-    /// # fn main() -> Result<(), ureq::Error> {
-    /// # ureq::is_test(true);
     /// let resp = ureq::post("http://httpbin.org/put")
     ///     .send_bytes(&[0; 1000])?;
-    /// # Ok(())
-    /// # }
+    /// # Ok::<_, ureq::Error>(())
     /// ```
     pub fn send_bytes(self, data: &[u8]) -> Result<Response<RecvBody>, Error> {
         let request = self.builder.body(()).unwrap();