diff --git a/crates/mergify-ci/src/detector.rs b/crates/mergify-ci/src/detector.rs
index ab0830c8..5bb4109b 100644
--- a/crates/mergify-ci/src/detector.rs
+++ b/crates/mergify-ci/src/detector.rs
@@ -144,32 +144,7 @@ fn read_github_event_pull_request_number() -> Result<Option<u64>, CliError> {
 #[cfg(test)]
 mod tests {
     use super::*;
-
-    /// Clear every CI-provider env var the detector inspects, then
-    /// apply the test-specific overrides on top. Without this, a
-    /// test running on a real CI host inherits provider state and
-    /// the detector picks the wrong branch.
-    pub(crate) fn with_ci_env<F: FnOnce() -> R, R>(extra: &[(&str, Option<&str>)], f: F) -> R {
-        let mut vars: Vec<(String, Option<String>)> = [
-            "JENKINS_URL",
-            "GITHUB_ACTIONS",
-            "GITHUB_REPOSITORY",
-            "GITHUB_EVENT_PATH",
-            "CIRCLECI",
-            "CIRCLE_REPOSITORY_URL",
-            "BUILDKITE",
-            "BUILDKITE_REPO",
-            "BUILDKITE_PULL_REQUEST",
-            "GIT_URL",
-        ]
-        .into_iter()
-        .map(|k| (k.to_string(), None))
-        .collect();
-        for (k, v) in extra {
-            vars.push((k.to_string(), v.map(ToString::to_string)));
-        }
-        temp_env::with_vars(vars, f)
-    }
+    use crate::testing::with_ci_env;
 
     #[test]
     fn ci_provider_jenkins_takes_precedence() {
diff --git a/crates/mergify-ci/src/lib.rs b/crates/mergify-ci/src/lib.rs
index b06c9f3e..c197ee7f 100644
--- a/crates/mergify-ci/src/lib.rs
+++ b/crates/mergify-ci/src/lib.rs
@@ -13,3 +13,6 @@ pub mod github_event;
 pub mod queue_info;
 pub mod queue_metadata;
 pub mod scopes_send;
+
+#[cfg(test)]
+mod testing;
diff --git a/crates/mergify-ci/src/scopes_send.rs b/crates/mergify-ci/src/scopes_send.rs
index 52bb3666..bd1b3dd7 100644
--- a/crates/mergify-ci/src/scopes_send.rs
+++ b/crates/mergify-ci/src/scopes_send.rs
@@ -156,58 +156,8 @@ mod tests {
     use wiremock::matchers::path;
 
     use super::*;
-
-    /// Clear every CI-provider env var the resolver inspects, then
-    /// apply the test-specific overrides on top. Without this, a test
-    /// running on a real CI host (Buildkite, Actions, …) inherits
-    /// provider env vars and the new provider-aware resolver picks
-    /// the wrong branch.
-    fn with_ci_env<F: FnOnce() -> R, R>(extra: &[(&str, Option<&str>)], f: F) -> R {
-        let mut vars: Vec<(String, Option<String>)> = [
-            "JENKINS_URL",
-            "GITHUB_ACTIONS",
-            "GITHUB_REPOSITORY",
-            "GITHUB_EVENT_PATH",
-            "CIRCLECI",
-            "CIRCLE_REPOSITORY_URL",
-            "BUILDKITE",
-            "BUILDKITE_REPO",
-            "BUILDKITE_PULL_REQUEST",
-            "GIT_URL",
-        ]
-        .into_iter()
-        .map(|k| (k.to_string(), None))
-        .collect();
-        for (k, v) in extra {
-            vars.push((k.to_string(), v.map(ToString::to_string)));
-        }
-        temp_env::with_vars(vars, f)
-    }
-
-    async fn with_ci_env_async<F: std::future::Future<Output = R>, R>(
-        extra: &[(&str, Option<&str>)],
-        f: F,
-    ) -> R {
-        let mut vars: Vec<(String, Option<String>)> = [
-            "JENKINS_URL",
-            "GITHUB_ACTIONS",
-            "GITHUB_REPOSITORY",
-            "GITHUB_EVENT_PATH",
-            "CIRCLECI",
-            "CIRCLE_REPOSITORY_URL",
-            "BUILDKITE",
-            "BUILDKITE_REPO",
-            "BUILDKITE_PULL_REQUEST",
-            "GIT_URL",
-        ]
-        .into_iter()
-        .map(|k| (k.to_string(), None))
-        .collect();
-        for (k, v) in extra {
-            vars.push((k.to_string(), v.map(ToString::to_string)));
-        }
-        temp_env::async_with_vars(vars, f).await
-    }
+    use crate::testing::with_ci_env;
+    use crate::testing::with_ci_env_async;
 
     #[test]
     fn resolve_repository_prefers_flag_over_env() {
diff --git a/crates/mergify-ci/src/testing.rs b/crates/mergify-ci/src/testing.rs
new file mode 100644
index 00000000..979c2ce7
--- /dev/null
+++ b/crates/mergify-ci/src/testing.rs
@@ -0,0 +1,56 @@
+//! Test-only helpers shared between `detector` and `scopes_send`.
+//!
+//! Both modules test CI-provider-aware code paths and need to scrub
+//! the host's CI env vars before running each case — otherwise a
+//! test running on a real Buildkite/Actions/Circle/Jenkins host
+//! inherits provider state and the detector picks the wrong branch.
+//! Two flavors: a sync `with_ci_env` and an async `with_ci_env_async`
+//! (used by the `#[tokio::test]` cases in `scopes_send`).
+
+use std::future::Future;
+
+/// Env vars the CI-provider detection chain inspects. Clear every
+/// one of them before applying the test-specific overrides, so the
+/// host environment can't leak into the test.
+const CI_ENV_VARS: &[&str] = &[
+    "JENKINS_URL",
+    "GITHUB_ACTIONS",
+    "GITHUB_REPOSITORY",
+    "GITHUB_EVENT_PATH",
+    "CIRCLECI",
+    "CIRCLE_REPOSITORY_URL",
+    "BUILDKITE",
+    "BUILDKITE_REPO",
+    "BUILDKITE_PULL_REQUEST",
+    "GIT_URL",
+];
+
+fn merged_overrides(extra: &[(&str, Option<&str>)]) -> Vec<(String, Option<String>)> {
+    let mut vars: Vec<(String, Option<String>)> = CI_ENV_VARS
+        .iter()
+        .map(|k| ((*k).to_string(), None))
+        .collect();
+    for (k, v) in extra {
+        vars.push(((*k).to_string(), v.map(ToString::to_string)));
+    }
+    vars
+}
+
+/// Run `f` with the CI-provider env vars cleared, plus the
+/// `extra` overrides applied on top.
+pub(crate) fn with_ci_env<F, R>(extra: &[(&str, Option<&str>)], f: F) -> R
+where
+    F: FnOnce() -> R,
+{
+    temp_env::with_vars(merged_overrides(extra), f)
+}
+
+/// Async counterpart to [`with_ci_env`]. Used by `#[tokio::test]`
+/// cases in `scopes_send` — the sync variant can't bridge `.await`
+/// points.
+pub(crate) async fn with_ci_env_async<F, R>(extra: &[(&str, Option<&str>)], f: F) -> R
+where
+    F: Future<Output = R>,
+{
+    temp_env::async_with_vars(merged_overrides(extra), f).await
+}