diff --git a/meson.build b/meson.build
index 21a08b3..58e1e8f 100644
--- a/meson.build
+++ b/meson.build
@@ -2,6 +2,7 @@ project(
   'depot',
   version: '0.16.1',
   meson_version: '>=0.60.0',
+  default_options: ['buildtype=release'],
 )
 
 fs = import('fs')
@@ -79,6 +80,8 @@ test(
     cargo.full_path(),
     src_root,
     build_root,
+    cargo_profile,
+    cargo_release ? '1' : '0',
   ],
   suite: ['cargo'],
   timeout: 0,
diff --git a/src/shell_helpers.rs b/src/shell_helpers.rs
index dc03f6f..d0b173a 100644
--- a/src/shell_helpers.rs
+++ b/src/shell_helpers.rs
@@ -21,7 +21,15 @@ pub struct ShellHelpers {
 impl ShellHelpers {
     /// Create helper commands for a given staging tree (`DESTDIR`).
     pub fn new(destdir: &Path) -> Result<Self> {
-        let tempdir = tempfile::tempdir().context("Failed to create shell helper tempdir")?;
+        let helper_root = destdir.join(INTERNAL_DEPOT_DIR).join("helpers");
+        fs::create_dir_all(&helper_root).with_context(|| {
+            format!(
+                "Failed to create shell helper root dir: {}",
+                helper_root.display()
+            )
+        })?;
+        let tempdir =
+            tempfile::tempdir_in(&helper_root).context("Failed to create shell helper tempdir")?;
         let bin_dir = tempdir.path().join("bin");
         fs::create_dir_all(&bin_dir)
             .with_context(|| format!("Failed to create helper bin dir: {}", bin_dir.display()))?;
@@ -241,7 +249,8 @@ printf '%s\n' "$path"
 
 #[cfg(test)]
 mod tests {
-    use super::shell_ident_suffix;
+    use super::{INTERNAL_DEPOT_DIR, ShellHelpers, shell_ident_suffix};
+    use tempfile::tempdir;
 
     #[test]
     fn shell_ident_suffix_normalizes_package_names() {
@@ -250,4 +259,26 @@ mod tests {
         assert_eq!(shell_ident_suffix("3foo"), "_3FOO");
         assert_eq!(shell_ident_suffix("foo.bar+baz"), "FOO_BAR_BAZ");
     }
+
+    #[test]
+    fn shell_helpers_use_destdir_internal_helper_dir() {
+        let destdir = tempdir().unwrap();
+        let helpers = ShellHelpers::new(destdir.path()).unwrap();
+        let mut envs = Vec::new();
+        helpers.apply_to_env_vars(&mut envs);
+
+        let path = envs
+            .iter()
+            .find(|(key, _)| key == "PATH")
+            .map(|(_, value)| value)
+            .unwrap();
+
+        let helper_prefix = destdir
+            .path()
+            .join(INTERNAL_DEPOT_DIR)
+            .join("helpers")
+            .to_string_lossy()
+            .into_owned();
+        assert!(path.starts_with(&helper_prefix));
+    }
 }
diff --git a/tools/meson/cargo-test.sh b/tools/meson/cargo-test.sh
index 1d13200..290e21c 100644
--- a/tools/meson/cargo-test.sh
+++ b/tools/meson/cargo-test.sh
@@ -1,14 +1,16 @@
 #!/bin/sh
 set -eu
 
-if [ "$#" -ne 3 ]; then
-    echo "usage: $0 <cargo> <src_root> <build_root>" >&2
+if [ "$#" -ne 5 ]; then
+    echo "usage: $0 <cargo> <src_root> <build_root> <profile> <release_flag>" >&2
     exit 2
 fi
 
 cargo_bin="$1"
 src_root="$2"
 build_root="$3"
+profile="$4"
+release_flag="$5"
 
 cargo_home="$build_root/cargo-home"
 cargo_target_dir="$build_root/cargo-target"
@@ -18,4 +20,8 @@ mkdir -p "$cargo_home" "$cargo_target_dir"
 export CARGO_HOME="$cargo_home"
 export CARGO_TARGET_DIR="$cargo_target_dir"
 
+if [ "$release_flag" = "1" ]; then
+    exec "$cargo_bin" test --locked --manifest-path "$src_root/Cargo.toml" --profile "$profile"
+fi
+
 exec "$cargo_bin" test --locked --manifest-path "$src_root/Cargo.toml"