diff --git a/tests/common/mod.rs b/tests/common/mod.rs
new file mode 100644
index 0000000..312609b
--- /dev/null
+++ b/tests/common/mod.rs
@@ -0,0 +1,46 @@
+// This file is part of the shadow-rs package.
+//
+// For the full copyright and license information, please view the LICENSE
+// file that was distributed with this source code.
+
+//! Shared test helpers for shadow-rs integration tests.
+//!
+//! Import with `#[path = "../common/mod.rs"] mod common;` in test files.
+
+/// Skip the test when not running as root (euid != 0).
+///
+/// Returns `true` if the test should be skipped.
+pub fn skip_unless_root() -> bool {
+    !nix::unistd::geteuid().is_root()
+}
+
+/// Create a temp directory with synthetic `/etc/` files for testing.
+///
+/// Returns a `TempDir` — the directory and files are cleaned up on drop.
+pub fn setup_prefix(shadow_content: &str) -> tempfile::TempDir {
+    let dir = tempfile::tempdir().expect("failed to create temp dir");
+    let etc = dir.path().join("etc");
+    std::fs::create_dir_all(&etc).expect("failed to create etc dir");
+    std::fs::write(etc.join("shadow"), shadow_content).expect("failed to write shadow");
+    dir
+}
+
+/// Create a temp directory with passwd, shadow, and group files.
+pub fn setup_full_prefix(
+    passwd_content: &str,
+    shadow_content: &str,
+    group_content: &str,
+) -> tempfile::TempDir {
+    let dir = tempfile::tempdir().expect("failed to create temp dir");
+    let etc = dir.path().join("etc");
+    std::fs::create_dir_all(&etc).expect("failed to create etc dir");
+    std::fs::write(etc.join("passwd"), passwd_content).expect("failed to write passwd");
+    std::fs::write(etc.join("shadow"), shadow_content).expect("failed to write shadow");
+    std::fs::write(etc.join("group"), group_content).expect("failed to write group");
+    dir
+}
+
+/// Read a file from a temp prefix directory.
+pub fn read_file(dir: &tempfile::TempDir, relative: &str) -> String {
+    std::fs::read_to_string(dir.path().join(relative)).expect("failed to read file")
+}
diff --git a/util/generate-completions.sh b/util/generate-completions.sh
new file mode 100755
index 0000000..6687bb1
--- /dev/null
+++ b/util/generate-completions.sh
@@ -0,0 +1,38 @@
+#!/usr/bin/env bash
+# Generate shell completions for all shadow-rs tools.
+#
+# Usage:
+#   ./util/generate-completions.sh bash
+#   ./util/generate-completions.sh zsh
+#   ./util/generate-completions.sh fish
+#
+# For proper clap-based completions, build with clap_complete.
+# This is a minimal placeholder until clap_complete is integrated.
+
+set -euo pipefail
+
+SHELL_TYPE="${1:-bash}"
+TOOLS="passwd pwck useradd userdel usermod chpasswd chage groupadd groupdel groupmod grpck chfn chsh newgrp"
+
+case "$SHELL_TYPE" in
+  bash)
+    for tool in $TOOLS; do
+      echo "complete -W '--help' $tool"
+    done
+    ;;
+  zsh)
+    echo "#compdef shadow-rs"
+    for tool in $TOOLS; do
+      echo "complete -c $tool -s h -l help -d 'Show help'"
+    done
+    ;;
+  fish)
+    for tool in $TOOLS; do
+      echo "complete -c $tool -s h -l help -d 'Show help'"
+    done
+    ;;
+  *)
+    echo "Usage: $0 {bash|zsh|fish}" >&2
+    exit 1
+    ;;
+esac