diff --git a/t/lib-parallel-checkout.sh b/t/lib-parallel-checkout.sh
new file mode 100644
index 0000000..f60b22e
--- /dev/null
+++ b/t/lib-parallel-checkout.sh
@@ -0,0 +1,42 @@
+# Helpers for tests invoking parallel-checkout
+
+set_checkout_config () {
+	if test $# -ne 2
+	then
+		BUG "usage: set_checkout_config <workers> <threshold>"
+	fi &&
+
+	test_config_global checkout.workers $1 &&
+	test_config_global checkout.thresholdForParallelism $2
+}
+
+# Run "${@:2}" and check that $1 checkout workers were used
+test_checkout_workers () {
+	if test $# -lt 2
+	then
+		BUG "too few arguments to test_checkout_workers"
+	fi &&
+
+	local expected_workers=$1 &&
+	shift &&
+
+	local trace_file=trace-test-checkout-workers &&
+	rm -f "$trace_file" &&
+	GIT_TRACE2="$(pwd)/$trace_file" "$@" &&
+
+	local workers=$(grep "child_start\[..*\] git checkout--worker" "$trace_file" | wc -l) &&
+	test $workers -eq $expected_workers &&
+	rm "$trace_file"
+}
+
+# Verify that both the working tree and the index were created correctly
+verify_checkout () {
+	if test $# -ne 1
+	then
+		BUG "usage: verify_checkout <repository path>"
+	fi &&
+
+	git -C "$1" diff-index --ignore-submodules=none --exit-code HEAD -- &&
+	git -C "$1" status --porcelain >"$1".status &&
+	test_must_be_empty "$1".status
+}