diff --git a/tests/functional/common/vars-and-functions.sh.in b/tests/functional/common/vars-and-functions.sh.in
index 8fef29f97..f86b44242 100644
--- a/tests/functional/common/vars-and-functions.sh.in
+++ b/tests/functional/common/vars-and-functions.sh.in
@@ -73,7 +73,7 @@ clearProfiles() {
 
 clearStore() {
     echo "clearing store..."
-    chmod -R +w "$NIX_STORE_DIR"
+    chmod -R +w "$NIX_STORE_DIR" || true
     rm -rf "$NIX_STORE_DIR"
     mkdir "$NIX_STORE_DIR"
     rm -rf "$NIX_STATE_DIR"
@@ -89,6 +89,15 @@ clearCacheCache() {
     rm -f $TEST_HOME/.cache/nix/binary-cache*
 }
 
+declare -A trapFunctions
+
+callTraps() {
+    for f in "${trapFunctions[@]}"; do
+        $f
+    done
+}
+trap callTraps EXIT
+
 startDaemon() {
     # Don’t start the daemon twice, as this would just make it loop indefinitely
     if [[ "${_NIX_TEST_DAEMON_PID-}" != '' ]]; then
@@ -110,6 +119,7 @@ startDaemon() {
       fail "Didn’t manage to start the daemon"
     fi
     trap "killDaemon" EXIT
+    trapFunctions[killDaemon]=killDaemon
     # Save for if daemon is killed
     NIX_REMOTE_OLD=$NIX_REMOTE
     export NIX_REMOTE=daemon
@@ -132,7 +142,7 @@ killDaemon() {
     unset _NIX_TEST_DAEMON_PID
     # Restore old nix remote
     NIX_REMOTE=$NIX_REMOTE_OLD
-    trap "" EXIT
+    trapFunctions[killDaemon]=:
 }
 
 restartDaemon() {
diff --git a/tests/functional/gc-external-daemon/common.sh b/tests/functional/gc-external-daemon/common.sh
new file mode 100644
index 000000000..2bff94788
--- /dev/null
+++ b/tests/functional/gc-external-daemon/common.sh
@@ -0,0 +1,6 @@
+source ../common.sh
+
+enableFeatures "external-gc-daemon"
+echo "gc-socket-path = $NIX_GC_SOCKET_PATH" >> "$NIX_CONF_DIR"/nix.conf
+
+startGcDaemon
diff --git a/tests/functional/gc-external-daemon/gc-auto.sh b/tests/functional/gc-external-daemon/gc-auto.sh
new file mode 100644
index 000000000..1b50c7ed1
--- /dev/null
+++ b/tests/functional/gc-external-daemon/gc-auto.sh
@@ -0,0 +1,5 @@
+source common.sh
+
+cd ..
+source ./gc-auto.sh
+
diff --git a/tests/functional/gc-external-daemon/gc-concurrent.sh b/tests/functional/gc-external-daemon/gc-concurrent.sh
new file mode 100644
index 000000000..76b180aac
--- /dev/null
+++ b/tests/functional/gc-external-daemon/gc-concurrent.sh
@@ -0,0 +1,4 @@
+source common.sh
+
+cd ..
+source ./gc-concurrent.sh
diff --git a/tests/functional/gc-external-daemon/gc-runtime.sh b/tests/functional/gc-external-daemon/gc-runtime.sh
new file mode 100644
index 000000000..0fc5d865d
--- /dev/null
+++ b/tests/functional/gc-external-daemon/gc-runtime.sh
@@ -0,0 +1,5 @@
+source common.sh
+
+cd ..
+source ./gc-runtime.sh
+
diff --git a/tests/functional/gc-external-daemon/gc.sh b/tests/functional/gc-external-daemon/gc.sh
new file mode 100644
index 000000000..6d59d68c2
--- /dev/null
+++ b/tests/functional/gc-external-daemon/gc.sh
@@ -0,0 +1,4 @@
+source common.sh
+
+cd ..
+source ./gc.sh
diff --git a/tests/functional/local.mk b/tests/functional/local.mk
index 18eb887cd..f838e89fd 100644
--- a/tests/functional/local.mk
+++ b/tests/functional/local.mk
@@ -18,6 +18,7 @@ nix_tests = \
   flakes/flake-in-submodule.sh \
   gc.sh \
   nix-collect-garbage-d.sh \
+  gc-external-daemon.sh \
   remote-store.sh \
   legacy-ssh-store.sh \
   lang.sh \
diff --git a/tests/gc-external-daemon.sh b/tests/gc-external-daemon.sh
new file mode 100644
index 000000000..d0eff3892
--- /dev/null
+++ b/tests/gc-external-daemon.sh
@@ -0,0 +1,39 @@
+source common.sh
+
+enableFeatures "external-gc-daemon"
+
+export NIX_GC_SOCKET_PATH=$TEST_ROOT/gc.socket
+startGcDaemon() {
+    # Start the daemon, wait for the socket to appear.  !!!
+    # ‘nix-daemon’ should have an option to fork into the background.
+    rm -f $NIX_GC_SOCKET_PATH
+    $(dirname $(command -v nix))/../libexec/nix/nix-find-roots \
+        -l "$NIX_GC_SOCKET_PATH" \
+        -d "$NIX_STATE_DIR" \
+        -s "$NIX_STORE_DIR" \
+            &
+    for ((i = 0; i < 30; i++)); do
+        if [[ -S $NIX_GC_SOCKET_PATH ]]; then break; fi
+        sleep 1
+    done
+    pidGcDaemon=$!
+    trapFunctions[killGcDaemon]=killGcDaemon
+}
+
+killGcDaemon() {
+    kill $pidGcDaemon
+    for i in {0..10}; do
+        kill -0 $pidGcDaemon || break
+        sleep 1
+    done
+    kill -9 $pidGcDaemon || true
+    wait $pidGcDaemon || true
+    trapFunctions[killGcDaemon]=:
+}
+
+startGcDaemon
+
+source ./gc.sh
+source ./gc-concurrent.sh
+source ./gc-runtime.sh
+source ./gc-auto.sh