diff --git a/tests/functional/flakes/meson.build b/tests/functional/flakes/meson.build
index 74ff3d91d..7135329f8 100644
--- a/tests/functional/flakes/meson.build
+++ b/tests/functional/flakes/meson.build
@@ -28,6 +28,7 @@ suites += {
     'commit-lock-file-summary.sh',
     'non-flake-inputs.sh',
     'relative-paths.sh',
+    'relative-paths-lockfile.sh',
     'symlink-paths.sh',
     'debugger.sh'
   ],
diff --git a/tests/functional/flakes/relative-paths-lockfile.sh b/tests/functional/flakes/relative-paths-lockfile.sh
new file mode 100644
index 000000000..d91aedd16
--- /dev/null
+++ b/tests/functional/flakes/relative-paths-lockfile.sh
@@ -0,0 +1,73 @@
+#!/usr/bin/env bash
+
+source ./common.sh
+
+requireGit
+
+# Test a "vendored" subflake dependency. This is a relative path flake
+# which doesn't reference the root flake and has its own lock file.
+#
+# This might occur in a monorepo for example. The root flake.lock is
+# populated from the dependency's flake.lock.
+
+rootFlake="$TEST_ROOT/flake1"
+subflake="$rootFlake/sub"
+depFlakeA="$TEST_ROOT/depFlakeA"
+depFlakeB="$TEST_ROOT/depFlakeB"
+
+rm -rf "$rootFlake"
+mkdir -p "$rootFlake" "$subflake" "$depFlakeA" "$depFlakeB"
+
+cat > "$depFlakeA/flake.nix" <<EOF
+{
+  outputs = { self }: {
+    x = 11;
+  };
+}
+EOF
+
+cat > "$depFlakeB/flake.nix" <<EOF
+{
+  outputs = { self }: {
+    x = 13;
+  };
+}
+EOF
+
+[[ $(nix eval "$depFlakeA#x") = 11 ]]
+[[ $(nix eval "$depFlakeB#x") = 13 ]]
+
+cat > "$subflake/flake.nix" <<EOF
+{
+  inputs.dep.url = "path:$depFlakeA";
+  outputs = { self, dep }: {
+    inherit (dep) x;
+    y = self.x - 1;
+  };
+}
+EOF
+
+cat > "$rootFlake/flake.nix" <<EOF
+{
+  inputs.sub.url = ./sub;
+  outputs = { self, sub }: {
+    x = 2;
+    y = sub.y / self.x;
+  };
+}
+EOF
+
+[[ $(nix eval "$subflake#y") = 10 ]]
+[[ $(nix eval "$rootFlake#y") = 5 ]]
+
+nix flake update --flake "path:$subflake" --override-input dep "$depFlakeB"
+
+[[ $(nix eval "path:$subflake#y") = 12 ]]
+
+# Expect that changes to sub/flake.lock are propagated to the root flake.
+# FIXME: doesn't work at the moment #7730
+[[ $(nix eval "$rootFlake#y") = 6 ]] || true
+
+# This will force refresh flake.lock with changes from sub/flake.lock
+nix flake update --flake "$rootFlake"
+[[ $(nix eval "$rootFlake#y") = 6 ]]