diff --git a/payjoin-ffi/contrib/test.sh b/payjoin-ffi/contrib/test.sh
index 10e4693ba..592404efb 100755
--- a/payjoin-ffi/contrib/test.sh
+++ b/payjoin-ffi/contrib/test.sh
@@ -6,10 +6,20 @@ cd "$(dirname "$0")/.."
 cargo test --package payjoin-ffi --verbose --features=_manual-tls,_test-utils
 
 BINDINGS="dart javascript python csharp"
-
+pids=()
 for binding in $BINDINGS; do
     (
         cd "$binding"
         ./contrib/test.sh
-    )
+    ) &
+    pids+=($!)
+done
+
+failed=0
+set +e
+for pid in "${pids[@]}"; do
+    wait "$pid" || failed=1
 done
+set -e
+
+exit $failed
diff --git a/payjoin-ffi/dart/contrib/test.sh b/payjoin-ffi/dart/contrib/test.sh
index 3f5949257..35b3c16bf 100755
--- a/payjoin-ffi/dart/contrib/test.sh
+++ b/payjoin-ffi/dart/contrib/test.sh
@@ -3,6 +3,9 @@ set -euo pipefail
 
 cd "$(dirname "$0")/.."
 
+echo "==> Cleaning nested Cargo.lock..."
+rm -f native/Cargo.lock
+
 echo "==> Generating FFI bindings..."
 bash ./scripts/generate_bindings.sh
 
diff --git a/payjoin-ffi/javascript/contrib/test.sh b/payjoin-ffi/javascript/contrib/test.sh
old mode 100644
new mode 100755