diff --git a/pkgs/by-name/nc/ncps/package.nix b/pkgs/by-name/nc/ncps/package.nix
index 32f0c134cfb0..bcb76f454105 100644
--- a/pkgs/by-name/nc/ncps/package.nix
+++ b/pkgs/by-name/nc/ncps/package.nix
@@ -10,6 +10,94 @@
 }:
 
 let
+
+  # Start MinIO before running tests to enable S3 integration tests
+  minioPreCheck = ''
+    echo "🚀 Starting MinIO for S3 integration tests..."
+
+    # Create temporary directories for MinIO data and config
+    export MINIO_DATA_DIR=$(mktemp -d)
+    export HOME=$(mktemp -d)
+
+    # Configure MinIO credentials (must be set before starting MinIO)
+    export MINIO_ROOT_USER=admin
+    export MINIO_ROOT_PASSWORD=password
+    export MINIO_REGION=us-east-1
+
+    # Generate random free ports using python
+    # We bind to port 0, get the assigned port, and close the socket immediately.
+    # In a Nix sandbox, the race condition risk (port being stolen between check and use) is negligible.
+    export MINIO_PORT=$(python3 -c 'import socket; s=socket.socket(); s.bind(("", 0)); print(s.getsockname()[1]); s.close()')
+    export CONSOLE_PORT=$(python3 -c 'import socket; s=socket.socket(); s.bind(("", 0)); print(s.getsockname()[1]); s.close()')
+
+    # Export S3 test environment variables
+    export NCPS_TEST_S3_BUCKET="test-bucket"
+    export NCPS_TEST_S3_ENDPOINT="http://127.0.0.1:$MINIO_PORT"
+    export NCPS_TEST_S3_REGION="us-east-1"
+    export NCPS_TEST_S3_ACCESS_KEY_ID="test-access-key"
+    export NCPS_TEST_S3_SECRET_ACCESS_KEY="test-secret-key"
+
+    # Start MinIO server in background
+    minio server "$MINIO_DATA_DIR" \
+      --address "127.0.0.1:$MINIO_PORT" \
+      --console-address "127.0.0.1:$CONSOLE_PORT" &
+    export MINIO_PID=$!
+
+    # Wait for MinIO to be ready
+    echo "⏳ Waiting for MinIO to be ready..."
+    for i in {1..30}; do
+      if curl -sf "$NCPS_TEST_S3_ENDPOINT/minio/health/live"; then
+        echo "✅ MinIO is ready"
+        break
+      fi
+      if [ $i -eq 30 ]; then
+        echo "❌ MinIO failed to start"
+        kill $MINIO_PID 2>/dev/null || true
+        exit 1
+      fi
+      sleep 1
+    done
+
+    # Setup admin alias
+    mc alias set local "$NCPS_TEST_S3_ENDPOINT" "$MINIO_ROOT_USER" "$MINIO_ROOT_PASSWORD"
+
+    # Create test bucket
+    mc mb "local/$NCPS_TEST_S3_BUCKET" || true
+
+    # Create service account for tests
+    mc admin user svcacct add \
+      --access-key "$NCPS_TEST_S3_ACCESS_KEY_ID" \
+      --secret-key "$NCPS_TEST_S3_SECRET_ACCESS_KEY" \
+      local admin || true
+
+    echo "✅ MinIO configured for S3 integration tests"
+  '';
+
+  # Stop MinIO after tests complete
+  minioPostCheck = ''
+    echo "🛑 Stopping MinIO..."
+    if [ -n "$MINIO_PID" ]; then
+      kill $MINIO_PID 2>/dev/null || true
+      # Wait for MinIO to fully shut down
+      for i in {1..30}; do
+        if ! kill -0 $MINIO_PID 2>/dev/null; then
+          break
+        fi
+        sleep 0.5
+      done
+
+      # If it's still alive, force kill it
+      if kill -0 $MINIO_PID 2>/dev/null; then
+        echo "MinIO did not shut down gracefully, force killing..."
+        kill -9 $MINIO_PID 2>/dev/null || true
+        sleep 1 # Give a moment for the OS to clean up after SIGKILL
+      fi
+    fi
+    sleep 1
+    rm -rf "$MINIO_DATA_DIR" 2>/dev/null || true
+    echo "✅ MinIO stopped and cleaned up"
+  '';
+
   finalAttrs = {
     pname = "ncps";
     version = "0.5.1";
@@ -38,74 +126,15 @@ let
       python3 # used for generating the ports
     ];
 
-    # Start MinIO before running tests to enable S3 integration tests
+    # pre and post checks
     preCheck = ''
-      echo "🚀 Starting MinIO for S3 integration tests..."
+      # Set up cleanup trap to ensure background processes are killed even if tests fail
+      cleanup() {
+        ${minioPostCheck}
+      }
+      trap cleanup EXIT
 
-      # Create temporary directories for MinIO data and config
-      export MINIO_DATA_DIR=$(mktemp -d)
-      export HOME=$(mktemp -d)
-
-      # Configure MinIO credentials (must be set before starting MinIO)
-      export MINIO_ROOT_USER=admin
-      export MINIO_ROOT_PASSWORD=password
-      export MINIO_REGION=us-east-1
-
-      # Generate random free ports using python
-      # We bind to port 0, get the assigned port, and close the socket immediately.
-      # In a Nix sandbox, the race condition risk (port being stolen between check and use) is negligible.
-      export MINIO_PORT=$(python3 -c 'import socket; s=socket.socket(); s.bind(("", 0)); print(s.getsockname()[1]); s.close()')
-      export CONSOLE_PORT=$(python3 -c 'import socket; s=socket.socket(); s.bind(("", 0)); print(s.getsockname()[1]); s.close()')
-
-      # Export S3 test environment variables
-      export NCPS_TEST_S3_BUCKET="test-bucket"
-      export NCPS_TEST_S3_ENDPOINT="http://127.0.0.1:$MINIO_PORT"
-      export NCPS_TEST_S3_REGION="us-east-1"
-      export NCPS_TEST_S3_ACCESS_KEY_ID="test-access-key"
-      export NCPS_TEST_S3_SECRET_ACCESS_KEY="test-secret-key"
-
-      # Start MinIO server in background
-      minio server "$MINIO_DATA_DIR" \
-        --address "127.0.0.1:$MINIO_PORT" \
-        --console-address "127.0.0.1:$CONSOLE_PORT" &
-      export MINIO_PID=$!
-
-      # Wait for MinIO to be ready
-      echo "⏳ Waiting for MinIO to be ready..."
-      for i in {1..30}; do
-        if curl -sf "$NCPS_TEST_S3_ENDPOINT/minio/health/live"; then
-          echo "✅ MinIO is ready"
-          break
-        fi
-        if [ $i -eq 30 ]; then
-          echo "❌ MinIO failed to start"
-          kill $MINIO_PID 2>/dev/null || true
-          exit 1
-        fi
-        sleep 1
-      done
-
-      # Setup admin alias
-      mc alias set local "$NCPS_TEST_S3_ENDPOINT" "$MINIO_ROOT_USER" "$MINIO_ROOT_PASSWORD"
-
-      # Create test bucket
-      mc mb "local/$NCPS_TEST_S3_BUCKET" || true
-
-      # Create service account for tests
-      mc admin user svcacct add \
-        --access-key "$NCPS_TEST_S3_ACCESS_KEY_ID" \
-        --secret-key "$NCPS_TEST_S3_SECRET_ACCESS_KEY" \
-        local admin || true
-
-      echo "✅ MinIO configured for S3 integration tests"
-    '';
-
-    # Stop MinIO after tests complete
-    postCheck = ''
-      echo "🛑 Stopping MinIO..."
-      kill $MINIO_PID 2>/dev/null || true
-      rm -rf "$MINIO_DATA_DIR"
-      echo "✅ MinIO stopped and cleaned up"
+      ${minioPreCheck}
     '';
 
     postInstall = ''