An apparatus having a foil pack defining a device enclosure and a fluid conduit defining a fluid channel. The device enclosure may be configured to hold an energy storage device such as a battery or capacitor. The fluid conduit defines a fluid channel configured to allow a flow from the device enclosure through a test port defined by the fluid conduit. The apparatus is configured to establish a vacuum in the device enclosure when a vacuum is established in the fluid channel (e.g., during leak testing of the device enclosure). A scaffolding within the fluid conduit is configured to configured to resist a collapse of the fluid channel when the vacuum is established in the fluid channel.