Structures and techniques for restraining devices for testing. Test sockets may retain devices under test using one or more retention members protruding from sidewalls of the test sockets. Retained devices may be oriented such that contact arms may traverse horizontally to access the devices to, for example, provide desired testing environments. Devices may be retained by forces applied by the retention members to the retained devices in response to displacement, such as compression or deformation, of the retention members caused by the retained devices. Retention of the devices may be achieved without the need for additional fasteners, claims, or adjustment.