     
     func testSystemID() {
         
+        XCTAssertEqual(GATTSystemID.uuid, .systemId)
+        
         XCTAssertNil(GATTSystemID(data: Data([])))
         XCTAssertNil(GATTSystemID(data: Data([0xff])))
         XCTAssertNil(GATTSystemID(data: Data([0xff, 0xff])))

            
            let data = Data([0x12, 0x34, 0x56, 0xFF, 0xFE, 0x9A, 0xBC, 0xDE].reversed())
            
            let manufacturerIdentifier: UInt40 = 0xFFFE9ABCDE
            let organizationallyUniqueIdentifier: UInt24 = 0x123456
            

            XCTAssertEqual(characteristic.manufacturerIdentifier, 1099511627775)
            XCTAssertEqual(characteristic.organizationallyUniqueIdentifier, 16777215)
            XCTAssertEqual(characteristic.description, "FFFFFFFFFFFFFFFF")
            XCTAssertEqual(characteristic.rawValue, 0xFFFFFFFFFFFFFFFF)
            XCTAssertEqual(characteristic.hashValue, Int(bitPattern: UInt.max))
            XCTAssertEqual(GATTSystemID(data: data), GATTSystemID(data: data))
        }
    }
