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Flight-like Flight S/W Testing Methods

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Flight-like Flight S/W Testing Methods

  1. 1. Flight-like Flight Software Testing Methods Celina A Garcia Jet Propulsion Laboratory California Institute of Technology ©2009 California Institute of Technology. Government sponsorship acknowledged.
  2. 2. Introduction <ul><li>Flight Software (FSW) testing methods used by Mars Science Laboratory (MSL) </li></ul><ul><ul><li>Not a new concept, many contributors </li></ul></ul><ul><li>What is “flight-like” testing? </li></ul><ul><ul><li>Same means & methods used in Mission Operations </li></ul></ul><ul><ul><li>Use flight scenarios similar to those defined by Systems to test FSW </li></ul></ul>Celina A Garcia, Nov 2009, Flight-like FSW Testing Methods 11/5/2009
  3. 3. Previous FSW Test Methods <ul><li>Past experience with FSW test methods </li></ul><ul><ul><li>FSW Developer: white box testing </li></ul></ul><ul><ul><li>FSW Build & Integration: minimal gray box testing </li></ul></ul><ul><ul><li>Systems Engineering: black box testing </li></ul></ul><ul><li>Normal S/W development, the schedule can absorb any changes due to design flaws </li></ul><ul><li>Tight S/W schedules can’t afford to catch design flaws during Systems Eng. & ATLO (Assembly Test & Launch Ops) testing. </li></ul>Celina A Garcia, Nov 2009, Flight-like FSW Testing Methods 11/5/2009
  4. 4. Issue <ul><li>FSW schedule is impacted </li></ul><ul><ul><li>Very tight schedule </li></ul></ul><ul><ul><li>Unscheduled point releases due to problems found during systems tests </li></ul></ul><ul><li>Causes: </li></ul><ul><ul><li>FSW team testing did not necessarily include sending commands and verifying telemetry </li></ul></ul><ul><ul><li>Dynamic design and/or poor interpretation of requirements & functionality </li></ul></ul>Celina A Garcia, Nov 2009, Flight-like FSW Testing Methods 11/5/2009
  5. 5. Solution <ul><li>Formation of MSL FSW internal test (FIT) team </li></ul><ul><ul><li>Objective: Use gray box testing approach to discover FSW problems before Systems Eng. testing does </li></ul></ul><ul><ul><li>Employ same interfaces to S/C as Systems Eng. </li></ul></ul><ul><ul><li>Use FSW knowledge to test & stress FSW in ways Systems Eng. may not </li></ul></ul><ul><ul><ul><li>FSW Event Reporting throttling </li></ul></ul></ul><ul><ul><ul><li>Stressing uplink & downlink </li></ul></ul></ul><ul><li>Results in fewer point builds & ensures a more stable FSW product </li></ul>Celina A Garcia, Nov 2009, Flight-like FSW Testing Methods 11/5/2009
  6. 6. FIT Approach <ul><li>Gray box testing </li></ul><ul><ul><li>“ Test as you fly and fly as you test” </li></ul></ul><ul><ul><li>Mix of black & white box testing </li></ul></ul><ul><ul><li>Going beyond traditional unit testing </li></ul></ul><ul><ul><li>Testing against FSW requirements & functionality described in Functional Description Documents </li></ul></ul><ul><ul><li>Ensure that FSW works how Systems Eng. expects it to work </li></ul></ul><ul><ul><li>Make use of Ground S/W tools </li></ul></ul><ul><ul><ul><li>scripting interface </li></ul></ul></ul>11/5/2009 Celina A Garcia, Nov 2009, Flight-like FSW Testing Methods
  7. 7. FIT Approach (cont.) <ul><ul><li>Test using same venues as Systems Eng. </li></ul></ul><ul><ul><ul><li>Workstation Testset (WSTS) </li></ul></ul></ul><ul><ul><ul><ul><li>simulated avionics with closed loop simulation for Attitude Control Sys. & Entry, Descent, & Landing </li></ul></ul></ul></ul><ul><ul><ul><li>Testbed </li></ul></ul></ul><ul><ul><ul><ul><li>combination of simulated and real avionics with closed loop simulation as well </li></ul></ul></ul></ul>11/5/2009 Celina A Garcia, Nov 2009, Flight-like FSW Testing Methods
  8. 8. Flight-like FSW Testing Process <ul><li>FIT testers create functional tests by: </li></ul><ul><ul><li>Reviewing Functional Description Documents (FDDs) and FSW design docs </li></ul></ul><ul><ul><li>Consulting FSW developer and Systems Engineer </li></ul></ul><ul><ul><li>Test script design & test results are reviewed & approved </li></ul></ul><ul><ul><li>Testing done using Workstation Simulation Testset and/or Testbed </li></ul></ul>Celina A Garcia, Nov 2009, Flight-like FSW Testing Methods 11/5/2009
  9. 9. Initial Results <ul><li>In progress </li></ul><ul><li>Short term benefits: </li></ul><ul><ul><li>FSW integration is an easier task near code freeze and release </li></ul></ul><ul><ul><li>FSW has access to the FIT test suite </li></ul></ul><ul><ul><li>FIT can act as a liaison between Systems, Ground S/W and FSW developer </li></ul></ul><ul><ul><li>Provide early feedback to Ground & Simulation S/W </li></ul></ul><ul><ul><li>Functional tests become means for regression testing </li></ul></ul>Celina A Garcia, Nov 2009, Flight-like FSW Testing Methods 11/5/2009
  10. 10. Contact Info <ul><li>E-mail: [email_address] </li></ul><ul><li>MSL FSW Build & Integration Lead & FIT team member </li></ul>Celina A Garcia, Nov 2009, Flight-like FSW Testing Methods 11/5/2009

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