Tracking Code Quality

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Tracking Code Quality

  • Presentation by Marty Andrews
  • The Cyclomatic Complexity of a method is really the minimum number of unit tests needed to test very path in a method.
  • By reducing CC, usually by breaking large methods down, you reduce the number of tests you need to write!
  • Complexian - www.cogentconsulting.com.au/resources/complexian/index.html
  • FindBugs - usually needs human to interpret. Good to hook in but not run in CI. Human can run so often
  • SourceMonitor
  • JOODI - Package level checking. Good to enforce certain layers only access other layers e.g.
  • Spec#
  • Clover2
    • Project Risk Coverage Cloud - A tag cloud containing every class that exposes those which have low test coverage but high cyclomatic complexity
    • Custom Columns - Define your own quality metric by combining any of Clover's built in ones
    • Track code quality over time using historical charts and reports

Industry standard CCN numbers

  • There was some discussion over what is an unacceptably high CCN. I (JerryShea) don't like to see CCN above 20 personally. I have seen this table reproduced in a few places, including this linuxjournal article:
CCN Interpretation
1-10 a simple program, without much risk
11-20 more complex, moderate risk
21-50 complex, high risk
51+ untestable, very high risk

References

  1. T.J. McCabe, "A complexity measure," IEEE Trans. Software Eng. vol. SE2, no 4, pp 308-320, 1976
  2. B.A. Nejmeh, "NPATH: a measure of execution path complexity and its applications," Commun, ACM, vol 31, no 2, pp 188-200, 1988.
  3. Wikipedia:Cyclomatic_complexity
  4. Complexity Analyser for Java, http://www.martyandrews.net/resources/complexian.html
  5. Complexity Analyser for C++, http://gnocchi.sourceforge.net/
  6. Clover2, http://atlassian.com/clover