encapsulate_and_override_demo.cs

/* Problem */

class Thing {

  // testing this will result in expensive calls to event logs and database
  public int dostuff() {
    int result = something();
    EventLogsAndDatabaseLogger.log(1, 2, 3, 4, 5, "message");
    return result;
  }

}

Thing thing = new Thing();
int result = thing.dostuff(); // Makes expensive calls to db && event logs!
assertEqual(1, result);

/* Solution */

class Thing {

  public int dostuff() {
    int result = something();
    log(1, 2, "message");
    return result;
  }

  private void log(int facility, int level, String message) {
    EventLogsAndDatabaseLogger.log(facility, level, message);
  }

}

class TestableThing : Thing {
  private override void log(int facility, int level, String message) {}
}

TestableThing thing = new TestableThing();
int result = thing.dostuff(); // No longer calls out to db or event logs :)
assertEqual(1, result);