The Antibiotics of Software Engineering - Agile Testing

Surgery is not a recent invention, it dates back millennia. 

Notable Milestones in Surgical History (http://surgery.about.com/od/surgeryinthemedia/a/HistoryOfSurgeryTimeline.htm)

6,500 B.C.E. - Skulls found in France show signs of a rudimentary surgery called trepanation, which involves drilling a hole in the skull.

1540 C.E. - English barbers and surgeons unite to form The United Barber-Surgeons Company. These barber-surgeons performed tooth extractions and blood letting. Physicians were considered an entirely different profession, treating illness with medications.

1818 - First transfusion of human blood.

1843 - First hysterectomy performed, in England.

1843 - First use of ether.

1867 - British surgeon Joseph Lister publishes Antiseptic Principle in the Practice of Surgery, extolling the virtues of cleanliness in surgery. The mortality rate for surgical patients immediately falls.

1885 - First successful appendectomy performed, in Iowa.

1890s - Widespread use of chemical agents to minimize germs. Carbolic acid was put on incisions to minimize germs and decrease infection rates.

1896 - First successful heart surgery performed, in Germany. Surgeons repaired a stab wound in the muscle of the right ventricle.

1905 - First successful cornea transplant.

1917 - First documented plastic surgery performed, on a burned English sailor.

1928 - Antibiotics discovered.

…

Even if the procedure was successful, often the patient suffered and usually died of subsequent infections. 

Also, not to ignore is the discovery of Ingnaz Semmelweis, a physician at a Vienna hospital. While working at a Vienna hospital in 1847 he discovered that far more women died after childbirth by the so called childbed fever in the medical ward then in the midwifes ward. Semmelweis postulated the presence and spreading of germs causing the illness by doctors. Even though, after applying a chlorine and lemon based hand-wash solution the death rate could be reduced from ~35% to 1%, he was being labeled a heretic by the doctors. Ignaz Semmelweis was ignored until Louis Pasteur confirmed the germ theory.

Now, after it was accepted that germs caused infections and that hygiene was mandatory for good outcomes it became also obvious that there was a need to have a treatment once an infection set in. As listed above, on September 3rd  in 1928 Alexendar Flemming discovered the antibiotic effect of Penecillin and transformed medicine as we know it. Nowadays, antibiotics are used to treat all kinds of infections and antibiotics are prescribed in a preventive manner for many medical procedures. 

In software development we are able to develop rather fast and make significant changes to existing systems quickly. However, after these procedures the system often falls sick, suffering from bugs, side-effects and other ailments. I like to consider these as infections. Those infections even arise after well planned and executed engineering efforts.

The fundamental question is, how can we cope with them or even better avoid them - what is the the antibiotic equivalent in programming?

For me, the answer is: Agile Testing

Agile Testing is the process to validate that new functionality performs correctly and more importantly to verify that the existing behavior has not changed - that no infection has set in.

1. We have proof that the current system is healthy before the procedure starts

2. We are able to monitor the systems health during the procedure

3. We can intervene the moment side effects set in

4. We have proof that the procedure was successful 

A well done Agile Testing strategy is the equivalent to clean medical equipment and antibiotics.