From: Stefan Schmiedl Date: 2001-12-03T09:35:23+09:00 Subject: [ruby-talk:27303] Re: Quantitative Unit-testing? (Re: John Roth dolt ( Re: A challenge to proponents of Unit Testing. ) Panu Viljamaa (2001-12-03 08:20): > Ron Jeffries wrote: > > > On Sun, 02 Dec 2001 16:05:40 -0500, Panu Viljamaa > > wrote: >If we start system building from tests first, we could declare > > that the tests *are* the "Specification" of the system. Then the question > > turns into: "How can we know all assumptions other components make about my > > component are expressed by my unit tests?". I.e. how can we know nobody is > > violating the contract/specification expressed by my tests-code? > > > > Their tests run? > > Not necessarily. If all their tests run, it does not mean these tests > exercise my components in all the same ways as the 'real application' will. if they worked "test-first", it does. > > Note that their test cases are explicitly meant to "unit-test" their > component, not *my* component, nor what happens when their component is > integrated with my component. then they are not doing their homework ... because your component might change over time and after some "harmless" upgrade their software might just stop working ... if i use an axe, i make sure that it's head is fixed, because i don't want to lose mine. > > It's a bit like saying: "Its fine with us as long as the airplane flies. We > need not make sure our components are of the highest quality, or even know > how high quality they are. The airplane flies! ". > on the other hand, high quality components don't guarantee that a plane can take off (concorde) or land (mars lander) successfully. i prefer unit-tested software over other software every day. s. -- Stefan Schmiedl EDV-Beratung, Programmierung, Schulung Loreleystr. 5, 94315 Straubing, Germany Tel. (0 94 21) 74 01 06 Public Key: http://xss.de/stefan.public shhhh ... I can't hear my code!