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> I was watching some anime last night where the characters were trying to make a computer game for some contest. They finished it, but it was too buggy to play

> I was watching some anime last night where the characters were trying to make a computer game for some contest. They finished it, but it was too buggy to play through to the end without crashing (or causing the computer to restart, not sure how they managed that one), and they decided it would be impossible to fix them all because the game takes five hours to play through all the way. I don't disagree that tests (especially fuzz tests) are essential, but this is a problem with dynamic and unsafe (unrestricted side-effects) languages, not languages in general. You're very unlikely to write a program in a language like Haskell, have the program compile, and then not work as expected.

jrockway 13y ago
Not true at all. Consider this implementation of a function that checks if a string is a palindrome: is_palindrome :: String -> Bool is_palindrome _ = True You still have to test it.
- thirsteh 13y ago
  My statement that you're unlikely to experience problems if you write something in a language with so many compile-time checks isn't "true at all"? Really? And if you really want to argue about silly examples, we can talk about Agda instead, a language in which even your contrived example wouldn't need any unit tests. I never said that you didn't need tests at all, or that you couldn't deliberately write programs that didn't work. I'm just of the opinion that the heightened focus on unit tests is a symptom of a language that doesn't perform such checks for you automatically. I also very strongly disagree with your insinuation that you need unit tests. Fuzz tests can be much more powerful.
  - jrockway 13y ago
    I've written plenty of production software in statically-typed languages, including Haskell. I write about as many tests for them as I do in other languages. Having also written a lot of Python, I don't find my software dying unexpectedly from AttributeErrors. Instead, it merely produces the wrong answer because the wrong code was in the method. The advantage the compiler brings is the ability to refactor. With tests, you don't know if you've gotten everything. But if you change a method signature in, say, Java; you'll know immediately when you run the compiler. But it doesn't mean your program will produce the right answer, it only means that you're calling the function with the right number of arguments of the right types.
    - thirsteh 13y ago
      You're disagreeing very passionately with points I never made. I literally said "I don't disagree that tests are essential." I followed that up with the statement that programs written in languages with compilers that perform a lot of checks at compile time tend to work as expected, to which you responded with "not true at all," and gave an extremely contrived example of something that "needs to be tested."

jrockway 13y ago

Not true at all. Consider this implementation of a function that checks if a string is a palindrome: is_palindrome :: String -> Bool is_palindrome _ = True You still have to test it.

thirsteh 13y ago
My statement that you're unlikely to experience problems if you write something in a language with so many compile-time checks isn't "true at all"? Really? And if you really want to argue about silly examples, we can talk about Agda instead, a language in which even your contrived example wouldn't need any unit tests. I never said that you didn't need tests at all, or that you couldn't deliberately write programs that didn't work. I'm just of the opinion that the heightened focus on unit tests is a symptom of a language that doesn't perform such checks for you automatically. I also very strongly disagree with your insinuation that you need unit tests. Fuzz tests can be much more powerful.
- jrockway 13y ago
  I've written plenty of production software in statically-typed languages, including Haskell. I write about as many tests for them as I do in other languages. Having also written a lot of Python, I don't find my software dying unexpectedly from AttributeErrors. Instead, it merely produces the wrong answer because the wrong code was in the method. The advantage the compiler brings is the ability to refactor. With tests, you don't know if you've gotten everything. But if you change a method signature in, say, Java; you'll know immediately when you run the compiler. But it doesn't mean your program will produce the right answer, it only means that you're calling the function with the right number of arguments of the right types.
  - thirsteh 13y ago
    You're disagreeing very passionately with points I never made. I literally said "I don't disagree that tests are essential." I followed that up with the statement that programs written in languages with compilers that perform a lot of checks at compile time tend to work as expected, to which you responded with "not true at all," and gave an extremely contrived example of something that "needs to be tested."