5 ms·

It'll be fun to refactor a codebase without unit tests </sarcasm>

jononor 9y ago
As long as there are suitable integration and system tests, this is no problem at all. Bonus if there are defensive assertions as recommended in the paper (design-by-contracts style). Sometimes it is easier to refactor a system without lots of unit-tests, as you need to update/fix lots of tightly coupled tests. What matters is what the system does (as seen from the outside), not how the underlying classes/functions work. They are mostly incidental.
wtetzner 9y ago
Refactoring code usually means you have to refractor unit tests as well, since they are so closely tied to the structure of the code. Integration tests, however, should not have to change, since they are typically run against the external interface to the software, which shouldn't change if you're just doing a refactoring.
- juandazapata 9y ago
  Funny thing. Unit tests force you to think about good code design. Integration tests don't. If you only have integration tests in your system, you'll most likely end up with a big ball of mud. I've seen this so many times in so many real world projects that it hurts.
  - mannykannot 9y ago
    > Funny thing. Unit tests force you to think about good code design. Integration tests don't. They absolutely do, but at higher levels of abstraction, in terms of interfaces, interactions, constraints, obligations and responsibilities. In fact, unit and integration tests make you think about design in essentially the same way.
    - juandazapata 9y ago
      Whatever floats your boat. My experience in large enterprise products is exactly the opposite, but I'm glad it works for you.
  - wtetzner 9y ago
    Except that in my experience, unit tests just end up being a big ball of mud too. And at that point, they don't make refactoring easier, they actually make it harder. Having good integration tests means that you're free to completely re-organize your code, and you can still test that it works as expected. Given that requirements change over time, even a well thought out code structure will likely need to be refactored at some point, and being able to have a test suite that doesn't have to be re-written during a refactoring is extremely valuable. I've also seen code bases become unnecessarily complex because so much thought was put into how to unit test it, that not enough thought was put into writing clear, easy to understand code.
- wmil 9y ago
  Yes, but broken tests at least give you hints about where you need to fix things. It can be hard to find every piece of code that relies on something you're changing.
Const-me 9y ago
Did that many times without problems. But, I mostly code C++ and C#, both are strongly typed, so the compiler helps a lot with refactors.
- jblow 9y ago
  Exactly. Most proponents of unit tests use horrible programming languages; they are afraid to change code because anything could break at any time. Stop using those languages and most of the problems 'fixed' by unit testing just disappear.
  - juandazapata 9y ago
    Kent Beck, Alan Kay, Martin Fowler and Uncle Bob Martin must be all wrong then.

As long as there are suitable integration and system tests, this is no problem at all. Bonus if there are defensive assertions as recommended in the paper (design-by-contracts style). Sometimes it is easier to refactor a system without lots of unit-tests, as you need to update/fix lots of tightly coupled tests. What matters is what the system does (as seen from the outside), not how the underlying classes/functions work. They are mostly incidental.

wtetzner 9y ago

Refactoring code usually means you have to refractor unit tests as well, since they are so closely tied to the structure of the code. Integration tests, however, should not have to change, since they are typically run against the external interface to the software, which shouldn't change if you're just doing a refactoring.

juandazapata 9y ago
Funny thing. Unit tests force you to think about good code design. Integration tests don't. If you only have integration tests in your system, you'll most likely end up with a big ball of mud. I've seen this so many times in so many real world projects that it hurts.
- mannykannot 9y ago
  > Funny thing. Unit tests force you to think about good code design. Integration tests don't. They absolutely do, but at higher levels of abstraction, in terms of interfaces, interactions, constraints, obligations and responsibilities. In fact, unit and integration tests make you think about design in essentially the same way.
  - juandazapata 9y ago
    Whatever floats your boat. My experience in large enterprise products is exactly the opposite, but I'm glad it works for you.
- wtetzner 9y ago
  Except that in my experience, unit tests just end up being a big ball of mud too. And at that point, they don't make refactoring easier, they actually make it harder. Having good integration tests means that you're free to completely re-organize your code, and you can still test that it works as expected. Given that requirements change over time, even a well thought out code structure will likely need to be refactored at some point, and being able to have a test suite that doesn't have to be re-written during a refactoring is extremely valuable. I've also seen code bases become unnecessarily complex because so much thought was put into how to unit test it, that not enough thought was put into writing clear, easy to understand code.
wmil 9y ago
Yes, but broken tests at least give you hints about where you need to fix things. It can be hard to find every piece of code that relies on something you're changing.

Const-me 9y ago

Did that many times without problems. But, I mostly code C++ and C#, both are strongly typed, so the compiler helps a lot with refactors.

jblow 9y ago
Exactly. Most proponents of unit tests use horrible programming languages; they are afraid to change code because anything could break at any time. Stop using those languages and most of the problems 'fixed' by unit testing just disappear.
- juandazapata 9y ago
  Kent Beck, Alan Kay, Martin Fowler and Uncle Bob Martin must be all wrong then.