The way it is explained in incremental, step-by-step order makes this video feels smooth, easy to follow, and beginner friendly. Even though it's already 8 years old, it's one of the best refactoring video around. Thanks a lot sir!
Finally a testing video showing ACTUAL testing in real life. Instead of in a pristine, best-case-scenario where there are zero dependencies and oooh ‘magically the only thing that needs to be tested are pure functions’.
This is a really fantastic video. I am C# developer and I was still able to follow along perfectly and learn SO much. Thanks so much for sharing this, you should be proud!
I also agree. I got a SDE job and my first project is refactoring a massive program with hundreds of classes partially in C# and VB. I had no idea where to start and there are code smells all over. This video has helped me tremendously by applying the same concepts
Here is the Github repository: github.com/sandromancuso/trip-service-kata Feel free to clone and play with it. :) When you do, push your solution to your own Github and send us the link adding a comment here. I would love to see different solutions and approaches to it. Thanks for watching the video.
Absolutely. Both PowerMock and JMockit are an alternative. I, personally, discourage the use of both since they allow us to test things we should not be testing, like private methods and other internals. Since they make testing legacy code easier, developers are less inclined to see the issues the code really has. Some people use the expression "listening to our tests". Basically, what it means is if it is too difficult to test, almost always is because the code is not good enough.
Very good video on writing clean code with refactoring. I liked the various shortcuts you used as well. Almost a putting it all together kind. Thanks for sharing!
Thank you very much for this in-depth refactoring work! Very specific and practical examples with general and powerful techniques. I certainly learned a lot seeing you in action!
@@PlerbyMcFlerb It's called "Extract And Override" and is one of the techniques to create a seam taught by Michael Feathers in his book "Working Effectively with Legacy Code". If you were starting from scratch you'd likely be using dependency injection but since that's breaking the public interface and having to update lots of classes just to make it compile again, it's way better to use E&O.
Except now you are not testing how your class is interacting with its collaborators at all. You could replace getLoggedInUser() implementation with throw Unimplemented() and your tests will still be all green.
This was an exceptionally insightful and helpful video. I've been trying to teach myself good TDD recently, and one of my big hurdles has been dealing with legacy code (the other being figuring out how to begin testing MVC frameworks). Subscribed and I will be ordering your book. Thank you again for your excellent tutorial!
Thank you for publishing this video. This is an asset to the world, because it teaches developers to write good quality code. Publish other videos addressing different challenges, its a great social service
I really enjoyed this video. Your experience shines through in even the smallest change you perform - even choosing the most expressive method names is an art that takes a long time to perfect. This is going to help me a lot at my current task at work! My favourite bit was your test naming convention.
The last step, where I include Spring, was just a demonstration of what you can do in case you are already using Spring. I found it useful to add to the exercise since the vast majority of the Java projects use it. I just wanted to show how you can make Mockito work with the Spring @Autowired annotation. You can ignore the last step if you don't use Spring. An alternative would be to pass the TripDAO to the TripService constructor, in case you want to do dependency injection by hand.
I cannot add links to the comments. The TH-cam link above does not work. Search on TH-cam for Johan Martinsson "A few general tricks for simplifying conditional logic"
It is awesome this way! Thank you so much. The tips you have given are great to start refactoring the legacy code and write UT. => Start testing from shortest branch to deepest branch. => Start refactoring from deepest branch to shortest branch Q1: should we more focus on loosely couple architecture and avoid static methods so that we can mock the dependencies?
Reallt good video. Immediately adopted your naming scheme for tests, great solution to what I was missing most coming to Java from RSpec (the descriptions). Hope to see more videos in the future. Thanks alot.
Thanks Christoffer. Anyone coming from RSpec will definitely find the Java testing frameworks a little bit clunky. But with a few tweaks here and there we can make it look OK. A common alternative is to write the tests using Spock. I'm glad you liked the video.
Truly a great video. Some very simple but powerful techniques that have helped me refactor any code base not just a Java application. Thank you Sandro for a great tutorial!
finally a practical refactoring example, thank you very much. but I have a question. I think there was a better work around for isolating TripDAO static class. you could define an non static adapter class for it then wrap it, afterwards you could extract an interface from the wrapper class and inject it through TripService constructor.
Thank you. Glad you liked it. The approach you suggested would certainly work, mainly if you really don't want or cannot change the TripDAO. I found it simpler just to add an instance method that uses the static. This way I can inject and mock the DAO, using the instance method instead. And if one day, all the references to the DAO are using the instance method, I could kill the static. Just a matter of preference. But both solutions would work fine.
Amazing video, as a not so experienced developer, I've been watching several talks of the theory behind all these, but finally watching it in action is very very helpful. Hope you continue making these screen casts. Could you recommend me some books/sites about: 1) General IDE/Frameworks tips/tricks to improve productivity 2) Java design patterns and taking advantage of the features of the language (as you did with your builder, and the addFriends(User... users) example) 3) Re-factoring/Testing
Questo video è davvero fantastico, complimenti! Riesci a spiegare in un modo chiaro è semplice come si può, in effetti, rendere "testabile" un'applicazione "legacy". Lo faccio vedere a tutti i miei colleghi.
An alternative is to use a mocking tool when writing the tests. PowerMock and JMockit are two such tools which allow the creation of unit tests without first changing the code to be tested, even if it calls static methods.
Sir will you please upload more videos explaining the refactoring and testing of legacy code... It will be very hepful for us.... Thanks for uploading this video. Its a request to plz upload more videos and practical explanation on refactoring...
this video is great ! however the last part of TripDao static to instance will break the function even it pass the test. It need to be initialize somewhere
Excellent refactoring, but refactoring it's still incomplete because by including Spring you are going beyond unit testing. In a real project, without Spring you would need to configure the project to use Spring, and so to do acceptance tests to verify that injection is working.
Sadly you broke your "production code" in this video :( When moving the use of a global variable into your members argument list you cannot replace its default value with null all over the code base like that. It must be replaced with the value it had before you made it an argument, which in this case would be the global variable call. Yes it would stick in peoples eyes but it would be very visible everywhere that this global is now used as an argument, which would make it easy to fix when those other parts of code is to be updated. Anyways, keep up the good work :)
What should I do if I have been refactoring for thirty minutes, getting green every time and suddenly realize that I have been running the wrong test suite the entire time?
34:03 I still don't get it why tripBy is the deepest code in the function instead of that for loop? Did i missed something in the video? Can anyone help me😅 Or maybe branch means if/switch case?
Could someone please explain why by the time: 23:27 the lines 35 and 37 are marked *RED* in the *TripServiceTest.java* Thanks in advance for taking the time and thinking about it Awesome video by the way. Top knowledge in short time 👍👍👍
I would probably have preferred passing some sort of interface that exposes a method for getting the logged in user, rather than passing a user and just hoping that people read the name of the parameter. might not be completely necessary, but to me it communicates intent more if you ask for a provider os the logged in user, rather than asking for a user and saying "ps please make sure it's the logged in one". it makes it harder to write wrong code.
The way it is explained in incremental, step-by-step order makes this video feels smooth, easy to follow, and beginner friendly. Even though it's already 8 years old, it's one of the best refactoring video around. Thanks a lot sir!
I wish someone showed me this 9 years ago, I would have kept so many legacy code revamp jobs that I attempted and failed
Finally a testing video showing ACTUAL testing in real life. Instead of in a pristine, best-case-scenario where there are zero dependencies and oooh ‘magically the only thing that needs to be tested are pure functions’.
Yes
This kind of thing is still not taught in any school
What one learns from this video is what beginners learn after years of experience. Thank you very much for this video... Truely grateful.
Thank you.
Definitely one of the best videos about testing and refactoring, thank you !
0:50 Legacy code rule
1:18 Tips:
- Start testing from shortest branch to deepest branch.
- Start refactoring from deepest branch to shortest branch.
6:02: Tip for testing with outside (cannot mock) dependence.
57:20 Refactoring static method.
Definitely one of the best videos about testing and refactoring.
This is a really fantastic video. I am C# developer and I was still able to follow along perfectly and learn SO much. Thanks so much for sharing this, you should be proud!
+Samantha Webb agreed, this helped me so much in getting a feel for how to deal with legacy code and how to design my tests in general!
I also agree. I got a SDE job and my first project is refactoring a massive program with hundreds of classes partially in C# and VB. I had no idea where to start and there are code smells all over. This video has helped me tremendously by applying the same concepts
Here is the Github repository: github.com/sandromancuso/trip-service-kata
Feel free to clone and play with it. :)
When you do, push your solution to your own Github and send us the link adding a comment here. I would love to see different solutions and approaches to it.
Thanks for watching the video.
Absolutely. Both PowerMock and JMockit are an alternative. I, personally, discourage the use of both since they allow us to test things we should not be testing, like private methods and other internals. Since they make testing legacy code easier, developers are less inclined to see the issues the code really has. Some people use the expression "listening to our tests". Basically, what it means is if it is too difficult to test, almost always is because the code is not good enough.
There's not many refactoring tutorials as good as this! Thx.
Thank you
Very good video on writing clean code with refactoring. I liked the various shortcuts you used as well. Almost a putting it all together kind. Thanks for sharing!
Thank you very much for this in-depth refactoring work! Very specific and practical examples with general and powerful techniques. I certainly learned a lot seeing you in action!
6:55 the seam technique is so good. actually solves 90% of the legacy code testability issues :D
Thanks for calling attention to that one! It is really useful.
Feels a bit like test induced damage to introduce inheritance like that, but you can always refactor it later, I guess
@@PlerbyMcFlerb It's called "Extract And Override" and is one of the techniques to create a seam taught by Michael Feathers in his book "Working Effectively with Legacy Code". If you were starting from scratch you'd likely be using dependency injection but since that's breaking the public interface and having to update lots of classes just to make it compile again, it's way better to use E&O.
Except now you are not testing how your class is interacting with its collaborators at all. You could replace getLoggedInUser() implementation with throw Unimplemented() and your tests will still be all green.
Finally took the time to do this kata. It's great to see your pov afterwards. Thanks for sharing!
This was an exceptionally insightful and helpful video. I've been trying to teach myself good TDD recently, and one of my big hurdles has been dealing with legacy code (the other being figuring out how to begin testing MVC frameworks). Subscribed and I will be ordering your book. Thank you again for your excellent tutorial!
Thank you for publishing this video. This is an asset to the world, because it teaches developers to write good quality code. Publish other videos addressing different challenges, its a great social service
Such a great tutorial. Explained all the basics about the unit testing. Expecting these kind of videos again.
Thanks, Abhilash. You might want to look at our Codurance channel. All new videos are there. th-cam.com/users/codurance
Very good insights on how to deal with coupled legacy code, thanks man! 👏👏
I really enjoyed this video. Your experience shines through in even the smallest change you perform - even choosing the most expressive method names is an art that takes a long time to perfect. This is going to help me a lot at my current task at work! My favourite bit was your test naming convention.
Feel like ive been searching for this since forever
It was pleasure to see. Very informative and practical. Thank you!
The last step, where I include Spring, was just a demonstration of what you can do in case you are already using Spring. I found it useful to add to the exercise since the vast majority of the Java projects use it.
I just wanted to show how you can make Mockito work with the Spring @Autowired annotation. You can ignore the last step if you don't use Spring. An alternative would be to pass the TripDAO to the TripService constructor, in case you want to do dependency injection by hand.
I cannot add links to the comments. The TH-cam link above does not work. Search on TH-cam for Johan Martinsson "A few general tricks for simplifying conditional logic"
I have not seen any other video which is as good as this one. Great. Cast more of these pls.
It is awesome this way! Thank you so much.
The tips you have given are great to start refactoring the legacy code and write UT.
=> Start testing from shortest branch to deepest branch.
=> Start refactoring from deepest branch to shortest branch
Q1: should we more focus on loosely couple architecture and avoid static methods so that we can mock the dependencies?
Here are a few more videos, some by my colleagues, some by me. : codurance.com/publications/videos/
My compliments! A very useful tutorial, and it's a joy to watch you code.
Thank you. I deal with the legacy code quite often and I think I will find this lesson useful.
Reallt good video. Immediately adopted your naming scheme for tests, great solution to what I was missing most coming to Java from RSpec (the descriptions).
Hope to see more videos in the future. Thanks alot.
Thank you so much for the video. I think you just got me a new job
Thanks Christoffer. Anyone coming from RSpec will definitely find the Java testing frameworks a little bit clunky. But with a few tweaks here and there we can make it look OK. A common alternative is to write the tests using Spock. I'm glad you liked the video.
Truly a great video. Some very simple but powerful techniques that have helped me refactor any code base not just a Java application. Thank you Sandro for a great tutorial!
finally a practical refactoring example, thank you very much. but I have a question. I think there was a better work around for isolating TripDAO static class. you could define an non static adapter class for it then wrap it, afterwards you could extract an interface from the wrapper class and inject it through TripService constructor.
Thank you. Glad you liked it. The approach you suggested would certainly work, mainly if you really don't want or cannot change the TripDAO. I found it simpler just to add an instance method that uses the static. This way I can inject and mock the DAO, using the instance method instead. And if one day, all the references to the DAO are using the instance method, I could kill the static. Just a matter of preference. But both solutions would work fine.
I just added the link on the description of the video. TH-cam doesn't allow me to add links when posting a comment.
You win my like, it's an excellent video. I look forward to seeing the next videos.
Thank you
Very good video, thank you kind Sir.
Amazing video, as a not so experienced developer, I've been watching several talks of the theory behind all these, but finally watching it in action is very very helpful.
Hope you continue making these screen casts.
Could you recommend me some books/sites about:
1) General IDE/Frameworks tips/tricks to improve productivity
2) Java design patterns and taking advantage of the features of the language (as you did with your builder, and the addFriends(User... users) example)
3) Re-factoring/Testing
Paused to check if the noise is from your CPU fan or mine :) Great video.
Questo video è davvero fantastico, complimenti! Riesci a spiegare in un modo chiaro è semplice come si può, in effetti, rendere "testabile" un'applicazione "legacy". Lo faccio vedere a tutti i miei colleghi.
An alternative is to use a mocking tool when writing the tests. PowerMock and JMockit are two such tools which allow the creation of unit tests without first changing the code to be tested, even if it calls static methods.
Thank you so much! Great and very inform video. I'm new to Unit-Testing (C#) and this video is very helpful.
It would be nice if Sandro allowed others to modify his git code so people with further ideas like you could continue the refactoring.
It was awesome that way! Thank u so much for the wonderful session! *Appreciation*
Such a great lesson!!! thanks Sandro!!!!
Bravo! Thank you for taking the time to make this excellent video!
What a beautyful piece of code! It was like whatching a paiting, enjoyable
Wow, great video even in 2018! Helped me understand some things I had been wondering about.
great movie, you should do more !
I really enjoyed it.
excellent demo with real time code refactoring!
really good thanks a lot , how are you running "code coverage" command in elipse?
This was fantastic! I really did learn a lot.
Just excellent ! a good job
This was eye-opening for me, thanks
Excellent.
Shorter to deepest path.
Any recommendations as to hierarchy order ? Bottom up ?
best cast i seen about this topic
Incredibly well done. Thanks so much for the effort.
Feel free to do more!
Thanks Johannes
You are absolutely right. I totally forgot to refactor the ArrayList and use the Collections.emptyList() instead.
Great video on refactoring legacy code.
Second time to review. It is an awesome tutorial.
very well thought of and presented..
Masterpiece. Sharing this with all my team. Thank you Sandro!
Sandro, it was very very nice! I'll be brave now. =) And your kata is a nice subject for a dojo. Abraão Alves Nelson Eldoro
Thanks Danilo.
Thank you, this video basically answered all my question.
Yes this well though but why are we introducing auto wiring in production code ?
This will change the start up behaviour ?
very nice test driven development
As many likes as subscribers, but you deserve more
Very good video! it was very inspiring and i enjoyed it a lot. thanks!
Thanks for the presentation!
Sir will you please upload more videos explaining the refactoring and testing of legacy code...
It will be very hepful for us....
Thanks for uploading this video.
Its a request to plz upload more videos and practical explanation on refactoring...
Thank you for watching. There are a few more videos here: codurance.com/publications/videos/
Good session. Very useful. Thanks a lot.
Initially, I thought "One hour and seventeen min?! No way!". One hour and seventeen minutes later... "Already over? Do not stop!" :)
Wooow lovely thanks a lot Sandro for this video
I'll definitely give your video as food for thought and action to my team =)
Thank you very much for this awesome demonstration!!!
Great video, thanks for sharing. Can you post some additional refactoring resources you recommend?
Awesome tutorial. Thank you!
this video is great ! however the last part of TripDao static to instance will break the function even it pass the test. It need to be initialize somewhere
Thanks for this great video! learned a lot!
Great video ... thank you for sharing
Thank you. Piece of really good job.
Awesome video, do you plan on making any more videos like this one?
Very very good video! Thank you!
Excellent refactoring, but refactoring it's still incomplete because by including Spring you are going beyond unit testing. In a real project, without Spring you would need to configure the project to use Spring, and so to do acceptance tests to verify that injection is working.
Sadly you broke your "production code" in this video :( When moving the use of a global variable into your members argument list you cannot replace its default value with null all over the code base like that. It must be replaced with the value it had before you made it an argument, which in this case would be the global variable call. Yes it would stick in peoples eyes but it would be very visible everywhere that this global is now used as an argument, which would make it easy to fix when those other parts of code is to be updated.
Anyways, keep up the good work :)
Enjoyed watching this!
Is the @Spy useful?
I don't think so and I heard it's a bad habit to use @Spy.
Thank you.! I have learned from this video too much.
What should I do if I have been refactoring for thirty minutes, getting green every time and suddenly realize that I have been running the wrong test suite the entire time?
how are you copying/moving data from one block to another @15:00??
Thanks a lot for sharing this. Cheers
34:03
I still don't get it why tripBy is the deepest code in the function instead of that for loop?
Did i missed something in the video?
Can anyone help me😅
Or maybe branch means if/switch case?
Are we forcing Spring to inject the Dao during start and How are we sure that this will not break anywhere else ?
That DAO literally has a static method. So he knows it won't break anything
Thank you alot for this interesting tuto.. :-)
Could someone please explain why by the time: 23:27 the lines 35 and 37 are marked *RED* in the *TripServiceTest.java*
Thanks in advance for taking the time and thinking about it
Awesome video by the way. Top knowledge in short time 👍👍👍
I would probably have preferred passing some sort of interface that exposes a method for getting the logged in user, rather than passing a user and just hoping that people read the name of the parameter.
might not be completely necessary, but to me it communicates intent more if you ask for a provider os the logged in user, rather than asking for a user and saying "ps please make sure it's the logged in one". it makes it harder to write wrong code.
My pleasure. Thanks.
Really good video.
Thank you for this video. Just thank you...
13:09 audio clears up
Great video..
Thanks a lot Sir
Great video! Thanks a lot :)