WEBVTT 00:00:00.020 --> 00:00:04.440 Hello and welcome to Python Bytes, where we deliver Python news and headlines directly to earbuds. 00:00:05.060 --> 00:00:09.560 This is episode 461, recorded December 9th, 2025. 00:00:10.180 --> 00:00:11.120 And I am Brian Okken. 00:00:11.300 --> 00:00:12.300 And I am Michael Kennedy. 00:00:12.700 --> 00:00:17.100 And this episode is sponsored by yours truly and Michael. 00:00:17.280 --> 00:00:19.680 So both of us Talk Python Training. 00:00:20.180 --> 00:00:22.060 Always some great stuff. 00:00:22.080 --> 00:00:29.080 I just finished the AI, the recent AI agent course. 00:00:29.340 --> 00:00:29.720 Oh, you did? 00:00:29.820 --> 00:00:36.120 great yeah thank you yeah awesome really enjoyed it uh some great content there and um so but 00:00:36.240 --> 00:00:40.260 there's plenty of other stuff to do there's even a py test course there but if you'd like a really 00:00:40.560 --> 00:00:46.080 complete py test course head on over to python test.com we have uh there's the complete course 00:00:46.320 --> 00:00:52.680 there uh thanks to patreon supporters also there's um a new book out from michael and uh and a book 00:00:52.780 --> 00:00:58.079 that i'm working on so lots of ways you can support us and if you don't if you just want to support us 00:00:58.100 --> 00:00:59.040 by sending us topics. 00:00:59.400 --> 00:01:00.120 We'd like that too. 00:01:00.660 --> 00:01:01.680 You can connect with us. 00:01:02.020 --> 00:01:03.860 There's a contact form on the website 00:01:04.120 --> 00:01:05.280 on pythonbytes.fm 00:01:05.400 --> 00:01:08.200 or you can reach us on Bluesky or Mastodon. 00:01:08.560 --> 00:01:10.180 And if you'd like to, if you're listening, 00:01:10.620 --> 00:01:11.480 we love you. 00:01:11.860 --> 00:01:14.360 But we also would like you to check out 00:01:14.540 --> 00:01:16.280 our video stuff every once in a while. 00:01:16.640 --> 00:01:18.820 Head on over to pythonbytes.fm/live 00:01:18.820 --> 00:01:20.180 and you can be part of the audience 00:01:20.300 --> 00:01:21.480 or just watch it afterwards. 00:01:22.360 --> 00:01:25.319 And finally, please subscribe to our newsletter 00:01:25.340 --> 00:01:29.620 or essentially it's occasionally we send out little news bits, 00:01:29.840 --> 00:01:32.920 but mostly it's the show notes from the show. 00:01:32.980 --> 00:01:36.020 So we send out, after we get it all done, 00:01:36.140 --> 00:01:38.080 we send out a newsletter that has all the links 00:01:38.240 --> 00:01:40.180 so you don't have to take notes while you're listening. 00:01:40.520 --> 00:01:42.240 Now for our first topic, Michael. 00:01:42.480 --> 00:01:45.660 Our first topic is going to be a tour of peps, 00:01:45.880 --> 00:01:49.340 a brand new PEP in a PEP that we spent a fair amount of time talking about. 00:01:49.660 --> 00:01:54.460 The first one is PEP 798, Unpacking in Comprehensions. 00:01:55.280 --> 00:01:58.340 So this one is a little bit funky. 00:01:58.400 --> 00:02:01.980 It's currently in draft stage targeting Python 3.15. 00:02:02.480 --> 00:02:07.900 It's pretty minor, but I think it brings some consistency to it. 00:02:07.900 --> 00:02:09.759 So I linked to the conversation here. 00:02:09.759 --> 00:02:14.040 And the idea is right now, if I have a function that 00:02:14.220 --> 00:02:17.300 takes an arbitrary number of positional keywords, 00:02:17.880 --> 00:02:20.360 you would say star args, right? 00:02:20.500 --> 00:02:25.240 Star args, star kwa args is like a pretty common theme 00:02:25.260 --> 00:02:37.180 So if I had something that said star args, and I wanted to push a tuple of values as those positional parameters, I would say star tuple in the function call. 00:02:37.500 --> 00:02:41.060 Kind of like you say star star for a dictionary to say keyword arguments, right? 00:02:41.230 --> 00:02:52.200 So the idea here is that that works for function calls, but it doesn't work for comprehensions, list comprehensions, set comprehensions, and so on, if you have an iterable. 00:02:52.500 --> 00:02:56.480 Right now what we have, and this is super confusing to me, I always get the order wrong, 00:02:56.570 --> 00:03:04.020 or at least I'm always uncertain of the order, is I can say, you know, basically X for X in Y, 00:03:04.920 --> 00:03:11.300 Y for Y in thing, if I've got a set of lists or intervals and I want to turn them into 00:03:11.830 --> 00:03:15.440 like one big list as a comprehension, you can basically do like a double comprehension 00:03:15.980 --> 00:03:21.420 in one thing. And I'm always like, which one is the collection and which one is the item, 00:03:21.640 --> 00:03:24.740 you know, so this kind of solves that. 00:03:24.960 --> 00:03:27.680 It says you can just say in the comprehension, 00:03:27.780 --> 00:03:32.260 you say star iterable for iterable in some list of iterables. 00:03:32.620 --> 00:03:33.920 And it makes it real simple, right? 00:03:34.040 --> 00:03:37.860 So you can do that for, pulled up official pep. 00:03:37.980 --> 00:03:41.800 You can do it for list comprehensions, set comprehensions, 00:03:42.340 --> 00:03:43.460 dictionary comprehensions. 00:03:43.540 --> 00:03:47.260 If you have a list, if you have an iterable of dictionaries, 00:03:47.340 --> 00:03:48.840 you can create a dictionary comprehension. 00:03:49.340 --> 00:03:50.720 And you can do it for generators. 00:03:50.800 --> 00:03:53.720 if your generator generates iterables. 00:03:54.220 --> 00:03:54.560 Does that make sense? 00:03:55.180 --> 00:03:55.320 Yeah. 00:03:55.800 --> 00:03:58.040 So that's pretty much it. 00:03:58.040 --> 00:03:58.440 What do you think? 00:03:59.360 --> 00:03:59.700 That's cool. 00:03:59.760 --> 00:04:01.340 So that's not something you do now? 00:04:01.540 --> 00:04:02.360 This is a proposal? 00:04:02.640 --> 00:04:03.300 Is that right? 00:04:03.300 --> 00:04:05.660 Yes, this is a draft for 3.15. 00:04:06.080 --> 00:04:06.300 Okay. 00:04:06.800 --> 00:04:08.460 And just shout out for a little bit of credit. 00:04:08.760 --> 00:04:11.200 This is Adam Hartz and Eric Demain 00:04:12.040 --> 00:04:13.680 for the people proposing it. 00:04:13.760 --> 00:04:16.900 And the sponsor is Yelda Zilastra. 00:04:17.180 --> 00:04:18.579 Sorry, if I messed that up, 00:04:18.640 --> 00:04:19.840 I gave it my best shot, folks. 00:04:20.420 --> 00:04:23.060 So anyway, that's my main topic here for this first one 00:04:23.260 --> 00:04:26.140 is this unpacking in comprehensions. 00:04:26.360 --> 00:04:28.920 We've had unpacking in other places, into variables. 00:04:29.180 --> 00:04:30.820 We've had unpacking into function calls. 00:04:30.960 --> 00:04:32.260 We have not had them in comprehensions. 00:04:32.370 --> 00:04:34.480 And they've honestly, this double comprehension, 00:04:34.960 --> 00:04:36.240 like double layered comprehension thing 00:04:36.270 --> 00:04:37.960 has always been complicated. 00:04:38.460 --> 00:04:39.440 And so I'm here for it. 00:04:39.620 --> 00:04:41.620 I mean, it does add another thing to language 00:04:41.800 --> 00:04:43.480 and everything you add to a language 00:04:43.820 --> 00:04:44.980 just makes it more complicated. 00:04:45.820 --> 00:04:48.720 But in this case, I think it's well worth it. 00:04:49.040 --> 00:04:50.260 Now, go ahead. 00:04:50.460 --> 00:04:59.940 Oh, I just wanted to say, speaking of the unpacking, use the star or asterisk, but one of my favorite names for that character is splat. 00:05:00.500 --> 00:05:00.860 Splat. 00:05:01.180 --> 00:05:01.440 Splat. 00:05:01.660 --> 00:05:03.600 Let's call them splatted comprehensions. 00:05:04.060 --> 00:05:04.380 Here, hold on. 00:05:04.830 --> 00:05:06.700 I'll just edit this and we'll fix this real quick. 00:05:07.700 --> 00:05:12.360 I'm going to change the, you know what, my screen is too small. 00:05:12.580 --> 00:05:13.680 I was going to edit the text, right? 00:05:13.780 --> 00:05:15.080 Okay, so that's all good. 00:05:15.160 --> 00:05:19.440 Now the next one is just a really quick follow-up on a PEP as well. 00:05:19.840 --> 00:05:21.680 Before we move off of Focus on Me. 00:05:22.040 --> 00:05:26.280 Remember how excited you were and I was about explicit lazy imports? 00:05:26.380 --> 00:05:28.260 As in lazy... 00:05:29.199 --> 00:05:30.540 Are they going to take it out? 00:05:30.840 --> 00:05:30.960 No. 00:05:31.680 --> 00:05:34.680 Dear Pep 810 authors, Barry Warsaw writes, 00:05:35.200 --> 00:05:41.900 this steering council is happy, happy to unanimously accept Pep 810 explicit lazy imports. 00:05:42.040 --> 00:05:42.680 Congratulations. 00:05:43.320 --> 00:05:44.520 You now have a job to implement. 00:05:44.620 --> 00:05:45.960 And it's, yeah. 00:05:46.400 --> 00:05:48.600 The same is true for all the other alternative keywords 00:05:48.800 --> 00:05:49.620 we come up with. 00:05:49.820 --> 00:05:51.060 So lazy it is. 00:05:51.600 --> 00:05:51.860 I know. 00:05:52.120 --> 00:05:53.220 That's anyway, a little bit of background 00:05:53.380 --> 00:05:55.700 on some of the thinking the steering council put out there. 00:05:55.900 --> 00:05:57.780 But yeah, unanimously and happy. 00:05:58.180 --> 00:05:58.480 Yay. 00:05:59.000 --> 00:05:59.060 Good. 00:05:59.340 --> 00:06:00.700 Yeah, that's pretty good. 00:06:00.900 --> 00:06:02.120 So happy to see that. 00:06:02.200 --> 00:06:03.960 And by the way, just a little shout out 00:06:04.260 --> 00:06:05.120 for the live stream folks. 00:06:05.520 --> 00:06:07.880 I'm going to have Barry Warsaw and a bunch of other folks 00:06:08.420 --> 00:06:10.980 on to do a year in review three hours, 00:06:11.680 --> 00:06:13.880 two hours and 40 minutes from now on Talk Python. 00:06:14.520 --> 00:06:16.680 So that's going to be fun. 00:06:16.780 --> 00:06:19.460 We'll hear from Barry over there, but probably not about the path. 00:06:19.680 --> 00:06:20.260 All right, over to you, Brian. 00:06:21.240 --> 00:06:22.160 What am I talking about? 00:06:22.360 --> 00:06:29.160 I'm going to talk about another new release or an upcoming release, Pandas 3.0. 00:06:29.520 --> 00:06:33.480 So the Pandas 3.0.0, so 3.0.0. 00:06:33.780 --> 00:06:38.140 There's a release candidate zero that's been out since sometime last week. 00:06:40.060 --> 00:06:44.100 And then apparently there's going to be an official 3.0 released in a few weeks. 00:06:44.640 --> 00:06:48.520 but that was a week ago so maybe a couple weeks from now not sure um so what do we got in here 00:06:48.680 --> 00:06:54.140 i'm pretty excited about this actually uh we've got um what's new there's a there's a dedicated 00:06:54.440 --> 00:07:00.980 string data type by default and this is just kind of great so if uh normally in things that with 00:07:01.200 --> 00:07:05.820 strings in them they would show up as objects but clearly they're strings so there's a new string 00:07:06.020 --> 00:07:12.879 type um and it does change things a bit um if you have any the any missing things it'll be an uh 00:07:13.080 --> 00:07:16.400 N-A-N, sentinel, to say that there's nothing there. 00:07:17.240 --> 00:07:21.540 What's great about this is once you have this str type, D type, 00:07:22.300 --> 00:07:26.160 or str D type, you can only put strings or nans in it. 00:07:26.280 --> 00:07:27.980 There's nothing else allowed. 00:07:29.260 --> 00:07:30.880 So nothing weird shows up. 00:07:31.140 --> 00:07:32.460 It's not just a generic object. 00:07:33.160 --> 00:07:35.200 There's a lot of other implications around this. 00:07:36.170 --> 00:07:40.120 The str can only hold strings in the sentinel, of course. 00:07:40.220 --> 00:07:43.780 The missing values are sentinel inferred by default for string data. 00:07:45.580 --> 00:07:50.960 Anyway, check out the PEP 14 to get a little more information. 00:07:51.340 --> 00:07:54.520 There will, there's other implications around this, but I think it's a really good thing. 00:07:54.880 --> 00:07:59.020 Copy on write also is kind of a really exciting thing that hopefully nobody will really notice. 00:07:59.420 --> 00:08:08.200 But the idea is really anything that results in an indexing operation will return essentially a copy of things. 00:08:08.520 --> 00:08:10.600 So you don't, there's not, or not, not a copy. 00:08:10.720 --> 00:08:11.300 It'll be a reference. 00:08:12.100 --> 00:08:16.420 It's, and it only, only makes a copy of actually modify something. 00:08:16.780 --> 00:08:20.980 So, so pandas will keep track of whether or not you've changed it. 00:08:20.980 --> 00:08:23.300 And if you haven't changed it, it's just a copy of the data there. 00:08:23.420 --> 00:08:26.220 This will say, this should save a lot of time and space. 00:08:26.610 --> 00:08:29.760 So I think that's going to save a ton of, especially memory. 00:08:30.260 --> 00:08:35.060 Because if I remember correctly, I'm not a pandas expert by any stretch of the imagination. 00:08:35.180 --> 00:08:42.340 But when you call operations like filter operations or other transform operations, it doesn't in place modify it. 00:08:42.460 --> 00:08:43.580 It returns a new data frame. 00:08:43.860 --> 00:08:50.440 Like if I add a column to a data frame with the operation, I get an entire copy of that data frame plus the column. 00:08:50.700 --> 00:08:51.660 You know, one of the new column. 00:08:52.020 --> 00:08:57.420 If you've got five million rows loaded and you call those five or ten times, like you're all of a sudden, it's piling up fast. 00:08:57.740 --> 00:08:57.920 Yeah. 00:08:58.140 --> 00:09:02.440 And it says the main goal is to change the user API to be more consistent and predictable. 00:09:02.660 --> 00:09:06.280 And I think this is right because, I mean, we're doing like matrix operations and stuff, 00:09:06.620 --> 00:09:11.220 and we'd really like it to be kind of like math where you don't really care about the 00:09:12.500 --> 00:09:14.280 size or timing implications. 00:09:14.600 --> 00:09:15.900 You're just, this is what I want to do. 00:09:16.460 --> 00:09:20.200 And having that be more consistent and hidden behind the scenes, I think it's going to be 00:09:20.340 --> 00:09:20.460 great. 00:09:20.720 --> 00:09:22.660 It's going to make this a lot easier to learn. 00:09:23.300 --> 00:09:25.160 They're cleaning up a lot of the API and stuff. 00:09:25.600 --> 00:09:26.440 It's really cool. 00:09:27.120 --> 00:09:30.180 We had covered this in one of the other episodes that was coming. 00:09:30.620 --> 00:09:37.000 PD call syntax can now be used in data frame assign and location. 00:09:37.500 --> 00:09:40.320 And this idea is that basically you could just say, 00:09:40.570 --> 00:09:44.600 I want to assign a new column with the addition of like two other columns or something, 00:09:44.690 --> 00:09:45.520 or some operation. 00:09:45.940 --> 00:09:48.300 And it just does it right there. 00:09:48.640 --> 00:09:51.480 Like instead of having to do a lambda expression inside, 00:09:51.550 --> 00:09:52.760 you can just do the expression. 00:09:52.890 --> 00:09:54.580 It's really kind of a great syntax. 00:09:55.020 --> 00:09:58.500 We've got a copy of the syntax in the show notes, but that's pretty great. 00:09:58.700 --> 00:10:06.780 Some changes to deprecation policy, probably because of some of these changes that they're doing a three-stage deprecation thing. 00:10:07.730 --> 00:10:08.800 But I think this is good. 00:10:08.810 --> 00:10:12.560 I think that basically open source projects are being used more. 00:10:12.810 --> 00:10:20.360 The ones that they have to think about this, how to keep track, keep it fun to maintain, but also moving with the times. 00:10:20.700 --> 00:10:21.700 And I think these are good calls. 00:10:22.360 --> 00:10:24.580 A bunch of other enhancements as well, so check those out. 00:10:24.860 --> 00:10:26.880 But I think this is a really good direction. 00:10:26.960 --> 00:10:29.240 and I can't wait to see 3.0 pandas come out. 00:10:29.540 --> 00:10:29.920 This will be great. 00:10:30.220 --> 00:10:31.220 Yeah, that's pretty exciting. 00:10:31.340 --> 00:10:32.220 That's a pretty major change. 00:10:33.640 --> 00:10:34.060 All right. 00:10:34.920 --> 00:10:35.460 What's up next? 00:10:35.840 --> 00:10:37.520 This episode has typos in it, Brian. 00:10:37.900 --> 00:10:38.320 Oh, no. 00:10:38.860 --> 00:10:39.480 I'll try to fix it. 00:10:39.780 --> 00:10:40.120 I know. 00:10:41.100 --> 00:10:43.140 Well, remember I spoke about code spell, 00:10:43.950 --> 00:10:44.980 all one word, code spell, 00:10:45.580 --> 00:10:47.920 and it was a misspelling finder, 00:10:48.400 --> 00:10:50.180 not a spell checker, right? 00:10:50.360 --> 00:10:51.640 The spell checker looks for words 00:10:51.820 --> 00:10:53.320 that it knows are good and says, 00:10:53.380 --> 00:10:54.120 I don't know that word. 00:10:54.190 --> 00:10:55.060 That must be misspelled. 00:10:55.420 --> 00:10:58.700 In programming, obviously, there's all these symbols and all sorts of stuff. 00:10:59.220 --> 00:11:05.440 One of the things that drives me crazy is when my editor suggests that a library that I'm importing is misspelled, 00:11:05.740 --> 00:11:07.860 but it's the library's name correctly. 00:11:08.000 --> 00:11:10.600 I'm like, hmm, well, I can't write it any other way. 00:11:10.720 --> 00:11:11.600 This is the only way it works. 00:11:11.780 --> 00:11:16.460 I'm sorry, spellchecker, but do I really got to go through and tell you that this is the name of the library I'm using? 00:11:16.840 --> 00:11:17.680 Yes, apparently I do. 00:11:18.320 --> 00:11:27.980 So this like code spell, this thing called typos, also looks for known misspellings like ADN for a common misspelling of and and so on. 00:11:28.240 --> 00:11:28.620 Super good. 00:11:28.980 --> 00:11:29.960 Why are we back? 00:11:30.220 --> 00:11:36.620 Well, Sky Cosco wrote and said, code spell is cool, but you should check out typos. 00:11:36.780 --> 00:11:39.620 So typos, I believe it is written in Rust. 00:11:39.780 --> 00:11:41.660 Yes, 99.9%. 00:11:41.780 --> 00:11:42.720 That's three nines Rust. 00:11:43.040 --> 00:11:43.400 Pretty good. 00:11:43.700 --> 00:11:45.740 And 0.0% Python, but it's still mentioned. 00:11:45.960 --> 00:11:49.980 So it must be less than one-tenth of 1%. 00:11:50.080 --> 00:11:52.520 But it's a little more full-featured for people that like this. 00:11:52.700 --> 00:11:57.360 So, for example, it has a GitHub action that you could just put into all of your PRs. 00:11:57.580 --> 00:11:58.600 That's kind of cool, if you want. 00:11:58.760 --> 00:12:01.780 It's like a gated thing for PRs and commits and so on. 00:12:02.020 --> 00:12:04.660 But the best thing about it, I guess two things. 00:12:05.100 --> 00:12:12.040 One is it uses the concrete syntax tree rather than actually just searching text. 00:12:12.540 --> 00:12:17.160 So what it can do is it can find partial bits of words that are misspelled. 00:12:17.520 --> 00:12:20.980 Maybe this is actually not related to that, but it does find partial misspellings. 00:12:21.420 --> 00:12:27.000 So for example, if you write connecton string instead of connection string with snake casing, 00:12:27.490 --> 00:12:28.800 whatever, it says, hey, guess what? 00:12:28.830 --> 00:12:33.320 The word connection and connection underscore string without the I is a misspell. 00:12:33.400 --> 00:12:38.360 Maybe you should change, you know, connecton to connection or connector or whatever. 00:12:38.860 --> 00:12:40.160 And it gives you a nice little UI for that. 00:12:40.430 --> 00:12:41.020 So that's one. 00:12:41.270 --> 00:12:41.920 I really like that. 00:12:41.960 --> 00:12:48.520 But like that's super cool that it can detect misspellings within, you know, snake case words. 00:12:48.830 --> 00:12:50.900 So, yeah, yeah, this is a it's a big improvement. 00:12:51.220 --> 00:12:53.680 And PyCharm does this as well, by the way, which is really nice. 00:12:53.710 --> 00:12:58.140 But I believe PyCharm is a built checker, not a misspelling finder or whatever. 00:12:58.880 --> 00:12:59.280 Pretty sure. 00:12:59.600 --> 00:13:01.680 Anyway, this is really nice that it does this. 00:13:01.960 --> 00:13:05.660 The other thing that's super cool, and this is why Sky wrote to us, 00:13:06.060 --> 00:13:12.100 is it actually has a VS Code in Friends extension in language server. 00:13:12.520 --> 00:13:16.600 So what you can do is basically install this as an extension in VS Code 00:13:16.820 --> 00:13:22.320 or Cursor or Google Antigravity or, you know, you name all the others, right? 00:13:22.820 --> 00:13:25.260 Because it's also in the OpenVSX registry. 00:13:25.620 --> 00:13:26.380 So you can install that there. 00:13:26.420 --> 00:13:29.639 And then just as you're writing code, you get little squigglies 00:13:29.740 --> 00:13:32.220 and you hit get alt enter actions to fix it. 00:13:32.460 --> 00:13:33.920 So you don't even have to run the client 00:13:34.020 --> 00:13:35.160 or the GitHub thing and so on, 00:13:35.420 --> 00:13:38.220 which the code spell has no editor integration. 00:13:38.760 --> 00:13:40.720 So it's really the fact that this is like that, 00:13:41.000 --> 00:13:43.440 a little better, runs in editors. 00:13:43.900 --> 00:13:44.320 That's cool. 00:13:44.600 --> 00:13:44.720 Yeah. 00:13:44.980 --> 00:13:46.280 Actually, I don't remember the last time 00:13:46.280 --> 00:13:48.600 I actually ran a spell checker independently. 00:13:49.000 --> 00:13:51.580 I just rely on those in-editor things. 00:13:52.180 --> 00:13:52.660 So do I. 00:13:53.220 --> 00:13:53.680 So do I. 00:13:53.800 --> 00:13:57.940 So yeah, it's also got LSB for other things, I guess. 00:13:58.600 --> 00:14:03.960 Yeah, that means you can even use it in NeoVim or Vim or Zed or whatever, right? 00:14:04.030 --> 00:14:06.080 So it's not just even the extensions. 00:14:06.660 --> 00:14:09.000 It's actually because the LSP even goes farther than that. 00:14:09.240 --> 00:14:09.420 Cool. 00:14:09.720 --> 00:14:09.800 Yeah. 00:14:10.120 --> 00:14:13.700 Anyway, thank you, Sky, for the follow-up and good suggestion. 00:14:14.020 --> 00:14:14.380 All right. 00:14:15.280 --> 00:14:18.440 Apparently, I'm missing having a testing podcast. 00:14:18.960 --> 00:14:23.780 So I've got two topics that I'd like to talk about, a couple of testing topics. 00:14:24.520 --> 00:14:25.380 First one came in. 00:14:25.560 --> 00:14:26.540 It's called Slowlify. 00:14:26.880 --> 00:14:27.960 It came in from Brian Skin. 00:14:28.260 --> 00:14:32.880 So thank you, Brian, for sending in this idea. 00:14:33.540 --> 00:14:35.540 So here's an interesting idea. 00:14:35.640 --> 00:14:42.940 So this is a project to simulate overloaded, slow, resource-constrained machines. 00:14:43.600 --> 00:14:47.720 So basically to make your tests flakier or something. 00:14:48.120 --> 00:14:49.120 Nice flaky tests. 00:14:49.900 --> 00:14:55.640 But the idea around it is a test is working fine locally, 00:14:55.940 --> 00:14:58.900 but you throw it up in CI and it fails for some reason. 00:14:59.300 --> 00:15:05.340 And it might be because you've got a CI image that is more constrained. 00:15:05.680 --> 00:15:10.820 So this allows you to do things like muck with how much memory is around 00:15:11.280 --> 00:15:14.360 and how many CPUs are available and stuff. 00:15:14.600 --> 00:15:21.880 It requires you to run it on a Linux machine with Cgroups V2 around 00:15:22.180 --> 00:15:24.940 because that's how it throttles the CPU and memory and stuff. 00:15:25.360 --> 00:15:28.500 But it shouldn't be hard to come by, hopefully. 00:15:29.080 --> 00:15:34.480 And yeah, then you can check to muck with things to find out, 00:15:35.100 --> 00:15:38.260 to try to simulate locally a failure that's happening in CI. 00:15:38.660 --> 00:15:39.520 So really nice there. 00:15:40.500 --> 00:15:44.280 The other topic I'd like to talk about testing-related is, 00:15:45.250 --> 00:15:46.660 this comes from Ned Batchelder. 00:15:47.380 --> 00:15:51.320 Actually, it's his article, Why Your Mock Breaks Later. 00:15:52.339 --> 00:15:55.200 And actually, I think it should be stronger than this. 00:15:55.240 --> 00:16:03.460 basically don't the don'ts and do's of uh mocking and the gist of it is uh overly aggressive 00:16:03.720 --> 00:16:09.200 mocks can can work fine at first but then break later recently a lot of people were doing uh 00:16:09.640 --> 00:16:15.720 all this pop down if you've like let's say you're reading a file and you want you want to pat you 00:16:16.000 --> 00:16:19.780 when the file gets opened you don't really actually want to file the muck with the file you 00:16:19.780 --> 00:16:25.660 want to be able to to mock that or patch it so one of the things that some people do is to patch the 00:16:25.820 --> 00:16:32.240 open function and one of the ways people do it is patching built-ins open this is not how you want 00:16:32.240 --> 00:16:38.040 to do it this is the don't do this version and uh let's just zoom in a bit don't do the built-ins 00:16:38.160 --> 00:16:45.759 open because it it like patches everything and it's causing problems in uh it was causing problems 00:16:45.800 --> 00:16:51.420 of coverage because coverage also wants to open something and you're basically patching open for 00:16:51.760 --> 00:16:56.440 everything in your app in your program including coverage when it's running on top of it so you 00:16:56.560 --> 00:17:02.420 don't want to do that you only want to patch where where you are so the proper way is wherever 00:17:02.840 --> 00:17:09.000 like if you're in a the example is you've got a user um file you want to patch right there in my 00:17:08.959 --> 00:17:12.680 product.user, the dot following of where it is. 00:17:13.020 --> 00:17:13.860 Exactly where it is. 00:17:15.220 --> 00:17:16.620 That's the gist of it is, 00:17:17.780 --> 00:17:20.380 don't mock the thing you're importing 00:17:20.990 --> 00:17:22.500 after you've imported it, mock it there. 00:17:22.900 --> 00:17:24.360 And it's a good lesson. 00:17:24.709 --> 00:17:25.740 I didn't think that this, 00:17:26.040 --> 00:17:29.620 I thought that was fairly widely known, 00:17:29.810 --> 00:17:31.560 so I didn't realize it was an issue. 00:17:31.870 --> 00:17:36.000 He went ahead and did a search for Python. 00:17:37.260 --> 00:17:49.660 In GitHub, you can search for built-ins open with tests in there and patches and stuff, either patches or whatever, monkey patching or patching or mock patching. 00:17:49.940 --> 00:17:54.560 Found 44,000 files that were doing the bad one within GitHub. 00:17:54.860 --> 00:17:57.460 So this is all naughty. 00:17:57.560 --> 00:18:07.500 I don't know what kind of GitHub badge you get for 44,000 PRs getting accepted, but Ned's got himself a real opportunity here to get a 100% sort of badge. 00:18:07.500 --> 00:18:09.700 I don't think he wants to fix them all, but yeah. 00:18:10.300 --> 00:18:12.660 No, that's an interesting way, an interesting metric. 00:18:12.980 --> 00:18:20.940 Yeah, and actually at the end of the article, also I'd like to point out, he talks about some mocking practices. 00:18:21.520 --> 00:18:26.680 Make sure you use autospec equals true to make sure that your mocks strictly behave like the original. 00:18:27.180 --> 00:18:29.620 I wholeheartedly agree with that. 00:18:30.220 --> 00:18:32.280 Make assertions about how your mock is called. 00:18:32.440 --> 00:18:35.940 Actually, the rest of this is stuff that I actually want to go check out 00:18:36.100 --> 00:18:39.120 because I do remember this functional core imperative shell talk 00:18:40.040 --> 00:18:42.040 and some of these other things, dependency injection. 00:18:42.280 --> 00:18:45.020 I'm not sure if I agree with all of Ned's stuff, but that's all right. 00:18:45.440 --> 00:18:47.920 Some other interesting things to read about with mocking. 00:18:48.340 --> 00:18:52.240 And I imagine he knows more than I do because I don't usually mock. 00:18:52.460 --> 00:18:53.380 I don't mock very much. 00:18:53.740 --> 00:18:55.020 It's not very nice to do, honestly. 00:18:55.380 --> 00:18:56.260 It's not very nice. 00:18:56.840 --> 00:18:59.880 So yeah, but sometimes it's necessary. 00:19:00.180 --> 00:19:01.200 And sometimes it's necessary. 00:19:01.540 --> 00:19:02.260 You know what is nice, though? 00:19:02.420 --> 00:19:02.700 Extras. 00:19:03.180 --> 00:19:03.860 Extras, yeah. 00:19:04.200 --> 00:19:05.320 Yeah, I do have extras. 00:19:05.500 --> 00:19:06.580 Should I go ahead and run through them? 00:19:07.220 --> 00:19:07.400 All right. 00:19:07.680 --> 00:19:09.420 So I've already got my stuff up. 00:19:09.640 --> 00:19:10.100 Let's go. 00:19:10.760 --> 00:19:15.300 This is a great, there was a great mini documentary of FastAPI, 00:19:16.540 --> 00:19:18.960 The Rise and Fall, Rise and Rise, not The Rise and Fall, 00:19:19.060 --> 00:19:22.880 The Rise and Rise of FastAPI with Sebastian Ramirez. 00:19:23.880 --> 00:19:25.960 And it's like an eight-minute video. 00:19:26.320 --> 00:19:28.800 It's a really fun video of him talking about it. 00:19:29.280 --> 00:19:32.200 He's such a genuine, nice dude also. 00:19:33.100 --> 00:19:34.460 Yeah, he really is. 00:19:35.360 --> 00:19:40.020 I am still writing, Lean TDD, the e-book in progress. 00:19:41.200 --> 00:19:42.880 You go to the table of content. 00:19:43.100 --> 00:19:44.320 Oh, I made a couple of changes. 00:19:44.780 --> 00:19:47.760 So somebody requested that not only do I, 00:19:48.080 --> 00:19:50.780 when I release a new chapter to release the full thing, 00:19:51.240 --> 00:19:52.620 but also the latest one. 00:19:52.780 --> 00:20:05.380 And that way people can just like just throw the latest one on their Kindle and just have one chapter where they can either replace the whole thing or if they've taken notes on other stuff to just do the updates, the new chapters. 00:20:05.660 --> 00:20:08.280 So I'm going to do that now or at least have started. 00:20:08.590 --> 00:20:10.740 We'll see. It's a little extra work, but that's all right. 00:20:11.580 --> 00:20:16.820 I got the building on lean done and it was long enough to talk about lean. 00:20:17.020 --> 00:20:19.820 I think that it made sense to split it. 00:20:20.060 --> 00:20:25.580 And I was going to do finding waste in test-driven development as part of that chapter, but I'm going to make it its own chapter now. 00:20:25.800 --> 00:20:26.720 So I'm going to do that. 00:20:27.120 --> 00:20:28.320 I wanted to do a sneak peek. 00:20:28.600 --> 00:20:29.400 Oh, never mind. 00:20:30.179 --> 00:20:33.380 Of the table of contents in progress so far. 00:20:33.560 --> 00:20:35.020 So I'm making some good progress. 00:20:35.140 --> 00:20:37.140 I've got an outline for where I'm going in the future. 00:20:37.800 --> 00:20:38.460 Where are we now? 00:20:39.080 --> 00:20:41.940 We're going to do finding waste in TDD next year. 00:20:43.039 --> 00:20:44.660 It's not going to be a huge book. 00:20:45.080 --> 00:20:45.860 Probably, I'm guessing. 00:20:46.020 --> 00:20:48.720 So right now we're up to, what, 30 pages? 00:20:49.640 --> 00:20:50.520 is a PDF. 00:20:51.740 --> 00:20:53.900 I'm guessing it will be under 100 pages when I'm done. 00:20:54.160 --> 00:20:55.920 So it's not a huge book, but it's also not expensive. 00:20:56.160 --> 00:20:56.420 It's $10. 00:20:57.200 --> 00:21:02.360 At least my experience is PDFs usually have more content per page than e-books, 00:21:02.940 --> 00:21:05.060 at least if you ask Amazon how many pages is it. 00:21:05.700 --> 00:21:08.060 Yeah, and even like way more. 00:21:08.400 --> 00:21:11.600 Yeah, it's more content per page for e-book, but also per print book. 00:21:11.940 --> 00:21:15.060 So print book isn't usually an 8.5 by 13 page. 00:21:15.410 --> 00:21:15.640 So yeah. 00:21:16.800 --> 00:21:22.840 Last one, my extra Python 3.14.2 was released December 5th. 00:21:24.059 --> 00:21:26.740 We haven't had 3.14 around for that long, 00:21:26.920 --> 00:21:29.340 but people are upgrading, which is great, 00:21:29.660 --> 00:21:30.840