---
title: Basic rspec Ruby on Rails model specs
slug: basic-rspec-ruby-on-rails-model-specs
published_at: 2021-07-12 14:00:20 +0000
updated_at: 2026-03-04 20:14:06 +0000
summary: 
description: In this episode you&#39;ll learn some basics for testing simple methods on Ruby on Rails models. #rails #rubyonrails
tags: [RSpec basics for Ruby on Rails, Ruby on Rails unit tests, Unit testing, Model test, Unit test, Model spec, model specs, ruby on rails tutorial, rails tutorial, beginner rspec tests, rspec for beginners]
views: 18866
author: CJ Avilla
url: https://www.cjav.dev/videos/basic-rspec-ruby-on-rails-model-specs
youtube_url: https://www.youtube.com/watch?v=Spogv4o8haM
youtube_id: Spogv4o8haM
embed_url: https://www.youtube.com/embed/Spogv4o8haM
thumbnail_url: https://i.ytimg.com/vi/Spogv4o8haM/hqdefault.jpg
type: video
---

# Basic rspec Ruby on Rails model specs

*Published: July 12, 2021*
*Views: 18866*

## Watch

[Watch on YouTube](https://www.youtube.com/watch?v=Spogv4o8haM)

[![Basic rspec Ruby on Rails model specs](https://i.ytimg.com/vi/Spogv4o8haM/hqdefault.jpg)](https://www.youtube.com/watch?v=Spogv4o8haM)

## Description

In this episode you&#39;ll learn some basics for testing simple methods on Ruby on Rails models.
#rails #rubyonrails

## Transcript

hey what&#39;s up welcome back in the last two episodes you learned how to set up rspec rails and then set up factory bot which are two tools for helping with testing again we&#39;re kind of going through the process of trying to make some content here for sean mcgom about r-spec and r-spec test for both the controller and the model and we&#39;re working our way up from just kind of setting up the test framework and oftentimes that can be sort of the most tedious part is just getting everything set up so that it runs and then once you have sort of a framework in place and your generators in place it can it can be much easier to actually do the right thing and sort of uh implement tests so now that we have some testing set up in our application what i wanted to do is just write some very simple model tests so here we have in our app models directory a lot of these models are basically just like models that are wrapping up database fields but we don&#39;t have any logic written in ruby so for example like a form 4 transaction it has all this data but we don&#39;t actually write any methods inside a form for transaction so there there are many here that don&#39;t have anything other than just association so we have a company form four though is one that&#39;s quite interesting we have a handful of methods in here letting us know whether or not we should sort of notify based on this again we&#39;re building a form for tracker for sec filings that um are required filings by people who are considered insiders by the security and exchange commission in the united states and this is going to tell us whether or not um it tells us about traits that they&#39;ve made in their own companies and then we try to like look through some of that data to to figure out if it might be interesting for us to trade the the same um the same stock and so we have some methods here whether or not we should notify and this one in particular says like if the form 4 was a buy so did they buy some shares were they a leader in the company so we defined leader as just kind of this like regular expression and then is the number of shares um changing the total holdings by more than five percent it says five percent in the comment but really it&#39;s ten percent and so this method here is doing a handful of different things we also have some helpers down here for the percent that it is changing in their holdings whether or not they&#39;re a leader and whether or not they should buy and so what i want to do is go through and write some tests for each of these methods that we can run i have we have we don&#39;t actually have a spec for this model yet so in uh in spec models there will be a formspec.rb instead of writing that manually we can say okay so we should be able to say rails g r spec colon model for form four and this will create the model spec for us this is if you have existing models that don&#39;t have r-spec files created for them when you are first starting out and you don&#39;t necessarily need to do this you could just go and create the file by hand but i like to do it this way because it creates both the spec file for us and also the factory for us so now if we head over to our form 4 spec you&#39;ll see that we have a pending test here okay that&#39;s great and then we also have a factory for form force so this form for factory doesn&#39;t have any fields in it but we might want to go and set up a bunch of fields based on our our test the other thing too that i&#39;m using here with vim is the vim rails plug-in so let me show that in my vmrc.bundles vim rails so i&#39;m using this this plug-in by t-pope this is pretty handy for moving around different files so i can say like i can hover over form 4 here and say gf and that will jump into the model file um i you can also say like colon a so it says like give me the alternate from this test file so that if you&#39;re in a controller spec it&#39;ll jump to the controller if you&#39;re in a model spec we&#39;ll jump to the model um so that can be that can be pretty handy all right so let&#39;s actually write some tests based on this form four so i&#39;m gonna pull up the form four model and the very first one that we might wanna do is buy just like how what does it mean for a form four to buy so now we&#39;re going to say it correctly derives if it&#39;s a buy now we want to say form 4 is equal to create colon form for and we want to specify the the some shares so this is the thing that we want to pass in when we&#39;re creating our model so that&#39;s the one thing that we want to control because that&#39;s the one thing that&#39;s being used as part of our method here um and we can say sum shares is like one okay and then we would say expect form four dot two b and we can actually just say to be buy because buy is a method that ends in a question mark and so this is just a shortcut so i&#39;m going to use my command h is my leader key when i&#39;m using vim test to quickly run this spec and what we&#39;re seeing here is we have an active record validation failure because the company and the insider must exist so when we&#39;re creating a new instance of a form 4 it belongs to a company and it belongs to an insider so the factory that was created for us so form for&#39;s factory this needs to have a company and it needs to have an insider so now if we ran this test again it&#39;s going to fail because we don&#39;t have we don&#39;t actually have factories for companies or insiders yet so we kind of need to do a little bit more legwork here so let&#39;s again say rails g r spec model for our company and same thing for insider this will create the factories for a company in the factories for an insider which we can then use inside of our form 4 factory so we go back to our form for spec and rerun this test all right so now we&#39;re getting a null constraint because the column cik violates that null constraint so as part of creating a company we need to pass in the cik so now we can go to our company&#39;s factory and make sure that the cik field is populated let&#39;s also just go to um the company model and see if there&#39;s any other that are non-null okay so we need an id we need a cik and this is going to be potentially we could just make this a sequence of cik and we&#39;ll say uh n and then we&#39;ll just say we&#39;ll return this string like cik dash and then the number there and that will create a company object that has a cik that is uh sequenced for every single time we create a company i&#39;ll just create once cik1 cik2 cik3 etc so that&#39;s the only that&#39;s the only field that is non-nullable and i think this should work fine if i spell sequence correctly all right so now we have our first passing test but it&#39;s bad if we start off with the test passing because we want the test to fail we want the test to fail so in order when you&#39;re writing tests it&#39;s very important to make sure that the test is failing because if the test passes out of the gate it could be that you wrote your test incorrectly or it could be that your code works perfectly so in order to isolate and make sure that your code is working perfectly what i like to do is first go into the code that i&#39;m running the test for and actually comment the entire thing out and then i&#39;ll run my test and i want to work forward and sort of solve each of these smaller uh these smaller failing expectations so here this first this first error is saying that like it expected this giant form object to respond to by question mark and it didn&#39;t so now we can comment in that method right and that will make it so that we know for sure that we&#39;re calling the right method and we want to see the error message change so we want to just keep seeing the error message change so here we see i expected it to be truthy but we got nil okay so we&#39;re making progress now we can comment this in and now we should see our test i believe pass here um okay but ensuring that it is a buy while some shares is positive is only half the test right so we also need to create another form four and in this case we&#39;ll pass in as some shares of negative one and and then we want to make sure that it&#39;s not a buy so not to be a buy so we can use the not i can&#39;t remember if it&#39;s not in front or behind or maybe they both work but these are the two things that i would probably run to test to make sure that buy is working successfully let&#39;s do another example here so leader so it um correctly uh it determines if if the insider was a leader so the the reason why we we calculate whether or not it was a leader as part of the form four is that an insider might be an investor in one company they might be the cfo of another company and they might be a ceo of a third company and so rather than tracking the officer&#39;s title on the insider itself we want to use the form 4 which is sort of a snapshot in time of when they traded and here in this case we want to control officer title so here we&#39;re going to say form 4 is equal to create form 4 where the officer title is maybe ceo and then we want to say expect form 4 dot 2 be leader and we can do this again for all of the different we might want to go through and just say like all of the different like officer titles that we consider to be um to be leaders the other way we could do this is actually by just creating a list of all the things that we want to test and ensure so we could say like ceo comma cfo comma like prez and then we can say dot each do title and so we can use we can use loops inside of our tests we don&#39;t necessarily need to write out every single thing hard coded right and so this can say like if the officer title is one of these title then we want to uh expect and ensure that it is a leader now if you imagine that like your as your application develops and grows this regular expression that we&#39;re checking to see if it&#39;s a leader or not might also grow pretty substantially right so like at first we&#39;re just sort of copying and pasting each of these different possible values and i&#39;m just gonna grab the rest of these to be like super complete um okay and then let&#39;s clean this up a little bit so the point that i wanted to make here was that if you&#39;re doing this sort of testing where you&#39;re going to run like a bunch of different string values this is one option to do it but there is a downside to using create because every single title here we&#39;re going to create a new form for save it in the database just so that we can call this b leader method right so if we say run this test we&#39;re going to say command h or leader h that&#39;s going to run my test and here we see that this took uh 3.3 seconds to load or whatever or this finished in you know an eighth of a second or whatever that is right and so one thing we can do is change this directly to build because our method our leader method does not require that this model is actually saved to the database we can actually do this up here also build and build and now when we run this test recall that last time it was .16 seconds to run the test now if we run the same exact test we get 0.14 it&#39;s only a hair quicker but uh yeah the files were like it&#39;s a large portion of it is being spent on loading the files but if you could imagine that like the bigger this list gets the more important it is to only create and persist things to the database that need to be persisted to the database in order for the assertions to be true or to you know succeed all right so i think we&#39;ve got uh whether or not it was a leader let&#39;s also put in some tests here that are not leaders so we can say like um i don&#39;t know director i think we have director as like a definitely like not a leader role but i&#39;m going to also use an array here and i&#39;m going to do the same or like the same process to not not to be a leader because uh in the in the future we might want to like make specific assertions about certain titles and make sure that they are not considered leader so we can we can start off with an array here and then add to it as we go along but we want to have at least one that is the inverse of what we&#39;re checking above okay let&#39;s do percent change now so percent change calls two methods it calls some shares and it calls some shares after and it does a little bit of division and then multiplies to figure out what is the percent that the holdings changed here so let&#39;s make another method so it&#39;s um has the right percent change due the the names of the tests here that i&#39;m writing are not very good but it&#39;s kind of yeah hopefully it&#39;ll give you an idea a rough idea of things things that you might test so here we want to create another form for we&#39;re going to say in this case again build because we don&#39;t actually need to persist this to the database form 4 and we want um we want to pass in in this case some shares and let&#39;s try to make this easy so let&#39;s say that they have 200 shares and the shares that they purchased um oh yeah so let&#39;s say that they&#39;ve they bought maybe 50 shares here and some shares after is 200 then we would expect uh form 4 dot percent change dot two equal um was that 25 and i think it&#39;s going to be like 25.0 because we&#39;re doing f div so let&#39;s just see if this works all right so we&#39;ve got another passing test now the other thing too is like every single time that you get a test to pass recall that we should probably comment out and then comment those back in so now we&#39;re we&#39;re to the place where we&#39;ve written leader and we&#39;ve written percent change so i&#39;m going to do command l rerun all the tests and then sort of comment those back in so our undefined method percent change let&#39;s comment that back in and then we&#39;ll run that again it&#39;s going to say percent change return nil instead of 25 okay let&#39;s comment that back in run it again all right now we have two passing tests now the issue is it&#39;s not responding to leader question mark so we&#39;ll comment that back in run the tests again again you want like a super fast feedback loop okay so expected to be truthy but we got nil so now let&#39;s comment this back in and all of our tests should now be passing fine um and we&#39;re the the amount of coverage that we have on this model is is pretty nice so the only thing that we have left here is should notify and so in here we should say like it um should only notify when by liter and percent change is greater than threshold okay so now we want to again create a form four where the percent change is greater than whatever our number is here if you if you&#39;re going to change or like or configure this percent change number you might want to also make this a constant so in this case let&#39;s say that like the percent change threshold is equal to 10 and then here we can use that constant that way we have access to this constant from our tests so we could even use that here um is greater than and then we can put in like uh i don&#39;t know like form four percent change threshold and now when we run the test it should actually like print out that title um uh we don&#39;t actually have any expectations here expect false to be true okay so now now our uh you can see that our message here form four should only notify when uh when buy leader and percent changes greater than 10. so 10 is actually like in the title here because it&#39;s using that constant and also our our method here is using the constant the nice thing about that is if we ever want to change this percent threshold percent change threshold we can just come in here and say like oh we actually want it to be 12 now and now our tests are going to depend on the constant and also our implementation is going to depend on the constant so we don&#39;t have to like go change both of them at the same time so let&#39;s let&#39;s do that now so let&#39;s say it is 10 and then what we can do as part of our expectation is we need to make sure that it&#39;s a buy it is a buy since it&#39;s greater some shares is greater than zero we need to set the title so officer title is ceo and we also need to make sure that the percent change is less than 100 if it&#39;s i just have this um this one setting where if they are buying 100 of their shares it&#39;s often they&#39;re getting their first grant or something and it doesn&#39;t really it&#39;s not very indicative of anything interesting so now we can say expect form 4 dot 2 b should notify that&#39;s uh yeah it&#39;s a little bit i mean maybe this should just be called like notify like that um whatever or notified and that might be yeah it might make a little bit more sense again we&#39;re gonna need to comment out our implementation and then run the code or run our tests we should see like oh it doesn&#39;t respond to should notify okay comment that back in run it again okay now it&#39;s expecting it to be truthy we can comment this back in and now we should be good to go um the other thing you might do is we want to we want to like now we need to make it fail for each of the individual forks in in the in the change so we could say like uh well one option here is that we can say like okay it should notify when it&#39;s each of these things it should not notify when it&#39;s a sell when it&#39;s a sale so it should not notify when sale so then here we can say like oh the sum shares is actually like negative 50. and we should accept expect it not to be okay all right that&#39;s going to pass immediately one thing we could do is actually comment out that part and see that it fails because it needs to check that it is a sale so the percent change is also negative so bi and percent change are uh are duplicative here but um that&#39;s fine i think percent change we should probably also make this um we could make percent change a absolute value but whatever this is kind of like how how i might do this the thing that i wanted to show was is not necessarily like how you write all these different tests but instead how you can uh how you can organize this so at this point we have writ we have like just a handful of methods in this model right should notify percent change leader in pi and to up to this point we&#39;ve sort of put in in this first case we put correctly derives if it&#39;s a buy and we executed two different assertions in the same it block so in practice you probably want to have only one assertion um or sort of only be checking one use case so it can actually be a little bit better to just say like uh it um correctly you know or like it knows if it&#39;s a sale and have these be separate have these be separate it blocks that are part of your test suite so that you can isolate very specific use cases and flows control flows so you don&#39;t have to like sort of guess which one you&#39;re going down now as soon as you start breaking up your it blocks so that you have several per method right so for this one buy method we now have two different it blocks what you can do is you can organize those under sub describe block so what let me show you what i mean so i can hear say describe by question mark do and then i can put end down below and now it&#39;s going to nest this method inside the other thing you might do is put like pound sign that&#39;s to sort of say that this is an instance method instead of a class method um and right now our right our our output our r spec output is just doing dots we can also configure that to to show like a more verbose output with more details about our our method so let&#39;s do that so format format progress that&#39;s i think the default dash dash let&#39;s try format documentation and then we can just run this again let&#39;s see if it okay here we go so this is this is a little bit more uh detailed output from your from every single test run now you it depends it&#39;s kind of like a personal preference if you want to just see dots across the screen or if you want to see full output with all the details for now it can be handy to see this organization in the documentation format so we&#39;ve got form four and then under the form forward these two specs are about the buy method so similarly we can organize these under like describe the um officer or like leader method right and that&#39;s again we would probably split this into two different it blocks one that&#39;s checking if it is a leader one is checking if it&#39;s not a leader and then down here below we have should notify so we&#39;ll describe should notify do and similarly with our um if we&#39;re testing inside of a controller or something we would want to say like each of the different routes so now this should be organized really well underneath some some sort of names that are organizing the tests for each of the methods that we wrote all right so now we can see all of these are right this one we didn&#39;t organize under anything special yet but you can kind of see the as as uh the output is now documenting as uh each it&#39;s documenting how the form 4 works so this can be like a nice way to to see the output all right i think that&#39;s probably good enough for the form 4 method it&#39;s also giving us a scaffold that we could just easily drop into if we wanted to add more functionality to form 4 change it in some way we could quickly update the tests and assert that changes that are happening to our form 4 model are working as expected all right so that&#39;s how i would go about testing some really basic methods inside the model that are sort of helper methods for deriving certain things about the about the data that&#39;s in the database in this in the next video we&#39;ll go into some more complex testing for models and we&#39;ll talk about um yeah how we tested a couple other features of this application thanks so much for watching and we&#39;ll see in the next one

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