I am starting in node.js unit testing, and I have been investigating which was the most used framework for unit tests in node.js. I'd like to start with the most used framework just to makes things easier as there might be more information about it. According to many sites that could be Mocha.
While I understand this module for doing integration tests I don't really know how to work with it by using feautures like stubbing dependencies. I have seen mocha doesn't provide mock/stub functionalities, so I don't really know how people usually deal with these problems.
So I'd like to know what modules are the most popular nowadays for doing unit tests, stubbing dependencies... A short example would be great.
Thanks
The current suite of modules combined together in many node.js projects seems to be:
Mocha for the actual test harness itself
Chai for assertions
Sinon for mocking/stubbing
All of these work both in node.js as well as the browser, which is important to many people including myself. There are many choices available as you might expect, although when it comes to mocking and stubbing I believe Sinon is clearly the current popular choice.
Here's a small example in coffeescript that uses all of these libraries. It tests that when you fill in the sign in form and submit it, your info is passed to the API properly.
describe "UserSignInView.signIn", ->
it "should submit the user credentials", ->
sinon.spy _OT.api, "sendJSON"
testUser =
email: "test.user#othenticate.com"
password: "password"
$("#OT_signInForm .OT_email").val(testUser.email).change()
$("#OT_signInForm .OT_password").val(testUser.password).change()
$("#OT_signInForm .OT_signInButton").click()
assert.ok _OT.api.sendJSON.called
credentials = _OT.api.sendJSON.lastCall.args[0]
assert.equal credentials.email, testUser.email
assert.equal credentials.password, testUser.password
options = _OT.api.sendJSON.lastCall.args[1]
assert.equal options.url, "/othen/users/authenticate"
assert.isDefined options.error
assert.isDefined options.success
Related
How do you write unit tests for Htmx?
Stack overflow isn't letting me post such a short question, so this paragraph says that I didn't see docs or a library about this.
EDIT: Specifically, I wish to unit test in Django.
There are a couple of solutions to this:
Many server side platforms offer the equivalent of rails "functional" controller tests, and those can be used to test your partial end points, depending on what platform you are using.
You can write client side javascript tests in the normal manner. The htmx test suite uses chai.js & mocha.js to create a test suite, and sinon.js to mock out the server side. If you can run the tests against your actual server, that will simplify things even more.
Broadly, for day to day unit tests, I would lean towards the first approach because it will be more stable and "functional" and then use the second approach for integration testing.
I guess you use some kind of framework. For example Django, Laravel, Ruby on Rails, ...
Just use the tools of your framework to test your http endpoints.
For e2e tests I would use Playwright. But keep in mind this rule: 80% unittests, 15% integration tests, 5% e2e tests.
I have one e2e test which checks to happy path.
And a lot of pytest-django based tests.
For forms I use this pattern: html_form_to_dict
Maybe this question gets better answers in the discord channel, since there is no clear answer.
I read a lot about unit testing and integration testing, and the unit testing part I understand fairly well - isolate the object under test, and mock out dependencies using interfaces and inject those. (Or use seams to inject testable behavior).
However something that is still a mystery to me even after searching is integration testing. Every blog and link talks about testing various components together, do's and dont's, CI Servers, etc, but there's not much explanation in the way of how this is to be done.
Is an integration test automated? Or is this a manual effort? If it is automated, do I write this as code in the native language my app is in? How do I check or verify if the integration test is working as expected?
For example, if I have 4 services (a Socket Client, a Socket Server, a Database, and a Web Application) and I want to do some integration testing on how these 4 services interact with each other. How exactly how would I approach this? I know that some dummy data will be involved, but which part of my integration test is checking if the systems are working together correctly? This part is really unclear to me.
As you said about unit testing, you need to isolate the object under test, and mock out dependencies using interfaces and inject those...
Integration test is without isolating the unit... You can test two part or more (but you shouldn't have extensive integration test suits neither big test scenario). An example of integration test is testing your code with the database, you could need for that to initiate the database and clean it to have a repeatable tests.
You could have as well interface test (client execution and integration with the server for example) and so on.
Don't forget that this tests come with a downside, they are slower and harder to maintain, but they have different purpose than unit test, which is checking that units works as expected with real dependencies.
So to wrap-up if you write a test without totally isolating the unit it is an integration test, due to its nature it's better to test the logic of your code by unit test and reserve fewer integration tests when needed to test the interaction between the units.
You can also check this nice introduction https://softwareengineering.stackexchange.com/questions/48237/what-is-an-integration-test-exactly
An interesting definition from "the pragmatic programmer": integration tests show that the major parts of a system work well together
Recently,I am studying about django test. Because I need to build unittest and integration test in my website.But I find that the tutorial of integration test in django is really less and it often occurs when I hit a link named "integration test" ,I only see the title "functional tests".So,are they the same? if not,how can I start a integrstion test in django?
You cannot compare these notions.
The opposite to integration testing is unit testing. Unit testing - is testing different isolated parts (usually small code blocks) of your system separately - it's very focused, integration testing is testing how these different parts of your system work together - for example, url routing, logic in views, logging, querying your models etc.
Functional testing is a type of black box testing that usually checks that some (usually documented) piece of functionality works as expected.
You may have all sorts of tests in your django project:
unit tests of different library, helper functions
view tests (this could be already called integration tests, because it may include dealing with models, logging etc)
ui tests (high-level tests, that could be called functional/integration/system)
..
If you don't have tests at all, I'd start with high-level tests. For example, I'd take selenium and django_selenium and write some in-browser tests that will go through pre-defined scenarios, like login->do smth->logoff, login with incorrect credentials->see error etc - and these tests would be called functional and system and integration and ui and etc - you got it I think.
See also:
Testing Django Applications
A Guide to Testing in Django
Carl Mayer's "Testing and Django" slides
Integration Testing in Python
Hope that helps.
Upon reading Growing Object Orientated Software Guided by Tests, I learnt of test isolation and test fragility. The idea that each test should be very specific to a piece of code or functionality, and the overlap of code coverage by tests should be kept to a minimum.
The implied ideal that each change in the code should result in breaking only one test.
Avoiding spending time going through multiple broken tests to confirm that one change is the cause and if it is fixed by the test modifications.
Now this seems easy enough for unit tests, they are very isolated by their nature.
However when presented by integration tests, it seems hard to avoid having multiple tests exercising the same code paths, particularly when run in addition to the unit tests.
So my question, is what dependencies should be mocked when doing integration testing? Should anything be mocked at all? Should a single execution path be tested, and all side effects not directly relevant to this code path be mocked?
I'm toying with the idea of doing pairwise integration testing. Test one relationship between two objects, and mock everything else. Then changes in either one of these objects should have minimal impact on other integration tests, in addition to forming a complete chain of end-to-end tests by means of pairs.
Thanks for any info..
Edit: Just to clarify, I'm basically asking "How do I avoid large numbers of failing integrations tests during the normal course of development?". Which I assume is achieved by using mocks, and why I asked about what to mock.
Update: I've found a very interesting talk about Integration tests by J.B.Rainsberger, which I think answers this fairly well, if perhaps a bit controversially. The title is "Integration Tests are a Scam", so as you can guess, he does not advocate Integration Tests at all (end to end type tests). The argument being that Integration Tests will always be far below the amount needed to thoroughly test the possible interactions (due to combinatoric explosion), and may give a false confidence.
Instead he recommends what he calls Collaboration Tests and Contract Tests. It's a 90 min talk and unfortunately the whiteboard is not very clear and there aren't code examples, so i'm still getting my head around it. When I have a clear explanation I'll write it here! Unless someone else beats me to it..
Here's a brief summary of Contract Tests. Sounds like Design by Contract type assertions, which I believe could/would be implemented in a Non-Virtual Interface pattern in C++.
http://thecodewhisperer.tumblr.com/post/1325859246/in-brief-contract-tests
Integration Tests are a Scam video talk:
http://www.infoq.com/presentations/integration-tests-scam
Summary:
Integration tests are a scam. You’re probably writing 2-5% of
the integration tests you need to test thoroughly. You’re probably
duplicating unit tests all over the place. Your integration tests
probably duplicate each other all over the place. When an integration
test fails, who knows what’s broken? Learn the two-pronged attack that
solves the problem: collaboration tests and contract tests.
For integration tests you should mock the minimum amount of dependencies to get the test working, but not less :-)
Since the integration of the components in your system is obviously the thing you want to test during integration testing, you should use real implementations as much as possible. However, there are some compontents you obviously want to mock, since you don't want your integration tests to start mailing your users for instance. When you don't mock these dependencies, you obviously mock too little.
That doesn't mean btw that you shouldn't allow an integration test to send mails, but at least you want to replace the mail component with one that will only send mail to some internal test mail box.
For integration tests I lean towards mocking the service rather than the representation for example using mirage instead of a 3rd party REST API and Dumpster rather than a real SMTP server.
This means that all layers of your code are tested, but none of the 3rd parties are tested so you are free to refactor without worrying that the tests will fail.
Unit tests should have mock objects, but integration tests should have few if any mocks (otherwise what is being integrated ?) I think it's overkill to do pairwise mocking; it will lead to an explosion of tests that might each take a long time and lots of copy and paste code which will be a pain to change if requirements change or new features are added later.
I think it's fine to to not have any mocks in the integration tests. You should have everything mocked in the unit tests to know that each individual unit works as expected in isolation. The integration test tests that everything works wired together.
The discussion of Contract/Collaborator test pattern (described by JB Rainsberger in "Integration Tests are a Scam" mentioned in the question above). Relating to the question here - I interpreted his talk to mean that when you own the code for both the service side and the client side, then you should not need any integration test at all. Instead you should be able to rely on mocks which implement a contract.
The talk is a good reference for high level description of the pattern but doesn't go into detail (for me at least) about how to define or reference a contract from a collaborator.
One common example of the need for Contract/Collaborator pattern is between an API's server / client (for which you own the code of both). Here's how I've implemented it:
Define the contract:
First define the API Schema, if your API uses JSON you might consider JSONSchema. The schema definition can be considered the "Contract" of the API. (And as a side note, if you're about to do that, make sure you know about RAML or Swagger since they essentially make writing JSONSchema APIs alot easier)
Create fixtures which implement the contract:
On the server side, mock out the client requests to allow unit testing of the requests/responses. To do this you will create client request fixtures (aka mocks). Once you have your API defined, validate the fixtures against the JSONSchema to ensure that they comply. There are a host of schema validators - I currently use AJV (Javascript) and jsonschema (Python), but most languages should have an implementation.
On the client(s) side you will likely mock out the server responses to allow unit testing of the requests. Follow the same pattern as the server, validating the request and response fixtures via JSONSchema.
If both the Client and the Server are validating their fixtures against the contract, then whenever the API Contract changes, the out of date implementations on both sides will fail JSONSchema validation and you'll know it's time to update your fixtures and possibly the code which relies on those fixtures.
I have been doing a lot a reading about unit testing.
Unit testing seems all well and good.
But it seems to miss a lot of the fundamentals of how the web works. User Interaction.
I have not seen any way a unit test could test for unexpected input, or test to make sure that an ajax call works etc.
Am I missing something here or is unit testing not really designed well for web development?
You are not missing anything.
Ideally unit testing is about testing a small piece of code, e.g. a class in isolation. For this you may want to use a unit testing tools such as JUnit or NUnit. Some people refer to this type of tests as developer tests.
In contrast to that you may want to test web applications as a whole. Some call this acceptance testing. For the latter you could use a tool such as Selenium. Tools like Selenium can test Ajax and other JavaScript as well.
You have even more options if you take a look at a tool like WebDriver as you will find that you can implement Selenium-based tests using a unit testing tool.
Take a look at Selenium.