Angular component testing example The Angular CLI downloads and installs everything you need to test an Angular application with Jasmine testing framework. Typical candidates are HttpClient, ActivatedRoute. Using @ngrx/store is common practice in Angular applications, so everyone finally have to test component with Store. Services often depend on other services that Angular injects into the constructor. for example getCustomer only. Example: CalculatorService 6 days ago · Standalone components give you a better foundation to build on, as your Angular component becomes less affected by its internals. Dec 5, 2016 · Testing Examples Testing a Component. Custom stepper using the CdkStepper Create a custom stepper components using Angular CDK. Mar 6, 2025 · This Angular Component Testing with Jest tutorial provides a step-by-step guide on setting up Jest for testing Angular components. overrideComponent function, passing add and remove instructions for providers or viewProviders. Sadly, not all 3rd party components have test harnesses but if needed you can write your own. Angular component testing is an important part of Apr 25, 2020 · I have recently started using JEST with Angular and I was not able to find a clear example, so want to share here so it can be helpful for others. Testing pipes—find out how to test attribute directives. In the next test, we'll see how to use the MockStore in a component test. For a standalone component, it means all its imports. arrow_upward_alt Back to the top Set up testing. This ensures compatibility with JSDOM Apr 25, 2023 · To recap, the integration test includes (“integrates”) the dependencies. Component testing can be performed on an application that uses any modern framework such as Vue, React, and Angular. ts Mar 4, 2025 · Here’s an example of how to test a WeatherService. Harnesses (Angular Material Testing) — For testing The @testing-library/angular is a very lightweight solution for testing Angular components. How to set up Component Testing for React, Angular, Vue, or Svelte; and the second parameter is a function that contains the test code. Angular test. Configuration updates. Mar 21, 2025 · Using Playwright with Angular. The TestBed. It demonstrates how to properly mock dependencies like Services to test a Component in isolation. The goals of this example are: Simplicity: Quickly grasp what the Component is supposed to do. When you launch Cypress for the first time, the app will ask you whether you want to set up component testing or E2E testing. Mar 10, 2022 · A unit test typically focusses on a single Angular Component, Directive, Service, Pipe, etc. Component testing scenarios. But before you must understand the principles behind testing. The guide introduces the Spectator and ng-mocks libraries, two powerful testing libraries. The purpose of the spec is to test the component, not the service, and real services can be trouble. Using Jest to test Angular Component. As the CounterService always starts with the count 0, the test needs to take that for granted. In many cases, it is easy to create and inject these dependencies by adding providedIn: root to the injectable object, which makes it accessible by any component or service: Oct 11, 2019 · I am writing unit test for angular app, I am testing if the service function returns a value. The application we will test is the final step from the official Angular tutorial Tour of Heroes. TestBed; createComponent; ComponentFixture, DebugElement, and query(By. Here, we are testing the component class. Testing components is a crucial part of Angular testing. debugElement. Meanwhile, the ng test command is watching for changes. Jun 16, 2021 · cd angular-unit-test-example; Alongside the app. The component testing needs the application code to be present locally on the machine. We need to mock them. Dependencies are set up. integration test dilemma again. Your framework—Angular in your case—is immediately detected by the Project Setup screen. May 15, 2018 · In this article we will look at some tips and techniques for doing unit and integration tests of Angular Components. Jan 8, 2025 · Angular component testing is a crucial part of ensuring that your Angular application is stable, maintainable, and scalable. 0 4. Because the component involves both the template and the TypeScript class, we need a way to control both in the test code. members: Name: Type: Description: autoSpyOutputs: boolean (optional) flag to automatically create a cy. Mar 29, 2023 · How to test an Angular service. It doesn't matter if the component has its own template, or if it's using child components. The AppComponent , for example, displays a navigation bar with anchors and their RouterLink directives. queryAll(By. Example 1: Testing an Angular Component Angular is a platform for building mobile and desktop web applications. This article revisits integrated routing component tests with modern Angular APIs, including standalone components, provideRouter, provideLocationMocks, and RouterTestingHarness. Open this file and examine its contents: Apr 14, 2023 · Test that the component renders with dynamic styles : In this section, we will be Testing that a component with dynamic styles renders in Angular involves verifying that dynamically generated CSS styles in the component's logic or templates are applied correctly when rendering the component this ensures that components look as expected and are Jan 17, 2023 · Click on a test row to re-run just that test or click on a description to re-run the tests in the selected test group ("test suite"). Thank you for reading and If you find this useful, please give Jul 23, 2023 · Of course, writing tests means using and learning tools like Jest or Angular specifics. 2. Tutorial Visit the Getting Started Guide for a step-by-step tutorial on adding component testing to any project and how to write your first tests. An easy way to initialize the Playwright tests in a project is to run: Click on a test row to re-run just that test or click on a description to re-run the tests in the selected test group ("test suite"). Let’s add some code in our todo-card. Jest — An alternative testing framework that is faster and provides better debugging. Tools and technologies; Setup; Isolated unit tests vs. ts: import { The component tree can be very deep and, most of the time, the nested components play no role in testing the component at the top of the tree. Then we start Angular’s change detection so the Component together with the Directive are re-rendered. Nov 5, 2024 · Editor’s note: This article was last reviewed and updated by Abiola Farounbi on 5 November 2024. To launch the configuration wizard, click “Component Testing”. Still, the main benefit is we can see the component on the screen and use Cypress debugging features such as time travel, screenshots, and video recordings of our tests. Component testing scenarios—read about the various kinds of component testing scenarios and use cases. spy() for every component @Output() property Aug 1, 2023 · For example, TestBed-based tests can be used for testing components with complex templates, testing interactions between components and services, and integration testing of Angular modules. Here, I'm going to present these APIs. 5. Jan 16, 2025 · A unit test is a test that focuses on a single unit of code, such as a component or a service. All these benefits, plus you'll see that it's fun to write tests in this way. For example, to include only tests called counter. Add them to your TestingModule's `imports` property, and all their "visual elements" – Components, Directives, Pipes Aug 26, 2023 · Photo by Iewek Gnos on Unsplash. However, it gets tricky when we want to mock the child component with a stub. See more examples. Testing. These replacements are also called test doubles, stubs or mocks. Testing Angular Services: Why Do It in the First Place? Let’s set the stage for why we even bother with testing Angular services in the first place. Read about best practices, or follow the guided example. These are classes, functions, objects, etc. spec) file by default. Angular has various kinds of tests: Unit tests: This kind of test focuses on testing small, isolated pieces of code, such as components, services, or pipes, without relying on external resources. As such, testing an Angular component involves ensuring that both parts are coupled as intended. using your approach. Mar 8, 2024 · The Angular Testing Library (ATL) was introduced as a valuable tool for component testing, mimicking user interactions as close as possible to real users. In AngularJS, a Component is a special kind of directive that uses a simpler configuration which is suitable for a The examples use the Jasmine testing framework. For the sample application that the testing guides describe, see the sample app. Hybrid Angular applicationslink AngularJS to Angular concepts: Quick referencelink. Jan 20, 2024 · Creating a Sum of Two Numbers Component and Test Cases {"jest_test_angular": setup files, and more. This brings more maintainability to our tests, gives us more confidence that our component does what it's supposed to do, and it improves the accessibility which is better for our users. Try out Cypress Component Testing using any example by cloning this repo, cding into an example directory, installing the dependencies, and running Cypress per that example's instructions. It explains how to configure Jest as a replacement for Playwright Angular component testing or Cypress alternatives and how to handle common challenges with complicated dependencies in the framework. We will face the unit vs. For example, you can test to verify that your app sends or receives the expected data from a service. Instead, Cypress component testing is added directly to a project, like Jest. example')); You can also filter by @Directive f Component harness authors are developers who maintain some reusable Angular component, and want to create a test harness for it, that users of the component can use in their tests. Refer to the Angular Testing Guide for detailed information on testing Angular applications. Please see here for a complete example, Unit Testing Angular Componentand Child Component; Unit Testing an Angular Custom Service. I have the following AppComponent. Here, we'll go through a basic service example and its tests. ts and save. Let’s take a simple component that renders a greeting message using an @Input() Unit Test in Angular Part 1. Arrange, Act, Assert. Arrange is the preparation and setup phase. Dependency Injection: TestBed manages dependency injection for you, making it easy to inject services and test their interactions. component. Oct 30, 2021 · The new Angular component will appear in its own folder. in this article angular component testing, we’ll demonstrate how to build a simple Angular app and then walk through the unit testing process step by step with examples. ts file. This makes your test cases less brittle than before with Angular Modules. Testing Components. Nov 5, 2021 · Once our testing module is configured we can then instantiate for example the component we want to test. This ensures that the component's template is available for testing. There are two fundamental ways to test Components with children: A unit test using shallow Aug 2, 2014 · Starter project for Angular apps that exports to the Angular CLI Dec 5, 2022 · Part 2 of my Angular Testing taking an in-depth look at Component Testing with Cypress. spec. Component to Test Find the component that we will test in our application. Since it is just one possible way to test Angular applications, you can compile your own testing tool chain. Replacing a dependency is called stubbing or mocking. When an @ionic/angular application is generated using the Ionic CLI, it is automatically set up for unit testing and end-to-end testing of the application. Without going into much detail about test harnesses (you can find an elaborate explanation in the Angular Material CDK documentation with lots of examples), let's look at how to Aug 15, 2022 · How to test the logic and accessibility of Angular Reactive Forms. Let's take a look at an example test suite in Playwright. The TestBed creates a dynamically-constructed Angular test module that emulates an Angular @NgModule. Nov 13, 2021 · The Complete Book On Angular Testing. Mar 13, 2019 · If you have been using Angular for any length of time, you have probably run into a parent component that references a child component using @ViewChild. May 23, 2024 · In the first version of this section, we are going to test different parameters of an angular project. Cover core Angular features: Reusable Components with state, Inputs, Outputs, templates, event handling. Aug 15, 2022 · This line adds the CounterService to the testing Module. Jasmine Core 3. By leveraging Playwright's capabilities, you can ensure your Angular app performs reliably across different browsers and environments. Sep 13, 2023 · In this article, we will delve into Angular unit testing, exploring its importance, best practices, and providing illustrative examples to help you grasp the concepts effectively. It's been three years since Testing Angular routing components with the RouterTestingModule. css('. Standalone Components come self-contained. the Angular testing utilities; The first karma test. As an example, the following is a test for a component that uses the Angular Material slider component harness: The Angular team recommends creating component test harnesses for shared components that are used in many places and have some user interactivity. Application. Angular component testing can be done manually by running the application yourself and checking to see if a component’s behavior is working as expected. Minimal component harness specifying a selector. Gone are the struggles of meticulously picking dependencies from NgModules for your Component under test. . This is the same setup that is used by the Angular CLI. Mar 17, 2023 · Writing E2E tests in Cypress for Angular components. We can resolve using the the test bed itself, usually in the beforeEach function and store the resolved dependencies for use in our test specs. Jan 28, 2023 · This setup is a trade-off with strengths and weaknesses. Take an example where the component you are testing (component A) depends on some child component (component X) and that child component depends on some other components as well (component Y). Aug 15, 2022 · As a first example, we are going to test the CounterComponent. Here’s a breakdown of how Angular’s testing utilities help test components effectively: 1. Installation To get up and running with Cypress Component Testing in Angular, install Cypress into your project: Mar 19, 2024 · The below code shows a simple example of the AAA process. The primary difference is that you don't need to declare the component in a testing module. Cypress and Playwright shine in E2E testing, offering developer-friendly APIs and reliable execution for simulating real user workflows. Angular creates an instance of the Service and injects it into the Component under test. TestBed — Angular’s powerful testing utility for creating component instances. Also known as mocking. Irrespective of the testing framework, the testing code typically consists of three phases: Arrange, Act and Assert. TestBed Aug 22, 2021 · For example, the coverage report for photo-item. Practical Examples. The test is shorter because the ServiceCounterComponent does not have Inputs or Outputs to test. Testing standalone components follows a similar approach to traditional Angular components. Here’s an example Sep 17, 2021 · Angular comes built-in with Jasmine and karma so testing is really easy. Jest is JavaScript testing framework. 9 2. For example, this could be an app developer who uses a third-party menu component and needs to interact with the menu in a unit test. cypress-example Resources. This method will be executed when the test is used to trigger and event while testing the component. Shallow vs. The default testing module is configured with basic declaratives and some Angular service substitutes that every tester needs. See the CounterComponent in action. With tools like Jest, writing tests can be efficient and straightforward. API for mounting Angular components in Cypress tests. Let's image we have the next standalone component: @ Feb 14, 2023 · In this article we want to show you the best way to test Angular material components. There are a lot of ways to develop your Angular components, and 1 day ago · What is Angular Testing Library link If you are not familiar with Angular Testing Library, here is a short introduction: (Angular) Testing Library is a set of utilities that allows you to test (Angular) components in a way that is more similar to how the components are used by the end users. Using Angular integration testing, you can test two or more units of an Angular app that work together to perform a specific task. Thankfully the same Cypress Launchpad steps also handle the configuration of your mount function . Spies and fakes Sep 30, 2016 · If you do want to use the real router, then you need to use the RouterTestingModule and letting Angular create the component, letting it inject all the required dependencies, instead of you trying to create everything were nice pieces of advice that helped me fix my test which needed to use actual angular router rather than a mocked one inside the service i was testing. component, there will be a app. For example, this could be an author of a third party Angular component library or a developer who maintains a set of common components for a large Angular application. 100+ pages with more then 30 testing examples and secrets you need to know about testing Angular apps. Some use Spectator or the Angular Testing Library instead of using TestBed directly. As stated in the above section of this tutorial on Playwright component testing, rendering the components in a virtual JS environment is sometimes not enough; it is purely JS and does not even act as a real browser. Dec 18, 2023 · Testing Angular components with data binding; Testing Angular components with RxJS; Testing Angular components with router; Testing Angular components with Angular Material; If you are interested in learning more about these topics, I recommend checking out the Cypress documentation. Testing with component harnesses Write tests with component harnesses for convenience and meaningful results. json. Sep 15, 2022 · 🎓 You can find a lot of component testing examples for different frameworks from Cypress team in the repo cypress-io/cypress-component-testing-examples. Aug 29, 2019 · Once our testing module configured we can then instantiate for example the component we want to test. Apr 19, 2017 · it does not work with angular, I have a base abstract class where almost all the logic and functionality for a real component is written then I have two components which does not have any logical code except different html and css. Unit Testing an Angular Service; Please refer to the below article to learn about Unit Jul 29, 2022 · Example tests. These dependencies make testing container Components complicated. Testing Component Mar 24, 2021 · Listing 2. Such tests require creating the component's host element in the browser DOM, as Angular does, and investigating the component class's interaction with the DOM as described by its template. This most commonly applies to widget libraries and similar reusable components. Overview; Transition and Triggers; Jan 3, 2025 · If everything is set up correctly, you should see that your test passed. As you'd want to isolate your tested component as much as possible, you can create a function that returns a fake component to import, instead of the actual nested component: function mockComponent(selector: string) { @Component({ selector, template: '' }) class MockValueAccessorComponent { // [mock implementation here] } return 5 days ago · The test is focused on the component, and the NgRx Store details are eliminated from the test. 0. For example, when testing that the Aug 18, 2024 · With a strong focus on testing Angular Components, this guide teaches you to write realistic specs that describe and verify a Component’s behavior. 0 2. For more information, see Testing. person. MIT license Code of conduct. E2E and Angular component testing examples using Cypress Topics. Cypress Component Testing supports Angular 17. The real service might ask the 📢 v13. Recreate an example manually by creating a new project locally and following a given example's instructions. Components are the building blocks of your application, and ensuring they work correctly is essential. In this . To interact with the component we're still using the Angular Testing Library because it provides Aug 15, 2022 · We have used Angular’s testing tools to set up modules, render Components, query the DOM and more. Aug 22, 2021 · This guide assumes that you know Angular basics and that you are able to build a counter Component, but struggle testing the ins and outs. Sep 28, 2023 · Here’s an example of a Cypress component tests: So I created a Cypress component test for the component, and opened it up. Why Unit Testing Matters in Angular Unit testing involves testing individual components or units of code in isolation to verify their correctness. Example of testing a standalone component: import { ComponentFixture, TestBed } from '@angular/core/testing'; Mar 21, 2025 · Angular Material also has a set of test harnesses for their components. Jan 8, 2025 · Cypress features component testing which allows the developer to use the component testing of the Angular application without being dependent on the entire application. For example, an Aug 15, 2022 · The second component (no pun intended) for getting started with Angular Component Testing in Cypress is a @cypress/angular mount function to mount your Angular component to the DOM. Feb 3, 2025 · Angular component testing means to check the quality and performance of your components. The Component under test contains a Reactive Form. The project you create with the CLI is immediately ready to test. It was created by Facebook engineers. The example below shows how to test a standalone component, but the same principles apply to Angular components that uses Modules. getValue() When you create a new Angular component, there’s just one test file created automatically. Jan 20, 2025 · Here’s a simple diagram showcasing the components of Angular testing: Fig: Basic Angular testing components. 0+. How it Works Under the Hood. Core Concepts and Terminology Basics of testing components; Component testing scenarios; Testing attribute directives; Example Angular application; Animations. Mar 26, 2019 · An angular Testing module provides testing utilities to test the app, Jasmine is a BDD testing framework and karma is a test runner. Use the cypress-component-configuration generator from the respective plugin Mar 31, 2020 · Few Examples Testing Store and other providers. For this, I focus on on-board tools supplied with Angular. You can find the repository with the example code here. Nov 2, 2020 · Angular integration testing is just as important as unit testing and end-to-end (E2E) testing. Standalone Components provide the Angular compiler with everything it needs to compile through its @Component() decorator. An integration test spans one Component together with its children and possibly connected Services as well. js 12. So, to test a component we need to create the component's host element in the browser DOM. provided via dependency injection, like Services. How to test a component in Angular application. Currently only @nx/react, @nx/angular, and @nx/next plugins support component testing. The spec for the “previous” button looks similar. In contrast, the unit test replaces the dependencies with fakes in order to isolate the code under test. These parameters are angular components, directives, services, and pipes. Dec 18, 2020 · In this blog post, let’s show you how to take advantage of all of Angular’s built-in paths for testing out an Angular service to make sure you deliver the highest-quality code consistency. How to test a standalone component in Angular and mock its `imports` This section describes how to test a standalone component. It’s time to write our first test for a component. Playwright offers a robust framework for end-to-end testing of Angular applications. Service Testing. Below you can find an example how to test almost everything what a component might have: @Input @Output @ContentChild; routing; Live example Try it on CodeSandbox; Try it on StackBlitz Apr 5, 2022 · Structure of a test. ts with couple of input properties todoContent, showDeleteButton and one output Nov 28, 2022 · We can render an Angular component with the render function from the Testing Library. Unit testing the parent component is trivial, if you just want to include the child component in the test. To do that we use a TestBed method called createComponent(). 0 3. Using component harnesses in tests: Component harness authors: Developers who maintain some reusable Angular components and want to create a test harness for its users to use in their tests. This behavior is possible to achieve with MockBuilder. Karma 5. We will test property binding and change event. Theming Angular Material with Material 2 Customize your application with Angular Material's theming system. In this section, we will cover the core concepts and terminology of Angular component testing, as well as how it works under the hood. 1. Standalone approach provides loads of benefits to our code base. Testing in Angular. When designing a Component test, the guiding questions are: What does the Component do, what needs to be tested? How do I test this behavior? We will test the following features of the CounterComponent: It displays the current count. import { async, ComponentFixture, TestBed Jan 28, 2023 · Setting up Cypress for testing your Angular project; Orchestrating a web browser to load and inspect your application; Intercepting API calls to return fixed data; We have successfully written unit and integration tests using Karma, Jasmine and Angular’s own testing tools. You can tailor Jest to fit your project's specific testing needs. Aug 15, 2022 · We simulate a click on the “next” button using the click testing helper. Jan 5, 2024 · TADA! We now can easily write Cypress Component Tests for our Components that are tied to an NgRx Store! Conclusion: Using Component Tests to write tests for your Angular Component's using NgRx Store is both super easy and creates high value tests. In our example above, Live examples; Introduction to Angular testing. The Angular Testing Status. GRAB YOUR FREE COPY Aug 14, 2023 · Testinglink. Oct 19, 2023 · Use Angular Testing Utilities: Angular offers testing utilities like TestBed, ComponentFixture, and ComponentFixtureAutoDetect to help with component testing. Jasmine is a testing (Behavior Driven Development) framework and karma. With that, an Angular component test should look like this: Nov 11, 2023 · Testing Angular components with data binding; Testing Angular components with RxJS; Testing Angular components with router; Testing Angular components with Angular Material; If you are interested in learning more about these topics, I recommend checking out the Cypress documentation. deep rendering. ts, we call ng test with the --include option. An Angular component is a TypeScript class and an HTML template working together. shallow unit tests : testing components template without rendering its May 31, 2023 · In Angular, the compileComponents method is used to compile components and their templates during the testing process. Feb 28, 2022 · A component, unlike all other parts of an Angular application, combines an HTML template and a TypeScript class. It uses the same example component as the previous tests but replaces the entities service and the modal service with the NgRx Store. Cypress lets you mount components and acts on them like a user would to ensure that they work as expected. when I run tests it does not recognise code coverage for the base class even though I have written the tests for the base class. We can resolve using the inject function at the start of each test spec. Sep 10, 2021 · In this case, you can instruct ng test to consider only the file you are currently working on. Alternatives. Code of conduct Dec 1, 2022 · Component testing in Angular. Jan 25, 2024 · Add primeng in peerDependencies section of Library package. Below code snippet below shows the component class. Neither Mar 3, 2024 · If you prefer the kind of tests that minimize mocking as much as possible, you will be pretty happy with Standalone Components. Demonstrates Angular for those with an AngularJS Dec 5, 2024 · Angular uses Jasmin and karma by default for unit testing. After a few changes, the BannerComponent presents a dynamic title by binding to the component's title property like this. In the example above, the code is fully covered except for an irrelevant else branch, marked with an “E”. Angular 10. Run with karma; Test debugging; Try the live example; Test a component. Conclusion. The destroy() method is triggered while the component is destructed. TDD and create smaller, atomic components! Basics of testing components—discover the basics of testing Angular components. Sep 17, 2024 · Let’s start by writing a simple unit test for an Angular component. It reduces architectural complexity with managing the modules and using different components within different application areas. Mar 4, 2024 · When we write a test, we check what Services our Component requires. Unfortunately, the Components' dependencies also require Services, which - some of them - we also have to provide. The ATB lets us test parts of our code as if it is being run in the context of a real Angular app. For example, the class under test is instantiated. We can use Jest with React, Angular, Vue, Node, etc. Additionally, we can pass arguments that are needed for the component to be rendered: Additionally, we can pass arguments that are needed for the component to be rendered: We can resolve dependencies in our tests using a number of methods. Feb 19, 2025 · Jasmine — The default testing framework in Angular. The testing pyramid for Angular applications Jan 23, 2025 · This makes your test lean towards being an integration test. To adequately test a component, you should test that they work together as intended. Inside the it block lies the actual testing code. Dec 21, 2024 · Example. componentInstance: Sep 7, 2023 · Methods Details; configureTestingModule: The testing shims (karma-test-shim, browser-test-shim) establish the initial test environment and a default testing module. 4. Karma — The test runner that executes your tests in a browser. This means that in most cases a Standalone Component can be mounted without ever providing any imports , decorators , or providers . 0 - Replay your tests as they occurred in your CI run and debug with confidence using Test Replay in Cypress Cloud! 🎉 Guides API Plugins Examples FAQ Learn Search ⌘K Jun 24, 2024 · Today, we’re going to explore the status of Angular testing and learn how to write our first tests. Test Components with Karma and Jasmine. you can write multiple test cases, to test angular components and structures independently of each other Beyond that, the API of any given harness is specific to its corresponding component; refer to the component's documentation to learn how to use a specific harness. Injecting the real UserService could be a nightmare. Dependencies are replaced with fakes. Node. The test comes with an example for basic functionality, ensuring the entity works. css) The tests; detectChanges: Angular change A component, unlike all other parts of an Angular application, combines an HTML template and a TypeScript class. It is also possible to write a test that integrates all parts of an Angular Module. Components. Mar 23, 2025 · The Angular Testing Library provides utility functions to interact with Angular components, in the same way as a user would. Additionally, the article mentioned useful tools like jest-auto-spies for efficient class mocking and provided resources for further exploration of testing practices in Angular. It contains the Jul 11, 2023 · AST transformers: The included AST transformers in @types/jest modify Angular component code during testing, removing CSS styles and inlining HTML templates. So you don't need to mock other May 8, 2018 · Unit tests for Angular components can be split into 2 categories: isolated tests : when we just test component functions. We can also … Feb 8, 2023 · Cover art by DALL·E 2. To test a service, you set the providers metadata property with an array of the services that you'll test or mock. Testing attribute directives—learn about how to test your attribute directives. In fact, it is usually better if they are test doubles (stubs, fakes, spies, or mocks). The component truly is the template and the class working together. On this page. Components An Angular component combines an HTML template and a TypeScript class. That's doable. Let’s dive into some practical examples of writing unit tests for Angular components and services. The Angular testing utilities include the TestBed, the ComponentFixture, For example, the root element's component instance injector. ts of the Flickr search: The report renders the source code annotated with the information how many times a line was called. A component-under-test doesn't have to be injected with real services. Testing an Angular Component. Installation. Angular Testing Library can be used with standalone components and also with Angular components that uses Modules. configureTestingModule() method takes a metadata object that can have most of the properties of an @NgModule. In the following posts, I will teach you how to test your Angular components, your next step in the testing pyramid. Aug 29, 2024 · Testing Standalone Components. Conclusion Angular component testing is an important part of Nov 30, 2017 · We went through a bunch of features and examples to try to explain how to test angular components, as you can see is quite simple and you can perform any different kind of tests. Add Component Testing to a Project. An end-to-end test is a test that simulates a user’s interaction with the application, from start to finish. Key Features: Component Testing: TestBed allows you to create instances of components and test their behavior in isolation. We’re going to test the HeroesComponent and associated Child component. Aug 7, 2020 · Find the technologies being used in our example. Demonstrates techniques for testing Angular. Feb 4, 2025 · Step 1: Create a sample react application. Angular services contain business logic, and testing them ensures that your core logic functions as expected. This is one of the main differences between Unit testing and Component testing. Its usefulness will become more apparent in future lectures, the next one being how to use the ATB to test change detection and property binding. In Listing 2, we create a minimal component harness which extends the ComponentHarness class from @angular/cdk/testing and specifies a CSS selector for a top-level DOM element of the component or it's template. Sep 3, 2024 · TestBed is essential for testing Angular components and services with minimal setup. Webpack then includes all its dependencies, like the Angular framework, but not more. When you write a unit test, you are testing a specific piece of code in isolation. You Unlike E2E testing, component testing does not create a new project. Sample code; Angular Component Testing in Depth In our component we have the following method: Copy add(n1: May 10, 2019 · When testing the DOM representation of a @Component, you're able to query its nested elements via its fixture fixture. Readme License. Toots! We're on a roooool. Testing Principles Aug 15, 2022 · They depend on the nested child Components, but also Injectables. Here's the entire test example. Finally, we verify that the Directive has rendered the next three items, the numbers 4, 5 and 6. This guide explores common component testing use cases. When you create a new component with the Angular CLI, the following files are generated by default: In the above example Jan 5, 2025 · Angular Testing Library focuses on testing user interactions and the rendered output of components, encouraging best practices by emphasizing behavior over implementation details. All examples and codes are available in the Stackblitz link for each case This small test demonstrates how Angular tests can verify a component's visual representation —something not possible with component class tests— at low cost and without resorting to much slower and more complicated end-to-end tests. The 📂 examples used can be found here. To see this in action, make a small change to app. If you don't want to be go with the on-board resources alone, you will find the same examples based on the new Cypress Component Test Runner and on Testing Library in the third-party-testing branch. Example Angular application. Unit testing is essential to ensure that your Angular applications behave as expected. Let's dive into some common scenarios for testing components. In the example application, the BannerComponent presents static title text in the HTML template. Consider the example of testing the RequestInfoComponent. In Angular, we distinguish between different types of tests; unit tests, component tests (integration tests) and end to end tests. When we create a component, service or another Angular entity, the CLI generates a test (. It has two select elements. For example, some Angular developers use Jest instead of Jasmine and Karma. While not a technique that only applies to standalone components, the way to replace a component-level provider in a component test is to use the TestBed. Feb 15, 2024 · As a result, component testing with Cypress is closer to what we do with Angular component unit tests. Usually, developers want to mock all dependencies. Feb 22, 2025 · Photo by Joel & Jasmin Førestbird on Unsplash. Testing your Angular application helps you check that your application is working as you expect. When writing unit tests for Angular components, we often interact with both the component instance and its rendered output. arrow_upward_alt Back to the top Component binding. Nov 3, 2022 · Component Testing vs Unit Testing. These tools are TestBed , ComponentFixture and DebugElement , also HttpClientTestingModule and RouterTestingModule . live example / download example. Update 1: testing Input component One of the components uses the @Input to get an object from the outer component.