A super important client needs a JavaScript function that should filter an array of objects. Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License. Be the first to know when I publish new stuff. There are many types of tests and many libraries for testing. Jest is a library for testing JavaScript code. Supporting each other to make an impact. If you’re completely unfamiliar with how Jest works in general, I recommend you start with this introduction. Data-driven Unit Tests are a very efficient and easy way to run a test with a series of input data. As you can see it takes two arguments: a string for describing the test suite, and a callback function for wrapping the actual test. Create a new folder inside your project root called src and create a file named filterByTerm.js where we'll place and export our function: Now let's pretend I'm a fresh hired colleague of yours. Jest has built-in code coverage, you can activate it in two ways: Before running the test with coverage make sure to import filterByTerm in __tests__/filterByTerm.spec.js: Save the file and run the test with coverage: A nice summary of the testing coverage for our function. Remember, testing is a matter of inputs, functions, and expected outputs. I hope this tutorial was useful to you in seeing how to get started with testing Vue.js with Jest! In this tutorial I’m going to show you how to test Vue components. # Writing a unit test. Once you understand the basics of Jest, you’re ready to jump right in and see how it can be used to test your Vue apps. The directory where Jest should output its coverage files. You can find the code for this tutorial on Github: getting-started-with-jest alongside with the solution for the exercises. Here's how a typical test flow looks like: Really, that's it. For both cases you can help yourself by thinking of tests as of bits of code that check if a given function produces the expected result. We can expect for example an array with a single object, given "link" as the search term: Now we're ready to write the actual test. You get paid; we donate to tech nonprofits. All you gotta do now is mock a request and write your test. Inside __tests__, create a file called app.spec.js. This is a terse output. We can write tests like this: These tests all pass! In Jest, Node.js modules are automatically mocked in your tests when you place the mock files in a __mocks__ folder that's next to the node_modules folder. This is how jest is able to find all the test files to be executed. Test your app! It is a convention borrowed from Ruby for marking the file as a specification for a given functionality. Here's a minimal implementation of filterByTerm: Here's how it works: for each element of the input array we check the "url" property, matching it against a regular expression with the match method. We’re now ready to write some tests. Testing won't be scary anymore if you think in these terms: input - expected output - assert the result. Jest is a JavaScript testing framework maintained by Facebook, Inc. designed and built by Christoph Nakazawa with a focus on simplicity and support for large web applications. When we are mocking our component however, we must call $nextTick() on wrapper.vm, which is the component underlying the wrapper. Open up package.json and configure a script named test for running Jest: As developers, we all like creativity freedom. setData allows you to set the component’s data. For example, in VSCode doing Ctrl+Shift+P > TypeScript: Restart TS server helps, as sometimes it fails to recognize jest, or the test file to be a module, etc. But guess, the variable that is connected to the input element via v-model, is not. yarn add --dev jest babel-jest babel-preset-es2015 babel-preset-react enzyme enzyme-to-json isomorphic-fetch moment nock prop-types react react-addons-test. Time to create your first Jest test. To learn more about UI testing I highly suggest taking a look at JavaScript End to End Testing with Cypress. One-page guide to Jest: usage, examples, and more. As an exercise for you write two new tests and check the following conditions: In the next section we'll see another important topic in testing: code coverage. That's a good thing actually. Creating A Test File. If you're ready to take the leap and learn about automated testing and continuous integration then Automated Testing and Continuous Integration in JavaScript is for you. Hence we expect the message to be TRY AGAIN. Educator and consultant, I help people learning to code with on-site and remote workshops. On the other hand, when we set the sum to be correct, wrapper.vm.message will say ‘SUCCESS!’. Since those variables were initialized in data, they are reactive. This post goes how to skip and exclude a single test, a whole Jest test suite and a whole Jest test file using the CLI or Jest built-ins. This is a pretty basic test which checks if the data for our component is a function. Jest will by default look for test files inside of __tests__ folder. PS: I'm assuming Jest because it's become the industry standard for JavaScript testing in the past few years. Delete the src/components directory and modify App.vue as such: Take a look through the code and see if you can figure out what the app does. That tool is code coverage, and it's a powerful utensil in our toolbox. Here we are testing add function which takes two numbers and returns the sum of those numbers. Jest works smoothly for testing React apps (both Jest and React are from Facebook's engineers). Let’s write some tests for the app’s more Vue-specific functionality. The purpose of this tutorial is to introduce you to Test Data, its importance and give practical tips and tricks to generate test data quickly. Let’s understand the above code. Inside this folder you'll find a bunch of files, with /coverage/index.html as a complete HTML summary of the coverage for your code: If you click on the function name you'll also see the exact untested line of code: Neat isn't? Component.test.js or Component.spec.js). Tagged with jest, tdd, unittests, testautomation. Then go ahead and run $ npm run serve from the root directory of your project. Try making a few guesses! Configuration Precedence. Jest is one of the most popular test runner these days, and the default choice for React projects. :: All rights reserved 2020, Valentino Gagliardi - Privacy policy - Cookie policy :: "it should filter by a search term (link)", "node --experimental-vm-modules node_modules/jest/bin/jest.js", Testing React Components: The Mostly Definitive Guide, JavaScript End to End Testing with Cypress, Automated Testing and Continuous Integration in JavaScript, 4 ways to fake an API in frontend development, Cypress Tutorial for Beginners: Getting started with End to End Testing. It works with projects using Babel , TypeScript , Node.js , React , Angular , Vue.js and Svelte . Then, create a file jest.config.js with the following content: Go ahead and open up the alligator-test directory in your code editor of choice. Write for DigitalOcean I know nothing about testing and instead of asking for more context I go straight inside that function for adding a new if statement: Unless I tell you "there's a new statement to test" you're not going to know exactly what to test in our function. We'd like to help. If you put a JavaScript file in one of these folders, Jest will try to run it when you call Jest, for better or for worse. Good luck out there. Next up we're going to meet another function called test which is the actual test block: At this point we're ready to write the test. Examples. We can use it to validate whether certain values are present using Jest’s expect function. I’m Valentino! Not yet. As a tester, you may think that ‘Designing Test cases is challenging enough, then why bother about something as trivial as Test Data’. By default it looks for .js, .jsx, .ts and .tsx files inside of __tests__ folders, as well as any files with a suffix of .test or .spec (e.g. But, when it comes to serious stuff most of the time you don't have so much privilege. If you don't want to mess up your default Node.js version you can use a tool like nvm to install multiple Node.js versions. Line 3 and 4 have new imports: getRecord and registerLdsTestWireAdapter. So, when the button for submission is clicked, the correct sum has not been entered. While this tutorial has content that we believe is of great benefit to our community, we have not yet tested or If you don’t have the Vue CLI installed on your machine already, start by running either: Now you will be able to run the vue command from the command line. Being a test-savvy JavaScript developer you want to follow test-driven development, a discipline which imposes to write a failing test before starting to code. If using the usePathForSuiteName and suiteNameTemplate, the usePathForSuiteName value will take precedence. Every time you start writing a new suite of tests for a functionality wrap it in a describe block. There are many types of testing and soon you'll be overwhelmed by the terminology, but long story short tests fall into three main categories: In this Jest tutorial we'll cover only unit testing, but at the end of the article you'll find resources for the other types of tests. See the micromatch package for details of the patterns you can specify. coveragePathIgnorePatterns [array] # Default: ["/node_modules/"] An array of regexp pattern strings that are matched against all file paths before executing the test. If you're writing a web application a good starting point would be testing every page of the app and every user interaction. Try to reach 100% code coverage by testing the new statement I've added. It takes two parameters. x1 and x2 are set from our previous test. For convenience, we're going to create the function in the same file where the test lives. Here's the complete test: At this point you can give it a shot with: "ReferenceError: filterByTerm is not defined". Let's fix it in the next section! To run an individual test, we can use the npx jest testname command. Then, if we need to update our tests, we update each copy of the test. Just wanted to say that it may not work right away. This is an sample output running tests with Jest. One of Jest’s best features is its watch mode, which watches for file changes and runs tests accordingly. Doing it this way, you would have one open terminal tab for your Jest tests in watch mode with npm run test:watch and one open terminal tab to start your React application with npm start.Every time you change a source file, your tests … Let’s create a Vue app called alligator-test. Have we finished testing? It's an open source project maintained by Facebook, and it's especially well suited for React code testing, although not limited to that: it can test any JavaScript code. Save the file and run the tests. A quick overview to Jest, a test framework for Node.js. All without Webpack. Functional cookies enhance functions, performance, and services on the website. Start by creating a file called globalMocks. Maybe we do that several times. For making the test pass we'll use a native JavaScript function called filter which is able to filter out elements from an array. getRecord is coming from the LDS API. From this point, if you’re interested in diving deeper into what Jest can do, I’d recommend reading up on Snapshot testing. For example, if you a file called __mock__/fs.js, then every time the fs module is called in your test, Jest will automatically use the mocks. Here's the test: To break things down even further here's how you would call the function in your code: In a Jest test you should wrap the function call inside expect which coupled with a matcher (a Jest function for checking the output) makes the actual tests. Now you can run your Jest tests in watch mode. As you can see line 3 is uncovered. What is code coverage? Sign up for Infrastructure as a Newsletter. Running jest by default will find and run files located in a __tests__ folder or ending with .spec.js or .test.js.. In tech jargon testing means checking that our code meets some expectations. First let's define a simple input, an array of objects: Next up we're going to define the expected result. whether they fail or pass depends only on your code, and not on the data that the API returns.It’s easier in the long run: no need to first login or set some state before you can start testing a certain endpoint.Setting up Jest In this tutorial we've got a rather simple spec from our project manager. Hub for Good It can even figure out which subset of tests to run based on the file that changed. Here's the complete code: Great job! If we create a new app by using create-react-appjest is already included in our react project. Jest ships as an NPM package, you can install it in any JavaScript project. Contribute to Open Source. Looking for JavaScript and Python training? This guide targets Jest v20. Jest provides functions to structure your tests: describe: used for grouping your tests and describing the behavior of your function/module/class. change your current working directory by running following command. For example, if you want to place your test files in a folder named test_folders, you would write your Jest configuration as … Some examples include: cookies used to analyze site traffic, cookies used for market research, and cookies used to display advertising that is not directed to a particular individual. In a real project you would define the function in another file and import it from the test file. edited it to ensure you have an error-free learning experience. Run $ npm test in your Terminal – the test should pass! Now we've got the project set up, it's time to write a unit test. Before we do that, let's look at the test code to see what’s happening. Hi! Click through for source. First, we need to create a new react app by using create-react-appcommand line tool. Hacktoberfest Before talking about it let's make a quick adjustment to our code. The most common question is "How do I know what to test?". Suppose you want to test a module at src/SimpleModule.js: In a test file at __tests__/SimpleModule.spec.js you can import the module as you would do normally: Note that things could change a bit in the future, keep an eye on this issue. In other words it should return the matching objects even if the search term is an uppercase string: For testing this condition we introduced a new test: For making it pass we can tweak the regular expression provided to match: Rather than passing searchTerm straight away we can construct a case-insensitive regular expression, that is, an expression that matches regardless of the string's case. jest How to mock event. Open up filterByTerm.spec.js and create a test block: Our first friend is describe, a Jest method for containing one or more related tests. create a new folder called __tests__ in your src folder because by default jest … This time we are mounting the component, which gives us back a wrapper. Finally, we’re going to test whether our app gives the correct output according to what we intend it to do – test addition! Let’s add another describe block to our test file. It's on our list, and we're working on it! If you want to learn how to test React components check out Testing React Components: The Mostly Definitive Guide. As with every JavaScript project you'll need an NPM environment (make sure to have Node installed on your system). The way we wrote it back in the coding phase of this tutorial, we indeed defined it as a function. At the top of app.spec.js we’re going to import the following from @vue/test-utils as well as our App component itself: Run $ npm test in your Terminal – the test should pass! The guide covers unit testing components, class components, functional components with hooks, and the new Act API. Putting your test code next to the files they are testing. React is a super popular JavaScript library for creating dynamic user interfaces. Now you head over to localhost:8080 in your browser and see the working app. Create the new folder: Next up create a new file called filterByTerm.spec.js inside __tests__. When you run $ npm test the test should pass. Run the below command to install react app. Now you can run your Jest tests in watch mode. Let’s get in touch! filterByTerm should account also for uppercase search terms. The test fails due to the missing mock data file that we create next. Jest is a JavaScript test runner, that is, a JavaScript library for creating, running, and structuring tests. By default jest will catch any test files (searching recursively through folders) in your project that are named *.spec.js or *.test.js. Good job! Let’s add another describe block to our test file. The glob patterns Jest uses to detect test files. Let's stress the function with an upper-case search term: Run the test ... and it will fail. Time to fix it again! Choose the default preset at the prompt (hit the enter key). It works! Jest is also the default test runner in create-react-app. It’s faster: you don’t have to wait until the API response comes in and you don’t have to deal with rate limits.It makes your tests ‘pure’, i.e. jest-each is a small library that lets you write jest test cases with just one line.. It was added to Jest in version 23.0.1 and makes editing, adding and reading tests much easier.This article will show you how a jest-each test is written with examples of where we use it on our projects.. A simple example jest test for a currencyFormatter function looks like this: When debugging or writing units tests with Jest it can be useful to specify a single file or test to run or to exclude a specific failing test for the Jest run. Writing tests. For more information, we can use the --verbose option. Each of those tests is saying "When you fetch() this URL, return this object. Create a folder __tests__ and in this folder a file github.test.js with the following code: For example: a function called "transformer" should returns the expected output given some input. The first rule is that any files found in any directory with the name __test__ are considered a test. You may wonder why the extension includes .spec.. You get paid, we donate to tech non-profits. We’re going to write unit tests and snapshot tests with Jest and Vue Test Utils. We'll use expect, and a Jest matcher for checking if our fictitious (for now) function returns the expected result when called. Working on improving health and education, reducing inequality, and spurring economic growth? Just beware that Jest would create a __snapshots__ directory next to test files that performs snapshot testing. Then, we can find that our reactive properties are updated. If you wish to specify your own location, you can pass the testRegex option to the Jest configuration object in your package.json. It's almost impossible to imagine all the paths our code can take and so arises the need for a tool that helps to uncover these blind spots. In this article, I'll give you a short walkthrough with examples in Jest. To learn more about Jest matchers check out the documentation. wrapper.find returns a wrapper for the button element (though there are 2 buttons on our page, the one that we want is the first button on the page so it gets grabbed). I did a rm -rf node_modules && npm cache clean --force && npm install ^ began erroring. How to test JavaScript code with Jest? Jest recommends creating a __tests__ directory right next to the code being tested, but feel free to structure your tests as you see fit. What it takes to make our function fail? Jest is a popular JavaScript testing framework that comes packed with a lot of goodies for developers. If you want to keep code coverage always active configure Jest in package.json like so: You can also pass the flag to the test script: If you're a visual person there's also a way to have an HTML report for code coverage, it's simply as configuring Jest like so: Now every time you run npm test you can access a new folder called coverage in your project folder. Reproduced on mac here. This MATLAB function adds a file to the Inputs section of the test case and returns a test input object, sltest.testmanager.TestInput. I’ve seen two popular ways suggested for organizing tests in Jest: Putting all of your test code into a neatly organized /tests directory. It will also find files called test.js or spec.js. This above command will download the react related files in ‘react-tesing’ folder. Testing is a big and fascinating topic. Jest ships as an NPM package, you can install it in any JavaScript project. It allows you to write tests with an approachable, familiar and … By default, Jest expects to find test files in a folder called __tests__ in your project folder. For me it occurred after manually incremented all the @vue/* packages to rc.3 from one of the betas (beta.16 I think). What's really missing is the implementation of filterByTerm. Jest is very fast and easy to use The good news is, starting with version 23 of Jest, there is built-in support for creating data-driven tests. You should see a simple list with my profile data. There are two scenarios most of the times: What to do? Below are some example configuration values and the rendered … Let’s first try to unit test the function getUser. With code coverage you can discover what to test when in doubt. Jest is one of the most popular test runner these days, and the default choice for React projects. Here's the fix: Run it again and see it passing. Doing it this way, you would have one open terminal tab for your Jest tests in watch mode with npm run test:watch and one open terminal tab to start your Node application with npm start.Every time you change a source file, your tests … Learn the basics of testing JavaScript with this Jest tutorial for beginners! ie: if usePathForSuiteName=true and suiteNameTemplate="{filename}", the filepath will be used as the name attribute of the in the rendered jest-junit.xml).. Once nvm is in place you can install the latest release of Node.js with: To make import work in Jest, package.json should have the key type configured as module, (see Node.js doc for more) and Jest must be called through Node.js with a flag: Once done you can start using import in Jest. You can help us out by using the "report an issue" button at the bottom of the tutorial. . Now open your ‘react-testing’ folder in your favorite code editor. This is a pretty basic test which checks if the data for our component is a function. For every object we must check a property called "url" and if the value of the property matches a given term then we should include the matching object in the resulting array. We've got to follow specifications, that is, a written or verbal description of what to build. jest-results.json - raw jest json data /js - javascript render files /css - css stylings; ... to your current location in a folder “data” and “simplePassingTests.json” contains saved JSON output from a jest test invocation, you can run the CLI providing a single positional input jest JSON file: I am currently testing one of my React. How does Jest know what’s a test file and what isn’t? After that, run the following command to add our testing dependencies (@vue/cli-plugin-unit-jest and @vue/test-utils): Next, modify your project’s package.json file to have an entry in scripts which says "test": "jest". The way we wrote it back in the coding phase of this tutorial, we indeed defined it as a function. Modules that are mocked with jest. Jest is a JavaScript test runner, that is, a JavaScript library for creating, running, and structuring tests. As per spec the function under test should leave out the objects whose url property does not match the given search term. In this Jest tutorial you learned how to configure Jest for coverage reporting, how to organize and write a simple unit test, and how to test JavaScript code. Let’s make some changes to the default files that the vue-cli create for us. What means testing? Get the latest tutorials on SysAdmin and open source topics. Hopefully you can pass the test before we get to writing our tests. At the time of writing if you wish to use import ES module syntax in your Jest tests without babel and friends you should have Node.js >=v13.x, and Jest >=26.1.0 installed. , Node.js, React, Angular, Vue.js and Svelte pretty basic test which checks if the data our... Go ahead and run $ npm run serve from the root directory of your project folder write! Create-React-Appjest is already included in our React project correctness of any JavaScript project your tests and describing the of... Testregex option to the missing mock data file that changed data, are..., functional components with hooks, and expected outputs test Utils test we... That changed be try AGAIN default look for test files this time we are add... Value will take precedence install ^ began erroring tests like this: these tests all pass this is JavaScript! Not work right away project set up, it 's become the industry standard for JavaScript testing framework to! Your group ta do now is mock a request and write your test code next the! Above command will download the React related files in ‘ react-tesing ’ folder I help jest test data file... That need to be correct, wrapper.vm.message will say ‘ SUCCESS!.... Alongside with the solution for the app and every user interaction TypeScript, Node.js, React, Angular Vue.js! Checks if the data for our component is a super important client needs a JavaScript testing in the same where. Function in another file and what isn ’ t suiteNameTemplate, the variable that is, a written verbal. Any directory with the solution for the app ’ s a test framework for Node.js Vue called. It may not work right away, when it comes to serious stuff most of the most common is. Leave out the objects whose URL property does not match the given search term: run it AGAIN and the... Testing React components check out testing React apps ( both jest and React from. Wish to specify your own location, you can help us out using... As a function just wanted to say that it may not work right.... Node_Modules & & npm install ^ began erroring for JavaScript testing in the root directory of your.. Testing JavaScript with this introduction that changed system ) you want to learn how to get started with testing with. For this tutorial on Github: getting-started-with-jest alongside with the solution for the app and every interaction. Up your default Node.js version you can install it in any JavaScript project, running, and tests... Applications are also made of units of code could jest test data file beginners works with using... Tutorial we 've got to follow specifications, that is connected to jest. Remote workshops in this tutorial, we can use it to validate whether certain values are present using ’! Tech non-profits n't be scary anymore if you do n't want to mess up your default Node.js you... Directory by running following command re going to create the new Act API open up and... Just wanted to say that it may not work right away units of code like functions and modules need... Prompt ( hit the enter key ) be testing every page of the most popular runner! Past few years look at JavaScript End to End testing with Cypress it. Your own location, you can pass the testRegex option to the files they are testing wrapper.vm.message... Default Node.js version you can find the code for this tutorial, we donate tech... Need an npm environment ( make sure to have Node installed on system..., which is able to filter out elements from an array of objects: next up we 're working improving! A wrapper found in any JavaScript project you would define the function in the root directory of your project package.json... Write tests like this: these tests all pass any directory with the for... Lets you write jest test cases with just one line would create folder! Or spec.js but, web applications are also made of units of code could paralyze.. Angular, Vue.js and Svelte your tests: describe: used for your. The coding phase of this tutorial, we indeed defined it as a function s expect function libraries. The same file where the test... and it 's on our list, and the new Act API via... Returns the expected result sum has not been entered 've got a rather simple spec from our manager! Typescript, Node.js, React, Angular, Vue.js and Svelte code coverage and. Now we 've got a rather simple spec from our previous test specifications, is! The testRegex option to the input element via v-model, is not will. Current working directory by running following command favorite code editor system ) key ) test case and returns test. Developers, we indeed defined it as a function a short walkthrough examples! Command will download the React related files in a describe block to our test file in! Usepathforsuitename and suiteNameTemplate, the variable that is, a test framework for Node.js you get paid we! Found in any directory with the solution for the exercises new React app by using create-react-appcommand tool! Npx jest testname command - expected output given some input inequality, and 's. And easy way to run a test framework for Node.js test? `` the way wrote! To serious stuff most of the times: what to build get to writing our tests next. -- verbose option multiple Node.js versions just beware that jest would create a new app by using create-react-appcommand line.. Elements from an array of objects with hooks, and structuring tests can! On SysAdmin and open source topics preset at the test fails due to the jest configuration object in your code! Jest ’ s expect function to find test files that performs snapshot testing function getUser expect the message be. Unit test the test... and it will also find files called test.js or.... Projects using Babel, TypeScript, Node.js, React, Angular, Vue.js and Svelte your function/module/class open topics..., a written or verbal description of what to build of code could paralyze.! Values are present using jest ’ s add another describe block good starting point would be testing every of... Latest tutorials on SysAdmin and open source topics called filter which is able find. Message to be tested too for a given functionality sum has not been entered JavaScript. Convention borrowed from Ruby for marking the file as a specification for functionality!: Really, that is, a JavaScript function called filter which is standard jest convention package you. The function in the coding phase of this tutorial we 've got to follow specifications, that,! Rather simple spec from our project manager s happening via v-model, is not applications are also of. A native JavaScript function called `` transformer '' should returns the sum of those tests saying. People learning to code with on-site and remote workshops be testing every page of the tutorial information. Typescript, Node.js, React, Angular, Vue.js and Svelte tests to a! To create the new folder: next up we 're working on improving health and,... Performs snapshot testing should pass ’ m going to define the function another. Now is mock a request and write jest test data file test fetch ( ) this,! Write your test code next to test files to be correct, wrapper.vm.message will say ‘ SUCCESS! ’ components! And modules that need to update our tests, we indeed defined it as a.! We 've got to follow specifications, that is, starting with version 23 of jest, JavaScript! Takes two numbers and returns the expected output given some input sum of those.! A functionality wrap it in a __tests__ folder % code coverage you can find the code for this tutorial 've... Find that our code meets some expectations general, I 'll give you short. Health and education, reducing inequality, and spurring economic growth running following command which! A request and write your test what to test Vue components for Node.js easy way to based... The Inputs section of the tutorial assuming jest because it 's a powerful utensil our. Mostly Definitive Guide and modules that need jest test data file be executed for example: a function reach... React project expected outputs it passing assert the result a native JavaScript function that should filter an of. Efficient and easy to use first, we indeed defined it as a specification for a functionality wrap in... Tests and snapshot tests with jest 4 have new imports: getRecord and registerLdsTestWireAdapter components, functional components hooks! As a function writing our tests, we can use the -- verbose option time to some! Cases with just one line it to validate whether certain values are present using jest ’ s function... Discover what to test? `` test file 's stress the function under test should pass testRegex to... Testregex option to the input element via v-model, is not the button submission! Jest configuration object in your favorite code editor a function suggest taking a look at JavaScript to! Your own location, you can pass the testRegex option to the files they testing. Guess, the usePathForSuiteName value will take precedence easy way to run an individual test, we 're going create! A folder called __tests__ in the coding phase of this tutorial is for users familiar with unit testing,! Able to filter out elements from an array of objects find all the lives... -- verbose option s create a new file called filterByTerm.spec.js inside __tests__ package for details of app. Choose the default choice for React projects we ’ re completely unfamiliar with how jest in... Unit testing components, functional components with hooks, and spurring economic growth variable that is a...