投稿時間:2022-04-23 20:17:27 RSSフィード2022-04-23 20:00 分まとめ(19件)

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python	Pythonタグが付けられた新着投稿 - Qiita	プログラミング超超初心者がまずはpythonを触る	https://qiita.com/Reyow/items/0c2354b307cf22716797	一念発起	2022-04-23 19:15:21
python	Pythonタグが付けられた新着投稿 - Qiita	petastormやーる	https://qiita.com/SatoshiGachiFujimoto/items/c122e348387bf3896304	Detail Nothing	2022-04-23 19:11:31
js	JavaScriptタグが付けられた新着投稿 - Qiita	2つのTransformStreamを合成する	https://qiita.com/access3151fq/items/90ee323b404ee25d5512	nodejs	2022-04-23 19:49:13
Azure	Azureタグが付けられた新着投稿 - Qiita	petastormやーる	https://qiita.com/SatoshiGachiFujimoto/items/c122e348387bf3896304	Detail Nothing	2022-04-23 19:11:31
海外TECH	MakeUseOf	How to Compress a Video and Reduce the File Size	https://www.makeuseof.com/compress-video-file/	video	2022-04-23 10:45:14
海外TECH	MakeUseOf	9 Creative YouTube Cooking Channels to Get Your Kids in the Kitchen	https://www.makeuseof.com/youtube-cooking-channels-to-get-kids-interested/	kitchenwant	2022-04-23 10:30:13
海外TECH	MakeUseOf	Is It Worth Buying a OLED TV? 9 Pros and Cons to Consider	https://www.makeuseof.com/buy-oled-tv-pros-and-cons/	consideroled	2022-04-23 10:15:13
海外TECH	DEV Community	Jest Testing	https://dev.to/mokadevlight/jest-testing-2ckd	Jest TestingWhen it comes to unit testing frameworks for JavaScript Jest is certainly a serious contender for the spot Initially Jest was created by Facebook specifically for testing React applications It s one of the most popular ways of testing React components Since its introduction the tool has gained a lot of popularity This popularity has led to the use of Jest for testing both JavaScript front end and back end applications In this article we ll talk about the ins and outs of Jest to help you get started with testing Before we get there though we ll offer you a refresher on unit testing and its importance for software quality After that we ll start covering Jest specifically explaining its definitionwhat are its main advantagesand some of its most important characteristicsWe ll walk you through a hands on tutorial on how to get started with Jest You ll learn more about the vocabulary associated with Jest testing like mocks and spies Also we ll cover some of the basics of Jest testing like using describe blocks and the keywords it and expect Finally we ll take a look at snapshot testing and why it s particularly useful for front end testing Let s get started The What and Why of Unit TestingThe topic of software testing can often feel overwhelming There are just too many types of testing each operating on a different layer verifying distinct aspects of the application and offering its unique type of feedback Among the myriad types of automated testing unit testing is often cited as the most important oneーsee test automation pyramid Unit tests verify the smallest parts of your application in complete isolation ensuring they work as expected In unit testing you aren t allowed to interact with external dependenciesーe g make an HTTP callーnor generate any kind of side effect As a result of those properties unit tests are usually very fast to executerelatively easy to setup not requiring any elaborate configurationvery precise in the feedback they provideIn the scale of automated tests unit tests sit at the extreme opposite of end to end testing The latter provide less precise feedback are generally slower more fragile though more realistic The former are super precise in their feedback are fast and typically only fail due to the errors in the code However they are in less realistic because in real life users don t interact with units in complete isolation To sum it up unit tests are far from being the only type of tests your application needs but they should represent a significant portion of your testing strategy What Is Jest Jest is a popular test framework for JavaScript It claims to provide “delightful JavaScript testing and after our tutorial I bet you might agree with this claim Jest prides itself in offering a complete and hassle free experience The completeness comes from the fact that Jest doesn t rely on third party tools for much of its functionality like some competitors do And the hassle free part is due to Jest s zero configuration setup You can install it and start writing your first test in no time As mentioned in the introduction Jest has gained a lot of popularity over recent years for both front end and back end testing Many large companiesーincluding Twitter Instagram Pinterest and Airbnbーuse Jest for React testing Jest itself is actually not a library but a framework There s even a CLI tool that you can use from the command line To give an example the CLI tool allows you to run only specific tests that match a pattern Besides that it hosts much more functionality which you can find in the CLI documentation In summary this means that Jest offers a test runner assertion library CLI tool and great support for different mocking techniques All of this makes it a framework and not just a library Let s take a quick look at the advantages of Jest Advantages of JestHere s a shortlist of Jest advantages Offers a CLI tool to control your tests easilyComes with an interactive mode that automatically runs all affected tests for the code changes you ve made in your last commitProvides syntax to test a single test or skip tests with only and skip This feature is useful when debugging individual testsProvides excellent documentation with plenty of examples and a supportive community You can join the Jest community via Discord or ask questions on Stack OverflowBrings easy mocking to developers as it s one of the most painful things to do for testing engineers We explain further in this post how Jest mocking worksJest offers code coverage out of the box through its CLIーjust use the coverage option or the collectCoverage property in the Jest configuration file Jest CharacteristicsFrom Jest s website we can find four main characteristics of Jest Zero config “Jest aims to work out of the box config free on most JavaScript projects This means you can simply install Jest as a dependency for your project and with no or minimal adjustments you can start writing your first test Isolated Isolation is a very important property when running tests It ensures that different tests don t influence each other s results For Jest tests are executed in parallel each running in their own process This means they can t interfere with other tests and Jest acts as the orchestrator that collects the results from all the test processes Snapshots Snapshots are a key feature for front end testing because they allow you to verify the integrity of large objects This means you don t have to write large tests full of assertions to check if every property is present on an object and has the right type You can simply create a snapshot and Jest will do the magic Later we ll discuss in detail how snapshot testing works Rich API Jest is known for having a rich API offering a lot of specific assertion types for very specific needs Besides that its great documentation should help you get started quickly Before we dive a bit further into the Jest vocabulary let s show you how you can get started with this tool in practice Get Started With Jest A Practical Hands On Tutorial in StepsWe ll now walk you through our five step tutorial on how to get started with testing using Jest Install Jest GloballyThe first step will be to install Jest globally That way you gain access to Jest s CLI Make sure you have Node js installed because you ll use npm Go to your terminal and run the following command npm install g jestOnce the installation is complete execute jest version to see the version installed Create a Sample ProjectYou ll now create a npm based project to house our production code and test code Start by creating a folder and accessing it mkdir learning jestcd learning jestThen run npm init y to create a project As a result you should have a package json file inside your folder with this content name learning jest version description main index js scripts test echo Error no test specified amp amp exit keywords author license ISC Now create a file called index js and paste the following content on it function fizz buzz numbers let result for number of numbers if number result push fizzbuzz else if number result push fizz else if number result push buzz else result push number return result join module exports fizz buzz The code above contains a function that solves the famous FizzBuzz programming interview question Add Jest to the ProjectYou ll now add Jest as a dev dependency to the project Run the following command npm install save dev jestThen go to your package json file and change this part scripts test echo Error no test specified amp amp exit To this scripts test jest Write Your First TestNow create a new file called index test js Paste the following content on it const fizz buzz require index describe FizzBuzz gt test should result in fizz gt expect fizz buzz toBe fizz test should result in buzz gt expect fizz buzz toBe buzz test should result in fizzbuzz gt expect fizz buzz toBe fizzbuzz test should result in fizz gt expect fizz buzz toBe fizz We ll explain Jest s syntax in more detail later For now understand we re verifying that passing an array containing should result in “fizz an array containing should result in “buzz an array containing should result in “fizzbuzz passing an array with and should result in “ fizz Run Your First TestYou re now ready to run your first test Back to your terminal simply run npm test You should see a result like the following As you can see all four tests passed All test suites were executedーwhich makes sense since we only have one The total time for execution was seconds Now that you had a test of Jest let s take a step back and understand in more detail its syntax and vocabulary Jest VocabularyLet s take a look at two of the most commonly used Jest terms that are also used in other testing tools mock and spy Jest Vocabulary MockFrom the Jest documentation we can find the following description for a Jest mock “Mock functions make it easy to test the links between code by erasing the actual implementation of a function capturing calls to the function and the parameters passed in those calls In addition we can use a mock to return whatever we want it to return This is very useful to test all the paths in our logic because we can control if a function returns a correct value wrong value or even throws an error In short a mock can be created by assigning the following snippet of code to a function or dependency jest fn Here s an example of a simple mock where we just check whether a mock has been called We mock mockFn and call it Thereafter we check if the mock has been called const mockFn jest fn mockFn expect mockFn toHaveBeenCalled The following example also mocks a return value for checking specific business logic We mock the returnsTrue function and let it return false const returnsTrue jest fn gt false console log returnsTrue false Next up let s explore what a spy is Jest Vocabulary SpyA spy has a slightly different behavior but is still comparable with a mock Again from the official docs we read “Creates a mock function similar to jest fn but also tracks calls to object methodName Returns a Jest mock function What this means is that the function acts as it normally wouldーhowever all calls are being tracked This allows you to verify if a function has been called the right number of times and held the right input parameters Below you ll find an example where we want to check if the play method of a video returns the correct result but also gets called with the right parameters We spy on the play method of the video object Next we call the play method and check if the spy has been called and if the returned result is correct Pretty straightforward In the end we must call the mockRestore method to reset a mock to its original implementation const video require video test plays video gt const spy jest spyOn video play const isPlaying video play expect spy toHaveBeenCalled expect isPlaying toBe true spy mockRestore OK now that we know about the two most used technical terms let s explore the basic structure Jest BasicsLet s take a look at some basics on writing tests with Jest Jest Basics Describe BlocksA describe block is used for organizing test cases in logical groups of tests For example we want to group all the tests for a specific class We can further nest new describe blocks in an existing describe block To continue with the example you can add a describe block that encapsulates all the tests for a specific function of this class Jest Basics “It or “Test TestsFurthermore we use the test keyword to start a new test case definition The it keyword is an alias for the test keyword Personally I like to use it which allows for more natural language flow of writing tests To give an example describe Beverage gt it should be delicious gt expect myBeverage delicious toBeTruthy Jest Basics MatchersNext let s look at the matchers Jest exposes A matcher is used for creating assertions in combination with the expect keyword We want to compare the output of our test with a value we expect the function to return Again let s look at a simple example where we want to check if an instance of a class is the correct class we expect We place the test value in the expect keyword and call the exposed matcher function toBeInstanceOf to compare the values The test results in the following code it should be instance of Car gt expect newTruck toBeInstanceOf Car The complete list of exposed matchers can be found in the Jest API reference Jest Basics Setup and TeardownIt s important we understand how to prepare and clean up a test For example a particular test relies on a mocked database We don t want to call a function to set up and clean up the mocked database for each test To solve this problem we can use the beforeEach and afterEach functions to avoid code duplication Both functions allow you to execute logic before or after each test Here s an example of mocking a database before each test and tear it down when each test has finished describe tests with database gt beforeEach gt initDB afterEach gt removeDB test if country exists in database gt expect isValidCountry Belgium toBe true Moreover you can also make use of beforeAll and afterAll functions Both functions will run before or after all tests but only once You can use these functions to create a new database connection object and destroy it when you ve completed the tests beforeAll gt return createDBConnection afterAll gt return destroyDBConnection Lastly let s take a look at snapshot testing Jest Basics Snapshot Testing for React Front EndsAt last the Jest documentation suggests using snapshot tests to detect UI changes As I mentioned earlier snapshot testing can also be applied for checking larger objects or even the JSON response for API endpoints Let s take a look at an example for React where we simply want to create a snapshot for a link object The snapshot itself will be stored with the tests and should be committed alongside code changes it renders correctly gt const tree renderer create lt Link page gt Facebook lt Link gt toJSON expect tree toMatchSnapshot Following the above code renders the following snapshot exports renders correctly lt a className normal href onMouseEnter Function onMouseLeave Function gt Facebook lt a gt If the link object changes this test will fail in the future If the changes to the UI elements are correct you should update the snapshots by storing the results in the snapshot file You can automatically update snapshots using the Jest CLI tool by adding a “ u flag when executing the tests Getting Started With Jest TestingFinally we ve covered all the basic elements for you to get started with Jest testing When you re writing your first test cases it can feel a bit uncomfortable writing mocks However mocks are especially useful in unit testing because they allow you to test the business logic of your function without worrying about its dependencies	2022-04-23 10:49:02
海外TECH	DEV Community	Describe CSS Background Properties	https://dev.to/mrezaulkarim/describe-css-background-properties-4f62	Describe CSS Background Properties CSS Background PropertiesWe regularly see that the back of a website is the different color Some websites also have images on the back Somewhere again there is more than one image Some of these are set with CSS Background Properties CSS Background is used to set a color or an image behind an entire web page or a specific HTML element or a small part of an element We can use the following style rules to give CSS Background Properties which are mostly used background color Used to give a specific color background image Used to give one or more images background repeat The rule is written whether to repeat the image file or not background attachment The rule is written whether the image used in the background will scroll or stay in a certain place background position The rule is where the position of the image will be written I will try to give examples of all these on one page Let s start with background color background color is the color of the back of an element And it is written like this background color h background color red Color code can also be used instead of color name If you go here you will find the names and codes of HTML color h background color background image background image background image Sets an image behind the HTML element Here we will set an image in the background of our entire site with background image For that we will write body background image url background png You have to set where the image is in brackets with url So we did above If the image and the html file are in the same folder then just enter the name of the image E g background image url highway jpg Now let s come to background repeat If our image is much smaller than our web page then it can be seen that the image is shown again and again We can turn it off if we want body background image url background png background repeat no repeat No repeat will show the image only once We can repeat a direction such as x axis or y axis if we want For example background repeat repeat x will repeat the x axis background repeat If you repeat y the y axis will repeat For more about CSS Background properties continue reading Recommended Learn About CSS Background PropertiesLearn about Text Styling in CSSCSS Shorthand Properties Useful CSS ShorthandFor more exciting tips and tricks about programming and coding please read our others articlesFind My page on Instagram stack contentFind Me on Twitter mrezaulkarim	2022-04-23 10:18:33
海外ニュース	Japan Times latest articles	Japan offers ¥500 billion to help solve water issues in Asia-Pacific	https://www.japantimes.co.jp/news/2022/04/23/national/japan-pledge-water-support/	Japan offers billion to help solve water issues in Asia PacificPrime Minister Fumio Kishida indicated his country s eagerness to support the development of high quality infrastructure using the country s cutting edge technologies	2022-04-23 19:20:43
海外ニュース	Japan Times latest articles	Japan Coast Guard searching for tour boat off Hokkaido that reported taking on water	https://www.japantimes.co.jp/news/2022/04/23/national/tourist-boat-hokkaido-flood/	Japan Coast Guard searching for tour boat off Hokkaido that reported taking on waterThe coast guard which received the report around p m said it had not found the boat named Kazu nor the people on board	2022-04-23 19:15:09
ニュース	BBC News - Home	Charity inquiry into oligarch Viateschlav Kantor, donor to royal hospital	https://www.bbc.co.uk/news/uk-61194273?at_medium=RSS&at_campaign=KARANGA	charity	2022-04-23 10:16:33
サブカルネタ	ラーブロ	渡なべ＠西早稲田、高田馬場	http://ra-blog.net/modules/rssc/single_feed.php?fid=198382	西早稲田	2022-04-23 11:30:16
北海道	北海道新聞	知床岬沖で観光船が浸水　乗員乗客２６人の安否不明	https://www.hokkaido-np.co.jp/article/673220/	管区海上保安本部	2022-04-23 19:24:29
北海道	北海道新聞	水産庁の取締船「白竜丸」　小樽港拠点化で歓迎式典　船長「地元との交流も」	https://www.hokkaido-np.co.jp/article/673265/	漁業取締船	2022-04-23 19:18:00
北海道	北海道新聞	今年最後　ファンタジー大賞２８年の歩み　小樽で資料展開始　工藤理事長講演	https://www.hokkaido-np.co.jp/article/673264/	児童文学	2022-04-23 19:15:00
北海道	北海道新聞	＜発見！コロナ下の元気企業＞虹霓舎（こうげいしゃ）アイヌ文様　切り子細工に	https://www.hokkaido-np.co.jp/article/673263/	霓舎	2022-04-23 19:12:00
北海道	北海道新聞	ロシア軍、作戦第２段階成果なし　東部の侵攻鈍化	https://www.hokkaido-np.co.jp/article/673262/	鈍化	2022-04-23 19:09:00
北海道	北海道新聞	オ３―２ロ（２３日）　オリックスがサヨナラ勝ち	https://www.hokkaido-np.co.jp/article/673261/	延長	2022-04-23 19:03:00