How to write test in node.js

How to write test in node.js

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  How to writetest in Node.js Jason Lin (starrlingo@gmail.com) 2017/08 1
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  Why • Why weneed to write test? – Few questions • How do you know the status of the system? • How do you know the code you commit meet the requirement? • How do you know the code you commit won’t break other module? • Side effect? – Problems: Manual test is trivial and time consuming – Solution: write test and make it run automatically 2
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  What • Testing methodologies 3 Testthe individual component Test the component groups Test the integrated systems Test the final system Reference: https://www.inflectra.com/ideas/topic/testing-methodologies.aspx
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  What • Testing methodologies –Unit Test • Test on isolated component (public) • Shouldn’t have dependencies (file, db, 3rd Party Lib, …) – Integrate Test • Testing on multiple components • Verify the interaction between components • It may rely on dependencies – System Test • Concerned with the behavior of the full system 4
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  What • Development process –TDD (Test Driven Development) • Write test first • Just meet the requirement • Never over-design 5 Reference: https://www.allaboutcircuits.com/technical-articles/how-test- driven-development-can-help-you-write-better-unit-tests/
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  What • Development process –BDD (Behavior Driven Development) • Develop software correctly and develop correct software • Focused on the business behaviors • Spec as test case – PM and target user wrote stories together – PM and engineers wrote the scenarios together • Story (gherkin syntax) • Scenario (gherkin syntax) 6 As a <type of stakeholder> I want <a feature> So that <some goal can be met> Given <a context> When <an event happens> Then <an outcome should occur>
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  What • Development process –BDD (Behavior Driven Development) • Example 7 Feature: QIoT Backup As an administrator, I want to backup the whole QIoT So that I can restore the system Scenario: Backup QIoT Given the administrator logged in to QIoT When administrator press the backup button Then the backup zip file should be downloaded automatically
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  What • Development process –BDD + TDD 8 Reference: https://www.getzephyr.com/insights/collaboration-backbone-agile- testing
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  How • How canwe write test in Node.js? – Test Framework • Mocha / Jasmine / Ava • Cucumber – Assertion Library • Chai – Test Double Library • Sinon / Mockery / Proxyquire 9
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  Test Framework -Mocha • What is Mocha – Run on Node.js/Browser – Supports BDD/TDD – Choose any assertion library – Choose any mocking library – Asynchronous function and promise function support – Highlights slow tests 10
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  Test Framework -Mocha • How to install & run Mocha 11 Testing Result:
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  Test Framework -Mocha • How to write test with Mocha – BDD style (default) 12
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  Test Framework -Mocha • How to write test with Mocha – TDD style 13
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  Test Framework -Cucumber • Features – Support Node.js / Java / Ruby – Deliver executable spec document – Support Gherkin DSL syntax • Example – 1. Installation: npm install cucumber – 2. Wrote feature file 14 features/grocery.feature
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  Test Framework -Cucumber • Examples – 3. Generate template • ./node_modules/cucumber/bin/cucumber.js – 4. Implement test case by template 15 features/step_definitions/grocery.js
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  Test Framework -Cucumber • Examples – 5. Run test • ./node_modules/cucumber/bin/cucumber.js 16
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  Test Framework • Mochaor Cucumber? – Mocha are friendly to programmers • Focus on test case – Cucumber are friendly to non-programmers • Deliver executable spec 17
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  Assertion Library -Chai.js • Run on Node.js/Browser • Provide there ways of assertions 18
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  Test Double • Whatis test double? – Replace the target object for testing purpose – Type • Dummy: passed around but never actually used • Stub: Provide a canned response to method calls • Mock: Verifies behavior to a method (Stub + expected) • Spy: Proxy to real objects and record all kinds of things • Fake: Business behavior simulators 19
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  Test Double • Sinon.js –spy/stub/mock library – Installation: npm install sinon – Spy: 20
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  Test Double • Sinon.js –Stub – Mock 21