Applying T est Driven Development (TDD) with Integration T ests - - PowerPoint PPT Presentation

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Applying T est Driven Development (TDD) with Integration T ests - - PowerPoint PPT Presentation

Sep 04, 2022 130 likes •363 views

Applying T est Driven Development (TDD) with Integration T ests Steve Gordon MICROSOFT DEVELOPER TECHNOLOGIES MVP @stevejgordon www.stevejgordon.co.uk t h s Test Driven Development (TDD) Overview Applying TDD with integration tests

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@stevejgordon www.stevejgordon.co.uk

MICROSOFT DEVELOPER TECHNOLOGIES MVP

Steve Gordon

Applying T est Driven Development (TDD) with Integration T ests

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t h s

Test Driven Development (TDD) Applying TDD with integration tests Defining external boundaries Creating fakes of external services Replacing services with fakes by customizing the test client

Overview

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Test Driven Development

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Retrospective Tests

Tests written after implementation code Possible to miss test cases Possible to assert on incorrect output

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Test Driven Development

Tests come before implementation code Test coverage aligned to requirements Simplified implementation code Promotes refactoring to clean code

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Red Green Refactor

Test Driven Development Cycle

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Mental shift from retrospective testing Requires perseverance to become productive

TDD Paradigm

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Demo

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Apply test driven development

  • Write a failing test (red)
  • Make the test pass (green)
  • Refactor the code
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Add GET endpoint /api/stock/total Return JSON (application/json) response Total is count of all stock of all products

{ "stockItemTotal": 100 }

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Demo

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Continue development with TDD

  • Test and implement a final requirement

Define a boundary for integration tests Create a fake of a dependency

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High-level Architecture

SDK

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Code Dependency Chain

IDatabaseClient<T> ICloudDatabase IProductDataRepository StockController

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Code Dependency Chain

IDatabaseClient<T> ICloudDatabase IProductDataRepository StockController

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Code Dependency Chain

IDatabaseClient<T> ICloudDatabase IProductDataRepository StockController

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Advantages

Integration tests run fully in memory Can be run often during development Easy to run during continuous integration

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Demo

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Customize the test client using WithWebHostBuilder

  • Register a fake service
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ISe IServic iceColle llectio ion ISe IServic iceColle llectio ion ICloudDatabase -> CloudDatabase

Service Registration Order

ISe IServic iceColle llectio ion ICloudDatabase -> CloudDatabase ISomeOtherService -> SomeOtherService ISe IServic iceColle llectio ion ICloudDatabase -> CloudDatabase ISomeOtherService -> SomeOtherService ICloudDatabase -> FakeCloudDatabase Startup.cs

ConfigureServices

StockControllerTests.cs

ConfigureTestServices

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var client = _factory.WithWebHostBuilder(builder => { builder.ConfigureTestServices(services => { services.RemoveAll<IFoo>(); services.AddSingleton<IFoo,FakeFoo>(); }); }).CreateClient();

Managing Registered Services

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Learned about Test Driven Development Applied the TDD cycle

  • Wrote a failing test
  • Implemented with minimal code
  • Confirmed the test passed
  • Refactored where necessary

Defined external boundary for testing Created a fake for a service Customized the test client to use the fake

Summary

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Up Next: Writing Integration Tests for ASP.NET Core Web APIs: Part 2