Testing Java Microservices with Consumer-driven contracts Andrew - - PowerPoint PPT Presentation

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testing java microservices with consumer driven contracts
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Testing Java Microservices with Consumer-driven contracts Andrew - - PowerPoint PPT Presentation

Aug 16, 2023 762 likes •1.54k views

Testing Java Microservices with Consumer-driven contracts Andrew Morgan @mogronalol Microservices testing is hard Consumer driven contract testing About Me Independent Consultant specialising in microservices & continuous delivery

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Testing Java Microservices with Consumer-driven contracts

Andrew Morgan @mogronalol

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Microservices testing is hard

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Consumer driven contract testing

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Andrew Morgan @mogronalol

  • Independent Consultant

specialising in microservices & continuous delivery

  • PluralSight Author
  • InfoQ Editor

About Me

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  • Introducing microservices testing

challenges

  • Consumer-driven contract testing
  • verview
  • Following through the workflow

with Spring Cloud Contract

  • Advanced consumer-driven

contract concepts

Agenda

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  • Introducing microservices testing

challenges

  • Consumer-driven contract testing
  • verview
  • Following through the workflow

with Spring Cloud Contract

  • Advanced consumer-driven

contract concepts

Agenda

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Payments Accounts Loans

What are Microservices?

Rewards

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HTTP HTTP

Payments Accounts Loans

What are Microservices?

Rewards

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Messaging HTTP HTTP

Payments Accounts Loans

What are Microservices?

Rewards

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The root cause of testing challenges

Payments

REST API

Booking

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End-to-end Testing Microservices

Automated tests Browser or other UI Environment

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Build time Debuggability Infrastructure cost Operations Flakiness Distributed monolith

Disadvantages of End-to-end Testing

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Automated tests Microservice Mock or Stub of Dependency

Mocking or Stubbing Dependencies

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False positives Staleness Difficult to maintain

Disadvantages of Mocking or Stubbing

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The Weak Feedback Loop

Run individual microservice tests Build and deploy to stage End-to-end test False positives Release Slow and flaky

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  • Introducing microservices testing

challenges

  • Consumer-driven contract testing
  • verview
  • Following through the workflow

with Spring Cloud Contract

  • Advanced consumer-driven

contract concepts

Agenda

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What is Consumer-driven Contract Testing?

Fills the microservices testing gap Continuous testing against contracts Consumers drive the implementation of providers Independently testable and releasable microservices

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???

Test Architecture Overview

Consumer Provider

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Key Contract Characteristics

An agreed interaction between microservices Continuously tested No specific protocol Not the same stubbing! Definitely not API documentation!

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What is an Interaction?

Scenario: Should return no flights between London and Paris

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What is an Interaction?

Scenario: Should return no flights between London and Paris Required Request: GET /flights?from=London&to=Paris

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What is an Interaction?

Scenario: Should return no flights between London and Paris Required Request: GET /flights?from=London&to=Paris Given Response: 200 []

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The Consumer Side

Automated tests Consuming Microservice Stub of provider microservice Generates The interaction our test depends on

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The Provider Side

Pre-defined contract Providing Microservice Contract verification tests Generates

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Fast and reliable feedback Less money spent on infrastructure API delivers exactly what is required Understanding dependency hell No stale stubs Easy to work in parallel

The Benefits

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  • Introducing microservices testing

challenges

  • Consumer-driven contract testing
  • verview
  • Following through the workflow

with Spring Cloud Contract

  • Advanced consumer-driven

contract concepts

Agenda

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Spring Cloud Contract Overview

JVM-based CDC framework Spring Boot Integration Groovy Based Contract Definition Language Message-driven and HTTP-driven interactions

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Credit Card Application Feature

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Credit Card Application Feature

JUnit Test Credit card applications service Credit score service

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Credit Card Application Feature

JUnit Test Credit card applications service Credit score service

Applies for credit card

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Credit Card Application Feature

JUnit Test Credit card applications service Credit score service

Calculates credit score

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Credit Card Application Feature

JUnit Test Credit card applications service Credit score service

Accepts or rejects based

  • n credit score
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Following the CDC Workflow

Write a failing test Define Contract Build stubs Make tests pass Build verification tests Make tests pass

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Following the CDC Workflow

Write a failing test

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A Failing Test

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A Failing Test

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A Failing Test

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Implementing Our Endpoint

JUnit Test

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JUnit Test Credit card applications service

Implementing Our Endpoint

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JUnit Test Credit card applications service Credit score service

Does not exist

Implementing Our Endpoint

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JUnit Test Credit card applications service Credit score service

Implementing Our Endpoint

Fails here

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Following the CDC Workflow

Write a failing test Define Contract

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Contract Definition Language

Request made by our test Response expected by our test

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Following the CDC Workflow

Write a failing test Define Contract Build stubs

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Stub Generation

Contract Spring Cloud Contract Plugin Stub Jar

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wiremock.org

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Following the CDC Workflow

Write a failing test Define Contract Build stubs Make tests pass

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The Stub Runner

Download given stubs Boots WireMock Imports stubs into Wiremock

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From a Failing Test

Unit test Credit card applications service Credit score service Fails here

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…to a Passing Test

Unit test Credit card applications service Spring Cloud Contract Stub Passes here

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Following the CDC Workflow

Write a failing test Define Contract Build stubs Make tests pass Build verification tests

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Provider Test Generation

Contract Spring Cloud Contract Plugin Verification Tests

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Following the CDC Workflow

Write a failing test Define Contract Build stubs Make tests pass Build verification tests Make tests pass

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From Failing…

Contract Verification Tests Credit score service

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To Passing…

Contract Verification Tests Credit score service Implement me

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  • Marcin Grzejszczak

“Consumer-driven contracts are like TDD applied at the API level.”

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  • Introducing microservices testing

challenges

  • Consumer-driven contract testing
  • verview
  • Following through the workflow

with Spring Cloud Contract

  • Advanced consumer-driven

contract concepts

Agenda

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Does this only work with exact comparisons?

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Regex JSON XML XPath Subsets Starts with Ignore casing More

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What about messaging?

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Message-driven CDC

Consumer Provider

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Message-driven CDC

Consumer Provider Broker

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Why Messaging?

Message schemas and queues are shared Asynchronous failures are a debugging nightmare! Brokers are slow

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Where do we store our contracts?

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Contract Repository

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Contract Repository

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Talk Summary

Don’t build and test microservices like a monolith Consumer-driven contracts promote independence Leverage frameworks like Spring Cloud Contract and Pact

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https://www.pluralsight.com/profile/author/andrew-morgan

Questions?

@mogronalol