Oracle CodeOne 2019: Descending the Testing Pyramid: Effective Testing Strategies for Microservices

@crichardson Descending the test pyramid Copyright © 2019. Chris Richardson Consulting, Inc. All rights reserved Chris Richardson Founder of Eventuate.io Founder of the original CloudFoundry.com Author of POJOs in Action and Microservices Patterns @crichardson chris@chrisrichardson.net https://adopt.microservices.io

@crichardson Presentation goal Effective testing strategies for microservices

@crichardson About Chris http://adopt.microservices.io

@crichardson About Chris https://microservices.io/book 40% discount with code ctworaclecodeone19

About Chris: microservices.io Microservices pattern language Articles Example code Microservices Assessment Platform

@crichardson Agenda Overview of testing microservices Unit testing Integration testing Component testing End to end testing Testing in production

@crichardson The state of automated testing today: Oops! https://cdn.agilitycms.com/sauce-labs/white-papers/sauce-labs-state-of-testing-2018.pdf 😢

@crichardson + Marketplace is volatile, uncertain, complex and ambiguous + Businesses must innovate faster Deliver software rapidly, frequently and reliably Software

Daily Commits Use DevOps & Continuous Delivery/Deployment A highly testable and deployable architecture is essential ApplicationAutomated deployment pipeline Production Source code repository Automated testing is essential

@crichardson The problem with a large, complex monolith Time Maintainability Testability Deployability Modularity Evolvability Size/ Complexity -ilities required to be competitive Risk of disruption

The microservice architecture is an architectural style that structures an application as a set of services Each microservice is: • highly maintainable and testable • loosely coupled • independently deployable • organized around business capabilities • owned by a small team

@crichardson Autonomous service teams Order Service Automated deployment pipeline Source code repository Kitchen Service Automated deployment pipeline Source code repository Delivery Service Automated deployment pipeline Source code repository Production Orders Team Kitchen Team Delivery Team

@crichardson Microservices enable DevOps DevOps requires automated testing Complexity of microservices requires good automated testing Using the Microservice Architecture without automated testing is self-defeating AND risky http://bit.ly/msa-antipattern-ﬂying-before-walking

@crichardson What is a test? Test System under test (SUT) Veriﬁes behavior • SUT = thing being tested = class … entire application • Collection of tests = Test Suite

@crichardson The testing pyramid and microservices Unit Integration Includes consumer-driven contract tests Component End to End Classes within service A services adapters An entire service Multiple services or application Brittle, Slow, Costly Reliable, Fast, Cheap

Agenda Overview of testing microservices Unit testing Integration testing Component testing End to end testing Testing in production Unit testing Unit Integration Component End to End

@crichardson About unit tests Test Class or cluster of classes Test Double Test Double Dependency Dependency Dependen Simulates dependency SUT

@crichardson Business logic Controller POST /something GET /something/id Database Database adapter Inbound Message Adapter Repository Service Entity Value object Outbound Message Adapter Unit test Unit test Unit test Saga <<Message Channel>> <<Message Channel>> Primary focus is the business logic “algorithms" Unit testing adapters is sometimes useful Maybe unit test coordination logic

@crichardson Unit test selectively http://blog.stevensanderson.com/2009/11/04/selective-unit-testing-costs-and-beneﬁts/ Cost of unit testing = # dependencies Beneﬁt of unit testing = non-obviousness High HighLow Low Algorithms Trivial code Coordinators Overly complex code (rewrite)

Agenda Overview of testing microservices Unit testing Integration testing Component testing End to end testing Testing in production Unit Integration Component End to End

About integration testing Inbound adapters: HTTP controller … Outbound adapters: HTTP proxy DAO Messaging adapter … Integration Test Adapter Veriﬁes behavior Adapter Adapter AdapterAdapter Service

@crichardson Integration testing persistence code

@crichardson Inter-service dependencies integration testing

@crichardson Consumer-driven contract testing Verify that a service (a.k.a. provider) and its clients (a.k.a. consumers) can communicate while testing them in isolation

@crichardson Contract testing example Api Gateway Order Service Proxy Order Service Order Controller GET /orders/{id} ProviderConsumer

@crichardson Contract testing example Request from consumer Response from service Describes Written by API Gateway Team API deﬁnition by example Order Service Proxy Order Controller GET /orders/{id} ProviderConsumer

@crichardson Consumer-side contract test OrderService Proxy Order ServiceProxy Tests Use WireMock- based Order Service Test Double Conﬁgures Verify that proxy makes requests that match contract and can consume responses “service virtualization” GET /orders/{id}

@crichardson Provider-side contract test Class BaseHttp { } class HttpTest extends BaseHttp {… Spring Cloud Contract Code generates Reads Conﬁgures with mock OrderRepository Order Controller Tests Order Repository Must be consistent Verify API structure matches contracts GET /orders/{id}

@crichardson Assumption: If consumer and provider are tested independently with the same contracts Consumer and provider can communicate OrderService Proxy Order Controller Test Test

@crichardson Agenda Overview of testing microservices Unit testing Integration testing Component testing End to end testing Testing in production Unit Integration Component End to End

Goal of component testing Minimalist Verify that the container is deployable Passes health check … VS. Acceptance tests Real world/user focussed But avoid duplicating unit and integration tests Component Test Service Veriﬁes behavior In isolation

@crichardson Test process (eg. JVM) In-process component testing In-memory database Test Some Service REST API Outbound adapter, eg. Service Proxy Mock IPC, e.g. RestTemplate/Messaging Some other service Messaging API Conﬁgures mocks

@crichardson Out-of-process component testing Real Database Test Some Service REST API Mock Other Service REST API Message Broker Conﬁgures mocks Separate process, e.g Docker container Exchanges messages

About WireMock: Mockito for HTTP servers http://wiremock.org/ @Test public void shouldProxyCreateOrder() { … stubFor(post(urlEqualTo("/orders")) .willReturn( aResponse() .withStatus(200) .withHeader("Content-Type", "application/json") .withBody(expectedResponse))); … verify(postRequestedFor( urlMatching("/orders"))); }

@crichardson Running out of process component tests: $ ./gradlew componentTest = @Before/@After

@crichardson In-process vs out-of-process Beneﬁts Drawbacks In-process Simpler Faster Less realistic Out-of-process More realistic Slower More complex

@crichardson End to End testing veriﬁes behavior of application End to End Test FTGO application Order Service Consumer  Service … https://docs.cucumber.io/gherkin/

@crichardson Application Deployment pipeline Running end to end tests Order Service deployment pipeline Kitchen Service deployment pipeline Delivery Service deployment pipeline …. End to End tests Production

About scenario-based end-to- end testing Typically, BDD user scenarios = original requirements user focussed/real world Parallelization can accelerate testing BUT Duplicates tests lower down the pyramid Brittle, slow, complex Potential bottleneck that delays getting changes (e.g. bug ﬁxes) into production Use selectively based on risk My Bank App Given … When … Then … Loan Repayment Calculator Loan Document Generator Slow External Service Bottleneck

@crichardson Replace end-to-end tests with per-service (component) tests My Bank App Given … When … Then … Loan Repayment Calculator Loan Document Generator Slow External Service My Bank App Loan Repayment Calculator Loan Document Generator Slow external Service Given … When … Then … Given … When … Then … Bottleneck only for Loan Document Generator

@crichardson https://blogs.msdn.microsoft.com/seliot/2011/04/25/i-dont-always-test- my-code-but-when-i-do-i-do-it-in-production/

@crichardson Test environment != production Issues will appear in production

@crichardson Testing in production* Separate Deployment - running in production Release - available to users Test code Before releasing When releasing Automate for fast deployment, rollback and roll forward * a.k.a. Validation in production https://medium.com/@copyconstruct/testing-in-production-the-safe-way-18ca102d0ef1

Order Service V1 Order Service V2 Test deployed code before releasing: e.g. Canary release 1.Deploy V2 alongside V1 2.Test V2 3.Route test traffic to V2 4.Release V2 to a small % of production users 5.Monitor/test (latency, errors) - undo rollout if errors 6. Increase % of production traffic going to V2 7.Repeat until 100% of traffic going to V2 8.Eventually undeploy V1 Intelligent traffic router Order Service V1 Order Service V2 Monitoring system

Feature toggles/ﬂags A toggle controls which of several code paths is used Release toggle - allow incomplete code to be safely committed/ deployed during trunk based development Ops toggles - enable Ops to enable/disable features Permissioning toggles - user attribute features/experience Experiment toggles - e.g. A/B testing https://martinfowler.com/articles/feature-toggles.html

@crichardson Summary Use the microservice architecture accelerate software delivery by improving testability and deployability Using microservices without automated testing is self-defeating AND risky Accelerate the deployment pipeline by pushing testing as far down the test pyramid as possible End-to-end tests: Use selectively Replace with per-service tests as much as possible Test in production for reliable deployments/releases

@crichardson @crichardson chris@chrisrichardson.net http://adopt.microservices.io Questions? 40% discount with code ctworaclecodeone19

Oracle CodeOne 2019: Descending the Testing Pyramid: Effective Testing Strategies for Microservices

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Oracle CodeOne 2019: Descending the Testing Pyramid: Effective Testing Strategies for Microservices