Slide 1

Testing Strategies for Micro-services Architecture

Ketan SoniJesal Mistry

June 2014

Brief IntroThere has been a shift in service based architectures over the last few years towards smaller, more focussed "micro" services. There are many benefitswith this approach such as the ability to independently deploy, scale and maintain each component.

Our team has spent the last two years building and deploying more than 10microservices into production, and we plan to create a few more.Here we would like to discuss a number of approaches and testing strategies for managing the testing of independently deployable components.

What is a micro-service?

Ask the audience

Example

I want to purchase a product from an e-commerce website

Monolithic system

MasterCard / VisaLogistics

CartCatalogAuthenticationPaymentFulfilment

E-commerce website

Unixphilosophy:

Write programs that doone thing and do itwell.

A system built using micro-services is a system that is built up of small, lightweight services, where each performs a single function. The services are arranged in independently deployable groups and communicate with each other via a well defined interface and work together to provide business value.

Micro-Services system

MasterCard / VisaLogistics

Cart Service

Payment ServiceAuthentication ServiceFulfilment Service

Catalog Service

E-commerce website

Challenges in testing

Distributed system complexity

Inter service communication

Asynchronous nature

Dependency management

Challenges in testing

- as good as having different teams, working on different services

Testing Strategies

Top-down

Big Bang

Hybrid / Context Driven

Bottom-up

- top down- having UI test- brittleness- high maintenance- slow feedback- big bang- testing after the fact (app is ready & done)- hybrid/context- mix of approaches- bottom up

Our Approach

Bottom-up testing Test the domain

Tests closer to the code

Integrate Early

Use Mocks / Stubs

Focus is on Test Pyramid

Helps visualize/categorize test coverage better

Test Pyramid

Unit

Contract

E2E Integration

UI

Consumer Driven Contract

Manual / Exploratory

Bottom-up testing

Test Pyramid

Unit

Contract

E2E Integration

UI

Consumer Driven Contract

Manual / Exploratory

Unit Test Layer

Test the domain

Should focus on the code under test

Maximum test coverage

Unit Test Layer

Authentication ServicePayment ServiceCatalog Service

Unit tests

- addItem- removeItem- verifyCreditCardCart ServiceFulfilment Service

Test Pyramid

Unit

Contract

E2E Integration

UI

Consumer Driven Contract

Manual / Exploratory

Contract Test Layer

Test one end-point at a time

Treat the service as a black box

These tests are end to end within the bounds of the service

Assertion are on response e.g. JSON body

Stub out the dependencies

Contract Test Layer

Contract Test Layer

Contract Test Layer

Contract tests

Add Item to cart

POST /cart/{:product_id}

HTTP Request

HTTP Response

JSON

....

Cart ServiceMockAuthentication Service

MockCatalog ServiceMockFulfilment ServiceMockPayment Service

Unit

Contract

E2E Integration

UI

Consumer Driven Contract

Manual / Exploratory

Test Pyramid

The goal of these tests is to execute as much of the application code as possible as quickly as possible. The basic idea is to run up all your services in memory and connect them via in memory http pipes.

End to End Integration Test layer

Test End to End user journey to make sure that the business flow works as expected

These covers interaction of all the available services

End to End Integration Test Layer

End to End Integration Test layer

E2E Integration tests

Cart ServicePlace an order

Payment ServiceAuthentication ServiceCatalog ServiceFulfilment ServiceVerify that the order is placed

MockLogisticsMockMastercard

End to End Integration Test Layer

Test Pyramid

Unit

Contract

E2E Integration

UI

Consumer Driven Contract

Manual / Exploratory

Consumer Driven Contract Test layer

In case of third-party system, we had tests to make sure that external systems behave the way we expect them to.

Consumer Driven Contract Test Layer

Consumer Driven Contract Test layer

Consumer Driven Contract tests

Verify Credit Card

MasterCard / VisaService

Consumer Driven Contract Test Layer

Verify Credit Card

HTTP Request

HTTP Response

Success

Test Pyramid

Unit

Contract

E2E Integration

UI

Consumer Driven Contract

Manual / Exploratory

UI Test Layer

For the UI layer, we wrote tests for the End to End user journey which also covered the external 3rd party interactions

UI tests were minimal

UI Test Layer

User Interface Journey tests

Authentication ServiceFulfilment ServicePayment ServiceCart Service

As a userI should be able to purchase a mobile from a websiteUIMasterCard / VisaLogistics

Test Pyramid

Unit

Contract

E2E Integration

UI

Consumer Driven Contract

Manual / Exploratory

References

Logging

Inter - Service effects

Gracefully handle errors

Look & Feel

Manual / Exploratory

References

http://en.wikipedia.org/wiki/Unix

http://davidmorgantini.blogspot.co.uk/2014/03/microservices-effective-testing.html

http://martinfowler.com/articles/microservices.html

https://github.com/tobyclemson

References

Questions ?