The document discusses the test pyramid approach for testing microservices. It recommends the following distribution of tests: - Unit tests should make up 70-75% of all tests and provide isolated testing of individual modules. - Integration tests should be 10-15% and test the links between modules. - Component/workflow tests should be 7-8% and test fully deployed services in isolation. - End-to-end tests should be 3-5% and test collaboration between multiple services for business processes. The document provides examples of different types of tests and their value in testing microservices applications. It emphasizes testing services in isolation as much as possible for faster test execution.

1. Test Pyramid
In
µServices Context
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2. Example Overview

3. Example Overview
Fraud Check
Service
Paymen
t
Service

4. Example Overview
Fraud Check
Service
Paymen
t
Service

5. Example Overview
Fraud Check
Service
Paymen
t
Service
/pay

6. Example Overview
Fraud Check
Service
Paymen
t
Service
/check
/pay
Verification
Servic
e
1. Address Verificatio
n
2. CVV Verification

7. Example Overview
Fraud Check
Service
Paymen
t
Service
/check
/pay
fraudStatus
{pass, fail, suspicious}
Verification
Servic
e
1. Address Verificatio
n
2. CVV Verification

8. Example Overview
Fraud Check
Service
Paymen
t
Service
/check
/pay
fraudStatus
{pass, fail, suspicious}
Verification
Servic
e
1. Address Verificatio
n
2. CVV Verification
Save
Transaction

9. Example Overview
Fraud Check
Service
Paymen
t
Service
/check
/pay
fraudStatus
{pass, fail, suspicious}
transactionReference
{accepted, rejected}
Verification
Servic
e
1. Address Verificatio
n
2. CVV Verification
Save
Transaction

10. Test Pyramid

11. Test Pyramid

12. Test Pyramid
Unit Tests ~70-75%

13. Test Pyramid
Unit Tests
Integration Tests
~70-75%
~10-15%

14. Test Pyramid
Unit Tests
Integration Tests
Work
fl
ow Tests
~70-75%
~10-15%
~7-8%

15. Test Pyramid
Unit Tests
Integration Tests
Work
fl
ow Tests
E2E
Tests
~70-75%
~10-15%
~7-8%
~3-5%

16. Test Pyramid
UI
Unit Tests
Integration Tests
Work
fl
ow Tests
E2E
Tests
~ 1-2%
~70-75%
~10-15%
~7-8%
~3-5%

17. Test Pyramid
UI
Unit Tests
Integration Tests
Work
fl
ow Tests
E2E
Tests
~ 1-2%
~70-75%
~10-15%
~7-8%
~3-5%
Manual

18. Test Pyramid
UI
Security
Tests
Unit Tests
Integration Tests
Work
fl
ow Tests
E2E
Tests
~ 1-2%
~70-75%
~10-15%
~7-8%
~3-5%
{
Manual

19. Test Pyramid
UI
Security
Tests
Unit Tests
Integration Tests
Work
fl
ow Tests
E2E
Tests
Capacity
Tests
~ 1-2%
~70-75%
~10-15%
~7-8%
~3-5%
{
{
Manual

20. Inverted Test Pyramid
Manual
E2E/Work
fl
ow
Tests
Integration
Tests
UTs

21. µServices Test Pyramid
Image Source: https://martinfowler.com/articles/microservice-testing/#conclusion-test-pyramid

22. Value from Unit Tests
• Feedback on each of the core modules of the
system.
• All modules are tested in isolation.
• Sociable (Classical TDD)
• newify the collaborators
• Solitary (Mock Style TDD)
• Mock the collaborators
Image Source:
https://www.isro.gov.in/sites/default/
fi
les/
fl
ipping_book/26-SI-Oct-Dec-94/
fi
les/assets/common/downloads/publication.pdf
Image Source: https://www.isro.gov.in/launchers/pslv

23. Value from Integration Tests
• Feedback on Logic contained within Integration modules.
• It actually means to test one integration point at a time - the link
with the other “out-of-process” dependency.
• Examples - Queues, Databases, External services,
Filesystems, etc…
• You may use
• In-Memory data-store
• External stub-services
• Test Containers.
Image Source: https://en.wikipedia.org/wiki/Polar_Satellite_Launch_Vehicle

24. Value from Component Tests
• Feedback on how the Microservice correctly implements the required business logic/
functionality
• Test exercises fully deployed artifact.
• More coarse grained than Unit and Integration Tests
• Testing Microservice isolated from its External Dependencies (Faster test runtimes)
• In-Process
• Instantiate full Microservice in-memory by using in-memory test-doubles and/or data-
stores
• Less moving parts implies less build complexity and hence faster execution times.
• Out-Of-Process
• All interaction points make real network calls.
• You may use external data-store and/or external stub-services and/or Test Containers.
Image Source: https://space
fl
ight101.com/pslv-c31/pslv-rocket-set-to-launch-
fi
fth-indian-navigation-satellite-on-wednesday/

25. Value from End-to-End Tests
• Feedback on how many Microservices collaborate
together correctly to ful
fi
l larger business process or
end-to-end
fl
ows.
• Write tests as User Journeys as a DSL (can use
Cucumber)
• Rely on Infra-structure as Code.
https://en.wikipedia.org/wiki/Polar_Satellite_Launch_Vehicle

26. Show me the code, now!
• Links
• https://github.com/DhavalDalal/fraud-checker-service
• https://github.com/DhavalDalal/payments-service
• Additional Reference to Test Containers and Spring Integration
• https://github.com/DhavalDalal/TestContainers-Spring

27. References
• Testing Strategies in a Microservice Architecture - https://
martinfowler.com/articles/microservice-testing
• Continuous Delivery - Jez Humble and Dave Farley
• https://www.slideshare.net/nashjain/inverting-the-testing-pyramid