The slides of my session "Unit vs. Integration Tests" I gave at our Softwerkskammer Meetup Munich. Abstract: Unit and integration test fan boys have been fighting against each other since the early days of TDD. Nevertheless in the last years the test pyramid has become the common sense strategy for automated tests synthesizing both approaches in an economic ratio. Unfortunately in practice the vague and abstract concept leaves us alone with a lot of remaining questions. I will start the session introducing the test pyramid strategy and the strengths and weaknesses of the different kinds of tests followed by implementation approaches valuable for real life. Then we will split up into small groups and discuss there what in our current projects works well for us and work together on how we can approach remaining challenges. In the end we will come together again and exchange our solutions in the full audience.

1. Unit vs. Integration Tests
Softwerkskammer Meetup Munich
@codecentric
18.06.2015
David Völkel
@davidvoelkel

2. Unit vs. Integrated Tests
Isolated integratedvs.

3. Which do you prefer?
Isolated Integrated
1 2 3 4 5

4. Agenda
● Theory
● Unit vs. Integration Tests
● Test Pyramid
● How to achieve it
● Workshop
● What works well in our projects?
● Hardest challenges?
● How to address them?
● Another beer

5. Expensive Integrated Tests
Isolated Integrated
Creation &
Maintenance
cheap expensive
Feedback fast slow
Finding Errors easy difficult
Fragility minimal high
Significance for User medium high
4
n
+
m
n
*
m

6. Unit under test?
Isolated Integrated
Strengths Complex logic
(„combinatorial
explosion“),
conditionals, breadth
Integration, data
flow, depth

7. Test Pyramid
UI
Service
Unit
DegreeofIntegrationBy Mike Cohn

8. No: Test Pyramids!?!
By Mike Cohn

9. ?
?
Unit

10. Orthogonal decomposition
By Mike Cohn
.
IntegratedTests
Isolated Tests &

11. Business Dimension
Acceptance Tests == UI-Tests?
Inspired through "the testing iceberg“ by Seb Rose / Matt Wynne
Acceptance Tests
Technical Tests
Business Domain
DegreeofIntegration .

12. Split up Acceptance Tests
Acceptance Tests
UI Domain Rules

13. Example Email Validation
N x integrated web tests
Input Output
„valid@email.de“ „Email OK“
„mail.without@tld“ „Email invalid“
„mail.without.at.de“ „Email invalid“
„@without-user.de“ „Email invalid“
…
valid

14. Example Email Validation
1 x integrated web tests
N x isolated tests
valid
Input Output
„valid@email.de“ „Email OK“
„mail.without@tld“ „Email invalid“
„mail.without.at.de“ „Email invalid“
„@without-user.de“ „Email invalid“
…

15. UI Test Pyramid
UI Test !=
End2End Tests
E2E
Compo
nent
Unit
DegreeofIntegration

16. (UI) End2End Tests
Fully integrated down to the backend
for
• backend interaction
• few logic (CRUD)
• simple workflows
• hardly testable legacy UI
E2E
Compo
nent
Unit
Back-
end

17. Gmail Example
E2E
Compo
nent
Unit
Minimal workflow

18. UI-Layer
component test
● testability required
● fat client
● SPA + REST
● server-side rendering?
E2E
Compo
nent
Unit
UI
Mock
Back
end

19. UI-Layer
for
• session status
• complex UI workflows
• workflows with few backend-
interaktion
E2E
Compo
nent
Unit
UI
Mock
Back
end

20. Gmail Example
E2E
Compo
nent
Unit
Mail editing

21. UI Unit Tests
for complex logic
value rendering
MVP: Presenter logic
Address example:
„D-80687, München, Elsenheimerstraße 55a“
„-, München, Elsenheimerstraße 55a“?
E2E
Compo
nent
Unit
UI

22. Resumee
UI
Service
Unit
Test Pyramid
• Integrated Tests: Integration &
Depth
• Isolierte Tests: Logic & Breadth
Orthogonal Decomposition
• Split up Acceptance Tests
• Business Rules
• UI
• E2E, UI Layer, UI Unit Tests

23. Workshop Agenda
● Round 1: current state in your project
● Successful solutions?
● Hardest challenges?
● Show & tell
● Round 2
● how can we improve?
● Show & tell
● Retrospective

24. Retrospective

25. License
Creative Commons Attribution-ShareAlike 3.0
https://creativecommons.org/licenses/by-sa/3.0/de/