1.
Enrich Your Testing
Portfolio

2.
Me
● Independent consultant
● Backend & Node.js only
● Author of =>
● www.GoldbergYoni.com
● https://github.com/i0natan/no
debestpractices

3.
Problem: an ancient pyramid drives our
modern testing strategy
● Top R&D $$$ are assigned to quality and testing
● How we invest that money? Based on 10 years old model

4.
2014: It started with some provocative
tweets

5.
2018: Leading voices put some doubt

6.
Issue 1: Unit test has lower ROI (per unit)
● Would you paint a house using a mascara brush?
● Focus on exotic cases vs the critical path
Unit
Test
Integration
Tests

7.
Issue2: the sum is greater than the parts
● Integration is often where the dead bodies are covered
● “But it worked on my machine” - Poke holes in reality
?
??

8.
Issue2: the sum is greater than the parts
● Integration is often where the dead bodies are covered
● “But it worked on my machine” - Poke holes in reality
?
?
??

9.
Issue 3: E2E tests are fragile & expensive
● Get confidence for an outrageous prices
● Re-build the entire AWS on your machine is tedious

10.
Issue 4 : One technique fits all?
● Many different architecture - Data pipeline, UI meshup, deep learning
models, IOT systems, etc, etc
● Tests need to solve real-world, not theoretic problems
● Where would you write unit tests here?

11.
Solution #1: The Testing Trophy

12.
Solution #2: Other modernized pyramids
Spotify pyramid Testing quadrat

13.
Solution #3: A rich testing portfolio
● Contextualize - suit tools for problems
● Diversify - rich and holistic approach

14.
The portfolio #1: Component testing
● Problem: Finding the sweet
spot between Unit and E2E
● Good for: Independent
microservices
● Tools: HTTP interceptor (Nock),
API tester (supertest)
● Can replace: Unit tests

15.
Component testing - why I just love it
● Test what you deliver
● Use real internal resources, like db, Stub external collaborators
● Test entire flows -> Better confidence
● Less IO -> Better speed

16.
Component testing: Stub the externals,
boost the internals
Stub the
externalsBoost the
internals

17.
The portfolio #2: Consumer driven contracts
● Problem: many consumers - many
API versions, Swagger is static,
consumers don’t read the manual
● Good for: Integrations with
complex and versioned API, multi-
team microservices
● Framework: PACT
● Can replace: E2E tests

18.
Consumer driven contract: the flow

19.
PACT: The consumer expectations from the
provider microservice

20.
The provider verification code

21.
View integration status within the broker

22.
The portfolio #3: Property-based testing
● Problem: Traditional testing is based
on selective and small set of input
● Good for: Loosely-typed APIs,
serendipity
● Tools: jsverify, testcheck-js
● Can replace/improve: Unit &
integration tests

23.
Traditional testing -> manually code
every input

24.
Property based testing -> automatically
invokes every possible permutation

25.
Property based testing inside test case - example
Invoked x
times

26.
Property based testing demands a shift of mind

27.
Property based testing are great for:
● Generalize your expectations
○ E.g. Never get a price lower than 0
● Validating generic health concerns
○ E.g. HTTP returns only 200, 204, 500
○ Our code throws only valid Errors
○ Process never crash
○ No DDOS
● Great match for loose API
○ E.g. search systems, IOT
● Prepare the ground for unit testing

28.
The portfolio #4: Mutation-based testing
● Problem: Testing coverage
doesn’t measure the test
effectiveness
● Good for: Revealing bugs in
logic-heavy apps
● Tools: Stryker
● Can improve: Unit & integration
test

29.
83% coverage - isn’t this great?

30.
83% coverage and 0 expectations. This isn’t great

31.
Stryker can measure test efficiency

32.
The portfolio #5: Chaos testing
● Problem: Bad things might
come from outside
● Good for: Companies that value
resilience
● Tools: Netflix swiss army knife,
kube-monkey, node-chaos-
monkey
● Can improve: E2E tests

33.
The typical container-killer monkey

34.
Node.js in-process chaos tool

35.
Wrapping up
● Some testing tools suit your needs better
● Lean testing is a great companion for lean teams
● Wanna benefits all these goods? Enrich your testing portfolio
P.s. we haven’t discussed ‘Acceptance testing’, ‘VCR testing’, ‘Database
testing’, ‘Shadow testing’ and others