Building a testing culture

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TESTING building CULTURE

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https://ordepdev.me/posts/test-driven-developers

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THIS IS NOT ABOUT TDD!

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@ordepdev

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First of all Why testing?

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“It’s time for software developers to take up the mantle of responsibility for what they produce.

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Testing is the engineering rigour of software development.

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Responsibility — the state or fact of being accountable or to blame for something.

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Rigour — the quality of being extremely thorough and careful.

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Software Engineering

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An engineering discipline that is concerned with all aspects of software production.

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MUCH MORE THAN CODING!

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Types of Bad Software Projects

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1. Without tests.

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Zero Automated Tests.

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ZERO!

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Lack of professionalism?

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Lack of skills?

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Lack of knowledge?

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Lack of time to test?

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It can be all of them.

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What about software quality?

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Relax, we test all features with manual testing.

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2. With Wrongly Designed Tests..

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Testing is HARD.

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https://twitter.com/codepipes/status/987934900111138816

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Testing pitfalls: coupling.

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Implementation Boundary Testing Boundary

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Implementation Boundary Testing Boundary ✅ ✅ ✅ ✅ ✅ ✅ ✅ ✅ ❌ ❌

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Uncertainty and Doubt.

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Implementation Boundary Testing Boundary ✅ ✅ ✅ ✅ ✅ ❌ ❌ ❌ ❌ ❌

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Testing pitfalls: performance.

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Taking too much time? — that’s a no run.

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Types of Testing

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1. Testing after the implementation.

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2. Testing during the implementation.

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3. Testing that reproduce bugs.

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It’s our job to build a testing culture!

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But how?

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5 rules.

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1. Every change must have tests.

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50 100 150 200 Development Unit Tests Functional Tests System Tests Production The cost of bugs

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Bugs in production are embarrassing and costly.

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2. Write more than unit tests.

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https://twitter.com/pwlporto/status/999258562370170880

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We do not know how much an increase in coverage can decrease the number of defects.” “

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https://ordepdev.me/posts/code-coverage

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Mutation testing!

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def add(x,y) x + y end def add(x,y) x - y end Source Code Mutation

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Property-based testing! https://hypothesis.works/articles/quickcheck-in-every-language

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http://blog.jessitron.com/2013/04/property-based-testing-what-is-it.html

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Contract testing! https://martinfowler.com/bliki/ContractTest.html

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https://ordepdev.me/posts/boost-your-conﬁdence-with-consumer-driven-contracts

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Model-based testing! http://mit.bme.hu/~micskeiz/pages/modelbased_testing.html

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Instead of writing hundreds of test cases, write an abstract model of the system and generate a set of test cases.” “

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Formal methods! https://www.infoq.com/presentations/aws-testing-tla

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Formal methods use mathematical proof as a complement to system testing in order to ensure correct behavior.” “

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3. Bug ﬁxing must have tests.

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Don’t repeat the same bug hunting — write a test!

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4. Testing code must be reviewed.

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A well-designed test suite is much easier to read, understand and evolve.

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Testing code is production code!

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5. Test suites must be consistent.

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L12. assertEquals(input, expectation); L35. assertEquals(expectation, input); L43. assertThat(input).isEqualTo( expectation); Assertions

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L12. assertEquals(input, expectation); L35. assertEquals(expectation, input); L43. assertThat(input).isEqualTo( expectation); Assertions

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L12. createEntity L35. create_withValidPayload_success L43. create_withValidPayload_shouldPersistEntity Test Methods

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L12. createEntity L35. create_withValidPayload_success L43. create_withValidPayload_shouldPersistEntity Test Methods

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We must share the same values, practices, and tools.

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Enforce them through code reviews, static analysis, and style checking tools.

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5+1.Test suites must be visible.

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A failed test is a failed build!

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Wrapping up.

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People who are successful at automating tasks tend to work this way in every aspect of their jobs. It is just how they work; it is part of their culture. “ ”