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Locking Tests vs. TDD Icons made by Roundicons from www.flaticon.com

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● A Functional Test describes a functionality ● A Unit Test locks an implementation Prejudice #1 Icons made by Freepik from www.flaticon.com

● A Functional Test describes a behaviour ● A Unit Test locks an implementation Prejudice #1 Icons made by Roundicons from www.flaticon.com All tests describe the expected public behaviour Only the audience and the size of the covered area vary

Only functional tests have 3 steps: ● Given ● When ● Then Prejudice #2 Icons made by Freepik from www.flaticon.com

Only functional tests have 3 steps: ● Given ● When ● Then Prejudice #2 Icons made by Roundicons from www.flaticon.com All tests follow the narrative structure: ● Given = Arrange ● When = Act ● Then = Assert Setup Catalyst Resolution

Prejudice #3 Icons made by Freepik from www.flaticon.com Checking the number of calls to all mocked methods increases my confidence. ->expects($this->exactly(1))->method('xxx') ->shouldBeCalledTimes(1)

Prejudice #3 Checking the number of calls to all mocked methods increases my confidence ->expects($this->exactly(1))->method('xxx') ->shouldBeCalledTimes(1) Icons made by Roundicons, Smashicons from www.flaticon.com ● Blurs the intent of the test ● Locks implementation details ● Impossible to write first

What to test ?

Prejudice #4 Icons made by Freepik from www.flaticon.com I can mock the libraries used on the Infrastructure side : ● Http : Guzzle… ● Database : Doctrine, Eloquent…

Prejudice #4 Icons made by Roundicons, Smashicons from www.flaticon.com I can mock the libraries used on the Infrastructure side : ● Http : Guzzle… ● Database : Doctrine, Eloquent… ● Coupled with the usage details of the lib ● Assumptions about the way it behaves ● Impossible to write first

Infrastructure : Integration Tests Icons made by Freepik, Smashicons, Roundicons from www.flaticon.com

Prejudice #5 Icons made by Freepik from www.flaticon.com Functional Test = necessarily end to end

Prejudice #5 Icons made by Roundicons, smashicons from www.flaticon.com Functional Test = necessarily end to end ● Slow ● Brittle ● Difficult to maintain ● Harder to write first ● Locks Infrastructure choices too soon Suggestion : mock Secondary Ports

Icons made by Freepik from www.flaticon.com Suggestion

I must know the splitting between my classes before I write my tests Prejudice #6 Icons made by Freepik from www.flaticon.com

I must know the splitting between my classes before I write my tests Prejudice #6 Icons made by Roundicons from www.flaticon.com ● Prod classes splitting != test classes splitting ● Start with an area with a known boundary

Icons made by Freepik from www.flaticon.com 1st test: area with a known boundary

Prejudice #7 Icons made by Freepik from www.flaticon.com If I don't mock my Entities / DTOs, too many tests will break if I add a field

Prejudice #7 Icons made by Roundicons from www.flaticon.com If I don't mock my Entities / DTOs, too many tests will break if I add a field ● Use test Factori(es) with optional fields ● Getter not covered ? I remove it

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