tdd: what is it good for?

TDDwhat is it

good for?

David Simons

Developer @

Softwire

<3 Databases

Part-time Elf

Automated Testing

Functional Testing

Stress Testing

Unit Testing

Flight Availability

Repository

Flight Availability

Service

Flight Availability

Repository

Flight Availability

Service

Test Double

Flight Availability

Service

Flight Availability Repository

Flight Availability

Service

Flight Availability Repository

isAvailable?

Flight Availability

Service

Flight Availability Repository

no

What is TDD?

Test Driven Development

Failing TestMake it PassRefactor

Failing TestMake it PassRefactor

Failing TestMake it PassRefactor

Failing TestMake it PassRefactor

Failing TestMake it PassRefactor

Failing TestMake it PassRefactor

Failing TestMake it PassRefactor

Failing TestMake it PassRefactor

Failing TestMake it PassRefactor

Failing TestMake it PassRefactor

Failing TestMake it PassRefactor

Failing TestMake it PassRefactor

Failing TestMake it PassRefactor

All possible tests pass

@Unroll def "Fib Number #input is #result"() { given: def fibCalc = new FibCalculator() expect: fibCalc.calculate(input) == result }

where: input| result 0 | | 0

int calculate(int input) { 0 }

where: input| result 0 | 0

int calculate(int input) { 0 }

where: input| result 0 | 0 1 | 1

int calculate(int input) { input }

where: input| result 0 | 0 1 | 1

int calculate(int input) { input }

where: input| result 0 | 0 1 | 1 2 | 1

int calculate(int input) { if(input == 0) { return 0 } 1 }

where: input| result 0 | 0 1 | 1 2 | 1

int calculate(int input) { if(input == 0) { return 0 } 1 }

where: input| result 0 | 0 1 | 1 2 | 1 3 | 2

int calculate(int input) { if(input == 0) { return 0 } if(input <= 2) { return 1 } 2 }

where: input| result 0 | 0 1 | 1 2 | 1 3 | 2

int calculate(int input) { if(input < 2) { return input } 1 + calculate(input – 2) }

where: input| result 0 | 0 1 | 1 2 | 1 3 | 2

int calculate(int input) { if(input < 2) { return input } 1 + calculate(input – 2) }

where: input| result 0 | 0 1 | 1 2 | 1 3 | 2 4 | 3

int calculate(int input) { if(input < 2) { return input } calculate(input - 2) + calculate(input – 1) }

where: input| result 0 | 0 1 | 1 2 | 1 3 | 2 4 | 3

The Benefits

Breaking Down

Problems

Testing Anti-Patterns

Regression Testing

DHH

“the test-first rhetoric got louder and angrier”

“look at what that approach is doing to the integrity of your system design”

(I had to

do this)

Is TDD Dead?

Added Complexity

Dogmatism

TDDis it dead?

any

questions?

@SwamWithTurtles