Manuela Munaretto, Gabriele Lana, Filippo Liverani - Women super code lab – Improve your skills with TDD Pair Programming code session | Codemotion Milan 2015

MILAN 20/21.11.2015

Women super code lab: an amazing opportunity for all the coders to improve their programming skills in a safe and thrilling environment.

Manuela Munaretto - XPeppers

MILAN 20/21.11.2015 - Manuela Munaretto

Agenda

25’: welcome and introduction to the codelab5’: Pair forming35’: Session #110’: retrospective35’: Session #2

60’: lunch break

10’: retrospective5′: Pair forming45’: Session #310’: retrospective

5’: break

35’: final retrospective + Q&A


Our tools

★ Prerequisites★ TDD★ 4 rules of simple design★ Pair Programming



Prerequites: How

1. Prior knowledge of coding2. Laptop3. Development Environment4. Test Libraries


Prerequites: Why★ Improve your skills★ Intensive practice event★ Away from the pressures





Test Driven Development: How

1. Add a little test2. Run all tests and fail3. Make a little change4. Run the tests and succeed5. Refactor to remove duplication


Test Driven Development: Why★ What needs to be done ★ Requirements are nailed down★ Immediate feedback★ System design★ Only the features you wanted



4 rules of simple design: How

1. Passes all the tests2. Expresses every idea that we need to express3. Contains no duplication4. Minimal method, classes and modules


4 rules of simple design: Why

★ High cohesion and loose coupling★ Compact ★ Modular code★ Expressing all the important ideas of the system



Pair Programming: How

1. Sit side by side in front of the monitor2. Switch roles often 3. Switch pair daily4. Appropriate workspace layout5. Take a break from working together6. Pair programming is chatting


Pair Programming: Why

★ It’s funny ★ Less frustration★ More focused★ Less bugs ★ Higher quality fighting poor practices★ Continuous code review★ Collective code ownership



String Calculator: a kata

Kata is often described as a set sequence of karate moves organized into a pre-arranged fight against imaginary opponents.

A system of individual training exercises in karate and other martial arts.


String Calculator: Why

The following is a TDD Kata- an exercise in coding, refactoring and test-first, that you should apply daily.

Try not to read ahead.

Do one task at a time. The trick is to learn to work incrementally.

Make sure you only test for correct inputs. There is no need to test for invalid inputs for this kata


String Calculator: Step 1

Create a simple String calculator with a method int Add(string numbers)1. The method can take 0, 1 or 2 numbers, and will

return their sum (for an empty string it will return 0) for example “” or “1” or “1,2”

2. Start with the simplest test case of an empty string and move to one and two numbers

3. Remember to solve things as simply as possible so that you force yourself to write tests you did not think about

4. Remember to refactor after each passing test



Allow the Add method to handle an unknown amount of numbers



Allow the Add method to handle new lines between numbers (instead of commas).1. the following input is ok: “1\n2,3” (will equal 6)2. the following input is NOT ok: “1,\n” (not need to

prove it - just clarifying)



Support different delimiters1. to change a delimiter, the beginning of the string will

contain a separate line that looks like this: “//[delimiter]\n[numbers…]” for example “//;\n1;2” should return 3 where the default delimiter is ‘;’ .

2. the first line is optional. All existing scenarios should still be supported



Calling Add with a negative number will throw an exception “negatives not allowed” - and the negative that was passed.

If there are multiple negatives, show all of them in the exception message



Numbers bigger than 1000 should be ignored, so adding 2 + 1001 = 2



Delimiters can be of any length with the following format: “//[delimiter]\n”

for example: “//[***]\n1***2***3”

should return 6



Allow multiple delimiters like this: “//[delim1][delim2]\n”

for example “//[*][%]\n1*2%3”

should return 6



Make sure you can also handle multiple delimiters with length longer than one char


Resources

Extreme Programming: A gentle introductionhttp://www.extremeprogramming.org/

Test-Driven Development: By Example - Kent Beck http://www.amazon.it/dp/0321146530/ref=cm_sw_r_tw_dp_5rgrwb1F002NJ

Cunningham & Cunningham, Inc.http://c2.com/


Resources

String Calculatorhttp://osherove.com/tdd-kata-1/

MILAN 20/21.11.2015

Manuela Munaretto - @[email protected]

XPeppers


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Manuela Munaretto, Gabriele Lana, Filippo Liverani - Women super code lab – Improve your skills with TDD Pair Programming code session | Codemotion Milan 2015