Karumi Dojo - Kata String Calculator

Slides used during the Karumi Coding Dojo to resolve the string calculator kata.

Transcript

1. Pedro V. Gómez Sánchez - pedro@karumi.com - @pedro_g_s - github.com/pedrovgs Karumi Dojo Pedro Vicente Gómez Sánchez Senior Android Developer at Karumi pedro@karumi.com @pedro_g_s github.com/pedrovgs
2. Pedro V. Gómez Sánchez - pedro@karumi.com - @pedro_g_s - github.com/pedrovgs
3. Pedro V. Gómez Sánchez - pedro@karumi.com - @pedro_g_s - github.com/pedrovgs Irene Herranz Managing Director Alberto Gragera Technical Director Jorge Barroso Android Expert Davide Mendolia Full Stack Engineer
4. Pedro V. Gómez Sánchez - pedro@karumi.com - @pedro_g_s - github.com/pedrovgs
5. Pedro V. Gómez Sánchez - pedro@karumi.com - @pedro_g_s - github.com/pedrovgs Karumi Dojo • We are here to practice and learn. • This is a bullshit free environment. • This exercise meant to be collaborative, not competitive. • Try to open your mind to new concepts.
6. Pedro V. Gómez Sánchez - pedro@karumi.com - @pedro_g_s - github.com/pedrovgs Karumi Dojo • We are here to practice Test-Driven Development. • TDD is a software development process, not a dogma. • We are going to practice pair programming. • Keep always in mind the TDD Cycle.
7. Pedro V. Gómez Sánchez - pedro@karumi.com - @pedro_g_s - github.com/pedrovgs Rules: • Write enough test code so that to get a single test failure. • Write enough production code to get all your tests to pass. • Refactor until the code is Simple/Clean.
8. Pedro V. Gómez Sánchez - pedro@karumi.com - @pedro_g_s - github.com/pedrovgs Rules: The TDD Cycle RED GREEN REFACTO R 3. Simplify and clean your code. 1. Write a failing test. 2. Make the code work.
9. Pedro V. Gómez Sánchez - pedro@karumi.com - @pedro_g_s - github.com/pedrovgs Sum the number inside string passed as parameter: 1,2,3 = 6 String Calculator public int add(String numbers) { //Put your code here }
10. Pedro V. Gómez Sánchez - pedro@karumi.com - @pedro_g_s - github.com/pedrovgs Business Rule 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”.
11. Pedro V. Gómez Sánchez - pedro@karumi.com - @pedro_g_s - github.com/pedrovgs Business Rule 2 Allow the Add method to handle an unknown amount of numbers.
12. Pedro V. Gómez Sánchez - pedro@karumi.com - @pedro_g_s - github.com/pedrovgs Business Rule 3 Allow the Add method to handle new lines between numbers (instead of commas).
13. Pedro V. Gómez Sánchez - pedro@karumi.com - @pedro_g_s - github.com/pedrovgs Business Rule 4 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
14. Pedro V. Gómez Sánchez - pedro@karumi.com - @pedro_g_s - github.com/pedrovgs Rule 5 If the delimiter used is not “,” or “\n” throw an exception.
15. Pedro V. Gómez Sánchez - pedro@karumi.com - @pedro_g_s - github.com/pedrovgs Tips • Baby steps. • Don’t lose the green. • Choose the language you prefer. • Refactor your code. • Build errors are not failing tests. • Follow the TDD Cycle.
16. Pedro V. Gómez Sánchez - pedro@karumi.com - @pedro_g_s - github.com/pedrovgs http://goo.gl/erofJ5
17. Pedro V. Gómez Sánchez - pedro@karumi.com - @pedro_g_s - github.com/pedrovgs Extra points
18. Pedro V. Gómez Sánchez - pedro@karumi.com - @pedro_g_s - github.com/pedrovgs Extra Rule 1 Numbers bigger than 1000 should be ignored, so adding 2 + 1001 = 2
19. Pedro V. Gómez Sánchez - pedro@karumi.com - @pedro_g_s - github.com/pedrovgs Extra Rule 2 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 three where the default delimiter is ‘;’ . The first line is optional. all existing scenarios should still be supported
20. Pedro V. Gómez Sánchez - pedro@karumi.com - @pedro_g_s - github.com/pedrovgs Extra Rule 3 Allow multiple delimiters like this: “//[delim1][delim2]\n” for example “//[*][%] \n1*2%3” should return 6.