Got units? Bengaluru, 20-22 November 2011
TDDBengaluru, 20-22 November 2011
REDadd a test, it wont pass Bengaluru, 20-22 November 2011
GREENimplement the necessary code to make the test pass Bengaluru, 20-22 November 2011
REFACTOR polish the code Bengaluru, 20-22 November 2011
TDD-ing Dijkstrasshortest path algorithm in PHP Bengaluru, 20-22 November 2011
Bengaluru, 20-22 November 2011
Bengaluru, 20-22 November 2011
Bengaluru, 20-22 November 2011
Bengaluru, 20-22 November 2011
Bengaluru, 20-22 November 2011
Bengaluru, 20-22 November 2011
Bengaluru, 20-22 November 2011
Bengaluru, 20-22 November 2011
Bengaluru, 20-22 November 2011
github.com/odino/osidays Bengaluru, 20-22 November 2011
git checkout $stepBengaluru, 20-22 November 2011
Step 0/1● create the directory structure● add Symfony2 classloader as submodule● init and update submodule● (optional) cre...
Step 2● write the test with the smallest amount of code you think its necessary Bengaluru, 20-22 Novembe...
Step 3● add the Vertex class● add the Graph class● add an empty solve() method for the algorithm class Beng...
Step 4● implement the solve method Bengaluru, 20-22 November 2011
Step 5● added all the methods needed by the Dijkstra::solve()● need to implement Graph::calculatePotentials() ...
Step 6● a test is added for the Graph class Bengaluru, 20-22 November 2011
Step 7● calculatePotentials() is tested● half of our test-suite passes● switch back to the Dijkstras test ...
Step 8● minor tweaks to make all the tests pass Bengaluru, 20-22 November 2011
Step 9● potentials are assigned in the Graph class but they should belong to the algorithm, what about refactoring the c...
Step 10● since we like to be OO, we can connect vertices through objects, and not arrays anymore Bengalu...
Step 11● we now need to fix the code which uses vertices connections as arrays Bengaluru, 20-22 November ...
Step 12● the library seems pretty complete● PHPDoc is added Bengaluru, 20-22 November 2011
Step 13● Oooops, we forgot to test a scenario: in Dijkstras algorithm we need vertices connected by positive distance● a...
Step 14● implementation Bengaluru, 20-22 November 2011
Step 15● enter Mocking objects Bengaluru, 20-22 November 2011
Step 16● Dijkstra::getGraph() seems to be useless so we probably dont need any Graph class Bengaluru, 20-2...
Step 17● removed Graph class Bengaluru, 20-22 November 2011
Step 18● some tests rely on it, so we need to eliminate old references to Graph Bengaluru, 20-22 November...
Step 19● enter Data Providers Bengaluru, 20-22 November 2011
Step 20● what about calculating the path between not-connected vertices? It should return null, so code is refactored ...
Step 21● Dijkstra::solve() seems to do too much things, so we split the method● first demand potentials calculation● seco...
Alessandro Nadalin Bengaluru, 20-22 November 2011
odino.orgBengaluru, 20-22 November 2011
Bengaluru, 20-22 November 2011
@_odino_ #osidaysBengaluru, 20-22 November 2011
REST in peace: tomorrow, 12.45 Bengaluru, 20-22 November 2011
Thank YOU! @_odino_ Bengaluru, 20-22 November 2011
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Got units? @ Osidays 2011 India 11-20-2011

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A TDD tutorial on implementing Dijkstra's shortest path algorithm in PHP with test-driven development and PHPUnit.

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Got units? @ Osidays 2011 India 11-20-2011

  1. 1. Got units? Bengaluru, 20-22 November 2011
  2. 2. TDDBengaluru, 20-22 November 2011
  3. 3. REDadd a test, it wont pass Bengaluru, 20-22 November 2011
  4. 4. GREENimplement the necessary code to make the test pass Bengaluru, 20-22 November 2011
  5. 5. REFACTOR polish the code Bengaluru, 20-22 November 2011
  6. 6. TDD-ing Dijkstrasshortest path algorithm in PHP Bengaluru, 20-22 November 2011
  7. 7. Bengaluru, 20-22 November 2011
  8. 8. Bengaluru, 20-22 November 2011
  9. 9. Bengaluru, 20-22 November 2011
  10. 10. Bengaluru, 20-22 November 2011
  11. 11. Bengaluru, 20-22 November 2011
  12. 12. Bengaluru, 20-22 November 2011
  13. 13. Bengaluru, 20-22 November 2011
  14. 14. Bengaluru, 20-22 November 2011
  15. 15. Bengaluru, 20-22 November 2011
  16. 16. github.com/odino/osidays Bengaluru, 20-22 November 2011
  17. 17. git checkout $stepBengaluru, 20-22 November 2011
  18. 18. Step 0/1● create the directory structure● add Symfony2 classloader as submodule● init and update submodule● (optional) create an empty class Bengaluru, 20-22 November 2011
  19. 19. Step 2● write the test with the smallest amount of code you think its necessary Bengaluru, 20-22 November 2011
  20. 20. Step 3● add the Vertex class● add the Graph class● add an empty solve() method for the algorithm class Bengaluru, 20-22 November 2011
  21. 21. Step 4● implement the solve method Bengaluru, 20-22 November 2011
  22. 22. Step 5● added all the methods needed by the Dijkstra::solve()● need to implement Graph::calculatePotentials() Bengaluru, 20-22 November 2011
  23. 23. Step 6● a test is added for the Graph class Bengaluru, 20-22 November 2011
  24. 24. Step 7● calculatePotentials() is tested● half of our test-suite passes● switch back to the Dijkstras test Bengaluru, 20-22 November 2011
  25. 25. Step 8● minor tweaks to make all the tests pass Bengaluru, 20-22 November 2011
  26. 26. Step 9● potentials are assigned in the Graph class but they should belong to the algorithm, what about refactoring the code?● since we move the only tested method of Graph into Dijkstras class, we can delete the GraphTest Bengaluru, 20-22 November 2011
  27. 27. Step 10● since we like to be OO, we can connect vertices through objects, and not arrays anymore Bengaluru, 20-22 November 2011
  28. 28. Step 11● we now need to fix the code which uses vertices connections as arrays Bengaluru, 20-22 November 2011
  29. 29. Step 12● the library seems pretty complete● PHPDoc is added Bengaluru, 20-22 November 2011
  30. 30. Step 13● Oooops, we forgot to test a scenario: in Dijkstras algorithm we need vertices connected by positive distance● a test is added, verifying an exception is raised through annotations Bengaluru, 20-22 November 2011
  31. 31. Step 14● implementation Bengaluru, 20-22 November 2011
  32. 32. Step 15● enter Mocking objects Bengaluru, 20-22 November 2011
  33. 33. Step 16● Dijkstra::getGraph() seems to be useless so we probably dont need any Graph class Bengaluru, 20-22 November 2011
  34. 34. Step 17● removed Graph class Bengaluru, 20-22 November 2011
  35. 35. Step 18● some tests rely on it, so we need to eliminate old references to Graph Bengaluru, 20-22 November 2011
  36. 36. Step 19● enter Data Providers Bengaluru, 20-22 November 2011
  37. 37. Step 20● what about calculating the path between not-connected vertices? It should return null, so code is refactored Bengaluru, 20-22 November 2011
  38. 38. Step 21● Dijkstra::solve() seems to do too much things, so we split the method● first demand potentials calculation● second demand path finding● third demand raising the negative-potentials exception● enter phploc● enter code-coverage Bengaluru, 20-22 November 2011
  39. 39. Alessandro Nadalin Bengaluru, 20-22 November 2011
  40. 40. odino.orgBengaluru, 20-22 November 2011
  41. 41. Bengaluru, 20-22 November 2011
  42. 42. @_odino_ #osidaysBengaluru, 20-22 November 2011
  43. 43. REST in peace: tomorrow, 12.45 Bengaluru, 20-22 November 2011
  44. 44. Thank YOU! @_odino_ Bengaluru, 20-22 November 2011

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