Test-Driven Development

Introduction to Test-Driven Development, with examples in JavaScript.

Transcript

1. Test-Driven Development turn development on its head Aaron Nordyke Sr. Software Engineer Innovations Development
2. If I were being completely honest, there’s been a consistent pattern in my projects.
3. Stupid Bugs Low Test Coverage Dirty Code Fear Of Breaking Anything Zero Unit Tests
4. Dirty Code
5. function fillXigrisRelative(){ try { var at = _g("relativeTable"); //var docfrag = document.createDocumentFragment(); //INR > 3.0 - PTT > 40 sec //INR ea = getEvents("sep_inr_ec", SEPSISREPLY); for (i = 0; i < ea.length; i++) { for (j = 0; j < SEPSISREPLY.VALUES[ea[i]].EVENTS.length; j++) { event_dt = SEPSISREPLY.VALUES[ea[i]].EVENTS[j].EVENTDTDISP; disp = SEPSISREPLY.VALUES[ea[i]].EVENTS[j].EVENT_DISP; rslt = SEPSISREPLY.VALUES[ea[i]].EVENTS[j].EVENT_RESULT; xigrisNotify(_g("inrptt_notify"), [disp, rslt, event_dt]); if (SEPSISREPLY.VALUES[ea[i]].EVENTS[j].RSLTVAL > 3.0) { _g("rel_inrptt_form").ynu[0].checked = true; } } } //PTT ea = getEvents("sep_ptt_ec", SEPSISREPLY); for (i = 0; i < ea.length; i++) { for (j = 0; j < SEPSISREPLY.VALUES[ea[i]].EVENTS.length; j++) { event_dt = SEPSISREPLY.VALUES[ea[i]].EVENTS[j].EVENTDTDISP; disp = SEPSISREPLY.VALUES[ea[i]].EVENTS[j].EVENT_DISP; rslt = SEPSISREPLY.VALUES[ea[i]].EVENTS[j].EVENT_RESULT; xigrisNotify(_g("inrptt_notify"), [disp, rslt, event_dt]); if (SEPSISREPLY.VALUES[ea[i]].EVENTS[j].RSLTVAL > 40) { _g("rel_inrptt_form").ynu[0].checked = true; } } } … Dirty Code Big functions
6. //Platelet Count ea = getEvents("sep_plt_ec", SEPSISREPLY); for (i = 0; i < ea.length; i++) { for (j = 0; j < SEPSISREPLY.VALUES[ea[i]].EVENTS.length; j++) { event_dt = SEPSISREPLY.VALUES[ea[i]].EVENTS[j].EVENTDTDISP; disp = SEPSISREPLY.VALUES[ea[i]].EVENTS[j].EVENT_DISP; rslt = SEPSISREPLY.VALUES[ea[i]].EVENTS[j].EVENT_RESULT; xigrisNotify(_g("platelet_notify"), [disp, rslt, event_dt]); if (SEPSISREPLY.VALUES[ea[i]].EVENTS[j].RSLTVAL < 30000) { _g("rel_platelet_form").ynu[0].checked = true; } } } //Gastro-intestinal bleed ea = getEvents("sep_gi_hem_dx", SEPSISREPLY); for (i = 0; i < ea.length; i++) { disp = SEPSISREPLY.VALUES[ea[i]].VALEVENTFTX; rslt = SEPSISREPLY.VALUES[ea[i]].VALEVENTNOMDISP; event_dt = SEPSISREPLY.VALUES[ea[i]].VALEVENTMPVAL; xigrisNotify(_g("gastro_notify"), [disp,rslt,event_dt]); //_g("rel_gastro_form").ynu[0].checked = true; } //Thrombolytic therapy ea = getEvents("sep_thrombolytics_adm", SEPSISREPLY); for (i = 0; i < ea.length; i++) { for (j = 0; j < SEPSISREPLY.VALUES[ea[i]].EVENTS.length; j++) { event_dt = SEPSISREPLY.VALUES[ea[i]].EVENTS[j].EVENTDTDISP; disp = SEPSISREPLY.VALUES[ea[i]].EVENTS[j].EVENT_DISP; rslt = SEPSISREPLY.VALUES[ea[i]].EVENTS[j].EVENT_RESULT; xigrisNotify(_g("thrombo_notify"), [disp, rslt, "Dose Given: " + event_dt]); _g("rel_thrombo_form").ynu[0].checked = true; } } … …that keep going Dirty Code
7. //Oral anticoagulants or... ea = getEvents("sep_oral_anticoag_adm", SEPSISREPLY); for (i = 0; i < ea.length; i++) { for (j = 0; j < SEPSISREPLY.VALUES[ea[i]].EVENTS.length; j++) { event_dt = SEPSISREPLY.VALUES[ea[i]].EVENTS[j].EVENTDTDISP; disp = SEPSISREPLY.VALUES[ea[i]].EVENTS[j].EVENT_DISP; rslt = SEPSISREPLY.VALUES[ea[i]].EVENTS[j].EVENT_RESULT; xigrisNotify(_g("antiglyco_notify"), [disp, rslt, "Dose Given: " + event_dt]); _g("rel_antiglyco_form").ynu[0].checked = true; } } //...glycoprotein ea = getEvents("sep_glyco_plt_inh_adm", SEPSISREPLY); for (i = 0; i < ea.length; i++) { for (j = 0; j < SEPSISREPLY.VALUES[ea[i]].EVENTS.length; j++) { event_dt = SEPSISREPLY.VALUES[ea[i]].EVENTS[j].EVENTDTDISP; disp = SEPSISREPLY.VALUES[ea[i]].EVENTS[j].EVENT_DISP; rslt = SEPSISREPLY.VALUES[ea[i]].EVENTS[j].EVENT_RESULT; xigrisNotify(_g("antiglyco_notify"), [disp, rslt, "Dose Given: " + event_dt]); _g("rel_antiglyco_form").ynu[0].checked = true; } } //Aspirin or... ea = getEvents("sep_aspirin_adm", SEPSISREPLY); for (i = 0; i < ea.length; i++) { for (j = 0; j < SEPSISREPLY.VALUES[ea[i]].EVENTS.length; j++) { event_dt = SEPSISREPLY.VALUES[ea[i]].EVENTS[j].EVENTDTDISP; disp = SEPSISREPLY.VALUES[ea[i]].EVENTS[j].EVENT_DISP; rslt = SEPSISREPLY.VALUES[ea[i]].EVENTS[j].EVENT_RESULT; xigrisNotify(_g("aspirin_notify"), [disp, rslt, "Dose Given: " + event_dt]); //TODO - less than 24 hours if (SEPSISREPLY.VALUES[ea[i]].EVENTS[j].RSLTVAL > 650) { _g("rel_aspirin_form").ynu[0].checked = true; …and going Dirty Code
8. } } } //...other platelet inhibitor ea = getEvents("sep_plt_adm", SEPSISREPLY); for (i = 0; i < ea.length; i++) { for (j = 0; j < SEPSISREPLY.VALUES[ea[i]].EVENTS.length; j++) { event_dt = SEPSISREPLY.VALUES[ea[i]].EVENTS[j].EVENTDTDISP; disp = SEPSISREPLY.VALUES[ea[i]].EVENTS[j].EVENT_DISP; rslt = SEPSISREPLY.VALUES[ea[i]].EVENTS[j].EVENT_RESULT; xigrisNotify(_g("aspirin_notify"), ["Active Order", disp]); _g("rel_aspirin_form").ynu[0].checked = true; } } //Ischemic Stroke ea = getEvents("sep_ischemic_stk_dx", SEPSISREPLY); for (i = 0; i < ea.length; i++) { disp = SEPSISREPLY.VALUES[ea[i]].VALEVENTFTX; rslt = SEPSISREPLY.VALUES[ea[i]].VALEVENTNOMDISP; event_dt = SEPSISREPLY.VALUES[ea[i]].VALEVENTMPVAL; xigrisNotify(_g("stroke_notify"), [disp,rslt,event_dt]); //_g("rel_stroke_form").ynu[0].checked = true; } //Intracranial Arteriovenous Malformation or aneurysm ea = getEvents("sep_aneurysm_dx", SEPSISREPLY); for (i = 0; i < ea.length; i++) { disp = SEPSISREPLY.VALUES[ea[i]].VALEVENTFTX; rslt = SEPSISREPLY.VALUES[ea[i]].VALEVENTNOMDISP; event_dt = SEPSISREPLY.VALUES[ea[i]].VALEVENTMPVAL; xigrisNotify(_g("aneurysm_notify"), [disp,rslt,event_dt]); _g("rel_aneurysm_form").ynu[0].checked = true; } …and going Dirty Code
9. //Chronic Severe Hepatic Disease //...Hepatic ea = getEvents("sep_hepatic_dis_dx", SEPSISREPLY); for (i = 0; i < ea.length; i++) { disp = SEPSISREPLY.VALUES[ea[i]].VALEVENTFTX; rslt = SEPSISREPLY.VALUES[ea[i]].VALEVENTNOMDISP; event_dt = SEPSISREPLY.VALUES[ea[i]].VALEVENTMPVAL; xigrisNotify(_g("hepatic_notify"), [disp,rslt,event_dt]); _g("rel_hepatic_form").ynu[0].checked = true; } //...ALT > 100 ea = getEvents("sep_alt_ec", SEPSISREPLY); for (i = 0; i < ea.length; i++) { for (j = 0; j < SEPSISREPLY.VALUES[ea[i]].EVENTS.length; j++) { event_dt = SEPSISREPLY.VALUES[ea[i]].EVENTS[j].EVENTDTDISP; disp = SEPSISREPLY.VALUES[ea[i]].EVENTS[j].EVENT_DISP; rslt = SEPSISREPLY.VALUES[ea[i]].EVENTS[j].EVENT_RESULT; xigrisNotify(_g("hepatic_notify"), [disp, rslt, event_dt]); if (SEPSISREPLY.VALUES[ea[i]].EVENTS[j].RSLTVAL > 100) { _g("rel_hepatic_form").ynu[0].checked = true; } } } //...AST > 100 ea = getEvents("sep_ast_ec", SEPSISREPLY); for (i = 0; i < ea.length; i++) { for (j = 0; j < SEPSISREPLY.VALUES[ea[i]].EVENTS.length; j++) { event_dt = SEPSISREPLY.VALUES[ea[i]].EVENTS[j].EVENTDTDISP; disp = SEPSISREPLY.VALUES[ea[i]].EVENTS[j].EVENT_DISP; rslt = SEPSISREPLY.VALUES[ea[i]].EVENTS[j].EVENT_RESULT; xigrisNotify(_g("hepatic_notify"), [disp, rslt, event_dt]); …and going Dirty Code
10. if (SEPSISREPLY.VALUES[ea[i]].EVENTS[j].RSLTVAL > 100) { _g("rel_hepatic_form").ynu[0].checked = true; } } } //...AST ea = getEvents("sep_bilirubin_ec", SEPSISREPLY); for (i = 0; i < ea.length; i++) { for (j = 0; j < SEPSISREPLY.VALUES[ea[i]].EVENTS.length; j++) { event_dt = SEPSISREPLY.VALUES[ea[i]].EVENTS[j].EVENTDTDISP; disp = SEPSISREPLY.VALUES[ea[i]].EVENTS[j].EVENT_DISP; rslt = SEPSISREPLY.VALUES[ea[i]].EVENTS[j].EVENT_RESULT; xigrisNotify(_g("hepatic_notify"), [disp, rslt, event_dt]); if (SEPSISREPLY.VALUES[ea[i]].EVENTS[j].RSLTVAL > 2) { _g("rel_hepatic_form").ynu[0].checked = true; } } } //Pregnant or Breastfeeding ea = getEvents("sep_pregnant_ec", SEPSISREPLY); for (i = 0; i < ea.length; i++) { for (j = 0; j < SEPSISREPLY.VALUES[ea[i]].EVENTS.length; j++) { event_dt = SEPSISREPLY.VALUES[ea[i]].EVENTS[j].EVENTDTDISP; disp = SEPSISREPLY.VALUES[ea[i]].EVENTS[j].EVENT_DISP; rslt = SEPSISREPLY.VALUES[ea[i]].EVENTS[j].EVENT_RESULT; xigrisNotify(_g("pregnant_notify"), [disp, rslt, event_dt]); _g("rel_pregnant_form").ynu[0].checked = true; } } ea = getEvents("sep_breastfeeding_ec", SEPSISREPLY); for (i = 0; i < ea.length; i++) { …and going Dirty Code
11. for (j = 0; j < SEPSISREPLY.VALUES[ea[i]].EVENTS.length; j++) { event_dt = SEPSISREPLY.VALUES[ea[i]].EVENTS[j].EVENTDTDISP; disp = SEPSISREPLY.VALUES[ea[i]].EVENTS[j].EVENT_DISP; rslt = SEPSISREPLY.VALUES[ea[i]].EVENTS[j].EVENT_RESULT; xigrisNotify(_g("pregnant_notify"), [disp, rslt, event_dt]); _g("rel_pregnant_form").ynu[0].checked = true; } } //check with handler xigrisRelativeHandler(); } catch (e) { errorHandler(e, "fillXigrisRelative()"); } } …and going Dirty Code
12. Dirty Code A function should do one thing. Big functions “One thing. Just one thing. You stick to that and the rest don't mean sh*t.” Curly, City Slickers
13. High coupling Dirty Code
14. Dirty Code Zero Unit Tests
15. Zero Unit Tests Dirty Code is hard to test
16. Ease of Unit Testing Function Size Zero Unit Tests
17. Zero Unit Tests Coupling Ease of Unit Testing
18. Zero Unit Tests Number of things the function does Ease of Unit Testing
19. Low Test Coverage Dirty Code Zero Unit Tests
20. Low Test Coverage I relied on a little helper who was never meant to have so much responsibility.
21. Low Test Coverage Functional Tests King of the Black Boxes
22. Low Test Coverage Functional Testing has its place A-Bomb Testing, Nevada Test Site, 1955
23. Stupid Bugs Low Test Coverage Dirty Code Zero Unit Tests
24. Stupid Bugs “How in the hell did I miss that one?” - Me, after every defect
25. Stupid Bugs Low Test Coverage Dirty Code Fear Of Breaking Anything Zero Unit Tests
26. Fear of Breaking Anything
27. code write Conventional Development
28. Conventional Development code test
29. Conventional Development What if we reversed it? code write code test
30. Conventional Development What if we reversed it? code test code write (WTF?)
31. Test-Driven Development turn development on its head
32. Test-Driven Development “Red, Green, Refactor”
33. Red Green Refactor Test-Driven Development Write a test that fails Make the test pass 1 2 Clean up code 3
34. a (very) trivial example
35. 1. Write a test that fails 1. Write one unit test 2. Run the test and verify the failure addNumber_test.js
36. 2. Make the test pass 1. Write just enough code to make failing test pass. 2. Run the test and verify the success addNumber_test.js addNumber.js
37. 3. Clean up code If able, clean up Code and Unit Tests “Leave the campground cleaner than you found it.” Boy Scouts of America
38. 1. Write a test that fails 1. Write one unit test 2. Run the test and verify the failure addNumber_test.js (Round 2)
39. 2. Make the test pass 1. Write just enough code to make failing test pass. 2. Run the test and verify the success addNumber.js addNumber_test.js (Round 2)
40. 3. Clean up code It’s tough to clean code this simple, so we’re done. addNumber.js addNumber_test.js (Round 2)
41. Stupid Bugs Low Test Coverage Dirty Code Fear Of Breaking Anything Zero Unit Tests
42. Stupid Bugs (but a whole lot less of them) High Test Coverage Clean Code No Fear Of Breaking Anything Lotsa Unit Tests
43. Clean Code smaller functions Having to test a little code at a time forced me to write with lower coupling that did one thing.
44. Lotsa Unit Tests They help me sleep at night
45. High Test Coverage The code follows the tests. It makes sense that test coverage would be high.
46. High Test Coverage I no longer have to rely on the functional testers to tell me my code works. I know it works. For my F5 tells me so.
47. No fear of breaking anything This one’s my favorite, because it means I can refactor mercilessly. Every time I make a code change, I run the tests. They tell me immediately and loudly if I broke anything.
48. No fear of breaking anything Like Patrick Bateman in American Psycho, I laugh maniacally while I carve up bodies of code.
49. Other Reasons that TDD Rules Unit Tests are Documentation
50. Other Reasons that TDD Rules “The act of writing a unit test is more an act of design than of verification. It is also more an act of documentation than of verification. The act of writing a unit test closes a remarkable number of feedback loops, the least of which is the one pertaining to verification of function.” Robert “Uncle Bob” Martin Agile Software Development Closes the Feedback Loop You know code works after 30 seconds, not 10 minutes. ( )
51. It can be quite a struggle at first. Downright painful.
52. No code until you write your tests!
54. Not a silver bullet
55. Questions?