Writing Faster Django Tests

Transcript

1. WRITING FASTER DJANGO TESTS
2. "Tests are slow so I am disabling it for a while" - Every Developer everywhere # python manage.py test
3. HOW TO WRITE FASTER TESTS non-trivial code bases have test that normally runs in units of seconds ideally your tests should take less then 30 seconds to run, the less the better Developers disable them or not run them because we are not java guys.
4. GOAL <30 seconds
5. HOW 1. Eliminate bottlenecks 2. When can't eliminate - minimize it 3. When can't minimize - mock it (not literally)
6. BOTTLENECKS IN TESTING I/O
7. HOW TO MINIMIZE / ELIMINATE IO Don't test on real database when developing. in your settings.py add i f ' t e s t ' i n s y s . a r g v o r ' t e s t _ c o v e r a g e ' i n s y s . a r g v : # C o v e r s r e g u l a r t e s t i n g a n d d j a n g o - D A T A B A S E S [ ' d e f a u l t ' ] = { ' E N G I N E ' : ' d j a n g o . d b . b a c k e n d s . s q l i t e 3 ' } D A T A B A S E S [ ' t a p 2 ' ] = { ' E N G I N E ' : ' d j a n g o . d b . b a c k e n d s . s q l i t e 3 ' } D A T A B A S E S [ ' u s e r s d b ' ] = { ' E N G I N E ' : ' d j a n g o . d b . b a c k e n d s . s q l i t e 3 ' }
8. USING FASTER DB FOR TESTING SQLITE runs in memory, in last slide we instructed django to use sqlite whenever test are run or use your database's in-memory mode.
9. DISABLE CRYPTOGRAPHY Change order of password hashers it results in a huge(upto 4-5x YMMV) test speed bump. i f ' t e s t ' i n s y s . a r g v : P A S S W O R D _ H A S H E R S = ( ' d j a n g o . c o n t r i b . a u t h . h a s h e r s . S H A 1 P a s s w o r d H a s h e r ' , ' d j a n g o . c o n t r i b . a u t h . h a s h e r s . P B K D F 2 P a s s w o r d H a s h e r ' , ' d j a n g o . c o n t r i b . a u t h . h a s h e r s . P B K D F 2 S H A 1 P a s s w o r d H a s h e r ' , ' d j a n g o . c o n t r i b . a u t h . h a s h e r s . B C r y p t P a s s w o r d H a s h e r ' , ' d j a n g o . c o n t r i b . a u t h . h a s h e r s . M D 5 P a s s w o r d H a s h e r ' , ' d j a n g o . c o n t r i b . a u t h . h a s h e r s . C r y p t P a s s w o r d H a s h e r ' , )
10. MOCK EVERYTHING Mock all the time consuming tasks DB Calls Network requests meetings :)
11. MOCKING DB CALLS Use something like python's own mock library pip install mock part of standard library in python 3 book = Mock(spec=Book)
12. A PRIMER ON MOCKING A simple tutorial for mocking <this is a placeholder slide to be replaced by actual content later>
13. TIPS FOR MOCKING IN DJANGO using partials to modify function calls patching objects <this is a placeholder slide to be replaced by actual content later>
14. MOCKING REQUESTS use builting client when mocking views using responses by dropbox to mock requests library
15. MAKE IT VISIBLE coverage run python manage.py test Make coverage report accessible to your build tools use django-jenkins (for django > 1.6) to generate various reports
16. ACCOUNTABILITY adding deployment hooks to reject builds which decrease tests
17. JENKINS EXAMPLE jenkins example for visually showing coverage
18. GRAPH <show a graph of increasing coverage over time>
19. QUESTIONS?