why_cant_i_test_my_javascript.txt

Why Can't I Test My Javascript

need to split js code into testable units, not spaghetti code.

(most) everything in js is an object.  we should test objects.

don't put logic in the DOM.

DOM is just an object.

Test js the same way we test everything else.  Add structure to js and write it in a testable object-oriented manner.

what should tests do:  ensure value (catching bugs is a side effect of tests)

Two types of value:
  * external value - end user will experience what app promises to do
    * use end-to-end acceptance test 
      * does it meet the external value?
      * do we understand the external value?
  * internal value - easy to change stuff within app w/o headaches
    * acceptance tests != internal quality
    * need isolated unit tests
    * The act of writing test gives feedback on quality of code
    * running a (successful) unit test tells us we haven't broken any object
    * a unit test will NOT tell us if system works together as a whole

Unit tests tell you that you built the system right, while Acceptance/Integration tests tell you that you built the right system.

Acceptance/Integration tests:
  * poke around at UI (as a user would) and verify expected functionality

Unit tests:
  * tests written for devs or development purposes