Testing cron jobs that run script/runner

Rails
1

I’ve got some logic that runs periodically and I want to include that
in my tests.

I guess, the test will need to modify the Time.now(), so that I can
trigger events to happen and also run some code, in the same way
script/runner would do.

Any suggestions?

Thanks,
Amir

2

helzer wrote:

I’ve got some logic that runs periodically and I want to include that
in my tests.

The closer to the cron event you get, the harder the testing is. Which
do
you want to test?

  • the cron system works
  • the cron file calls your function, not something else
  • your function works.

The last one is highest risk, and you can test that out of normal unit
tests. So most crons should let the first two slide.

I guess, the test will need to modify the Time.now(), so that I can
trigger events to happen and also run some code, in the same way
script/runner would do.

I have experienced two general ways to mock the time. One is to mock
Time.now() so it returns some canned number that the time-dependent code
will relate to.

The other way is to set a previous time stamp wisely in the test
fixtures. A
contrived example for an hourly cron:

due_for_a_cron:
id: 42
data: whatever
last_cron: <%= 61.minutes.ago %>

So a test case that uses a :due_for_a_cron fixture record will always
correctly discover that the time is ripe for the next cron event.

I have found the fixture system to be much more robust than mocking
Time. If
you simply must do that, use Mocha.

–
Phlip
http://www.oreilly.com/catalog/9780596510657/