Single test per file or not?

David Bruant david.bruant at
Wed Jul 27 05:02:06 PDT 2011

[+Rick Waldron, because he had a discussion on this topic with Dave 
Fugate on Twitter iirc]

Le 27/07/2011 13:28, Geoffrey Sneddon a écrit :
> While the current test262 runner makes the assumption that there is 
> only one test per file (see the implementation of 
> ES5Harness.registerTest), the WebWorker-based demo MS showed off a 
> while back allowed multiple tests per file. Seeming both are, as I 
> understand it, by the same group of people, this is an interesting 
> change.
> Is it intended to allow multiple tests per file, or should there be 
> limits to one test per file (and hence only one call to 
> ES5Harness.registerTest)?
This is an interesting topic. Granularity.
I have myself been a bit annoyed once or twice by this issue. Typically, 
I would run the tests, see one failing and trying to see what was wrong. 
I can't remember which, but sometimes, the test was testing several 
things at once and by doing so, it was harder to track down where the 
non-conformance came from. If i recall, a good share of Sputnik imported 
tests tend to do this.

I have not seen a rational or guidelines or rules discussing test 
granularity and I think it should be done. I think that for the purpose 
of a conformance test suite, the ultimate goal of a test should be to be 
able to spot instantaneously where the non-conformance issue comes from.
There are two things that can help out:
1) test description
I have noticed that it wasn't always perfectly accurate. I will report 
bugs on that as i find time.
2) test granularity

You may disagree and i'd be happy to have a discussion on how tests 
should be designed and maybe providing a set of rules/good 

On top of my head, I see one problem which is that some tests have 
dependency and rely on other parts of the spec to be conformant. So a 
failure in a test can be caused by what the test is testing or one of 
its "conformance dependency". I have no idea on how to help out with 
this issue, but i wanted to pointed out in case other had ideas.


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