Abort previous run on --watch change.

[benjie]

Currently when a file change is detected the previous test suite continues running and a new one starts in parallel. This can cause issues with the context sharing issue fixed in #1099; but I also suspect it's not the desired behaviour.

This change aborts the current test suite before starting the fresh one.

(An alternative option would be to queue a new test suite run after the current one completes - I am not sure which is the more desirable option; I think running the fresh tests sooner probably wins from the point of view of giving the programmer up to date feedback?)

[azweb76]

Great change. Please accept pull.

[travisjeffery]

@benjie do you have an example of an issue that occurs with this and #1099?

[benjie]

@travisjeffery Sure: https://github.com/benjie/mocha-issue-1100/blob/master/test/test.js

[travisjeffery]

thanks.

that's passing every time for me, which is expected behavior - no?

btw, i agree that queueing makes more sense than running them in parallel, and queuing them makes less sense than starting the new run immediately.

[benjie]

Added a README with instructions; note the behaviour is only exhibited without the #1099 fix (which was merged) so make sure you're using the release version of 1.16.2 (I had to npm install mocha@1.16.2 to reproduce it as I have my fixed version installed globally).

https://github.com/benjie/mocha-issue-1100

I've written the code to do proper queuing as abort() is not synchronous; will push it a little later today.

[benjie]

I've also updated the test repo to have two tests to show how with this latest commit you can trigger a number of watches and it will complete the test that's currently running before moving on and starting the test suite afresh; e.g. running:

for I in `seq 1 10`; do touch test/test.js; sleep 1; done

will result in "1 passing" 5 times followed finally by "2 passing". Other than the lack of output that the test suite was aborted (e.g. "1 passing, 1 aborted") I think this is the desired behaviour. (Note: I've also decreased the delay variable from 10 seconds to 2 seconds in the test repo.)

It would be simple to add a command line option to allow the user to specify that they want the previous test run to complete fully (no runner.abort()) before starting a new one; however I don't think this is desired despite how simple it is. What are your thoughts on this?