convert ansi colour sequences to coloured span tags

[ulfurinn]

Some testing packages (such as goconvey itself) will colour the output with ANSI escape sequences; the web view will display them as, for example, "[32m✔[0m", which gets noisy very quickly. This patch converts them to span tags with colour classes.

This is based on https://github.com/mmalecki/ansispan

[mholt]

Cool, thanks! I'll take a look at this soon. Pretty in over my head right now with things...

[mdwhatcott]

@ulfurinn - I just encountered this kind of output for the first time. Can you share some of your code that produces the output for you?

For me, it happened because I was writing a test from outside the package under test. For example, if the package I was testing was github.com/smartystreets/blah the package I declared in my test files was github.com/smartystreets/blah_test. This caused the goconvey server to NOT use the -json field becuase go list -f '{{.TestImports}}' no longer found the goconvey package in the imports list. I had no idea this could happen and I'm wondering if this is what you are encountering.

[ulfurinn]

This is indeed the case. bitbucket.org/ulfurinn/options is one example.

If package detection is fixed, could this patch still be useful for running tests using other frameworks that produce coloured output?

[mdwhatcott]

Yes, it still could be useful--thanks for contributing.

[mdwhatcott]

Thanks for confirming my suspicions @ulfurinn. I'm glad to finally know the cause.