Export themes

[alexjeffburke]

This PR alters unexpected-dom to export the supporting styles corresponding to its exported assertions and types.

The rationale behind the implementation is to work within the following constraints:

• magicpen-prism is a magicpen plugin as well as an Unexpected plugin and should continue to function that way
  • -> it is the unexpected-dom that provides these facilities to its parent, therefore exporting all pre-requisites for its operation should remain its responsibility
• Unexpected currently manages children, and is the only component aware of "child" instances
  • -> for this reason, exportTheme() should remain a concept for Unexpected only

This PR depends on:

• exportTheme unexpected#681
• exportTheme magicpen-prism#5

[coveralls]

Pull Request Test Coverage Report for Build 1309

• 1 of 1 (100.0%) changed or added relevant line in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 93.502%

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Totals
Change from base Build 1301:	0.0%
Covered Lines:	690
Relevant Lines:	720

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💛 - Coveralls

[papandreou]

Hmm, this is a bit awkward. I wonder if we should make theme-exporting a magicpen feature?

[alexjeffburke]

@papandreou hm I’m not sure it makes sense for magicpen - it doesn’t have a concept of children, so we’d end up with it having an exportTheme method being synonymous with installTheme which Unexpected core would overwrite to treat specially.

I tried to note down the constraints that played in here in the description, but to summarise exporting is an Unexpected only concept and my sense is it should remain so. I’d also note exportStyle already works this way, so it seemed consistent.

[papandreou]

But it's nasty if every plugin that uses magicpen-prism internally has to do this.

[alexjeffburke]

@papandreou I see what you're getting at - may have a suggestion.

[alexjeffburke]

@papandreou I had a small brainwave that might allow us to address this with less nastiness in each assertion - let me know what you think of: https://github.com/unexpectedjs/unexpected-dom/pull/307/files#diff-1fdf421c05c1140f6d71444ea2b27638R270

Basically, I propose an additional exportPlugin() method - what this does, is given any plugin it causes all the bits of it to be exported. Implenentation in core is here: unexpectedjs/unexpected@fac75c7

[alexjeffburke]

Superseded by #309.