Add support and tests for capability specification via provides

[pipex]

This updates the satisfiesChildContract and getNotSatisfiedRequirements functions to check for capabilities defined via provides on the current context. This PR is just surfacing some functionality that was already partially there but never tested.

Change-type: minor
Depends-on: #79

[Page-]

I'm less confident on this combination but it should work (I may have done the conversion incorrectly, but the conversion into a single every should be possible)

Suggested change

	const disjuncts = filter(requirement.raw.data.getAll(), (disjunct) => {
	return shouldEvaluateType(disjunct.raw.data.type);
	});
	// (3.2) An empty disjuction means that this particular
	// requirement is fulfilled, so we can carry on.
	// A disjunction naturally contains a list of further
	// requirements we need to check for. If at least one
	// of the members is fulfilled, we can proceed with
	// next requirement.
	if (disjuncts.length === 0 || some(disjuncts, hasMatch)) {
	return true;
	}
	// (3.2) An empty disjuction means that this particular
	// requirement is fulfilled, so we can carry on.
	// A disjunction naturally contains a list of further
	// requirements we need to check for. If at least one
	// of the members is fulfilled, we can proceed with
	// next requirement.
	if (every(requirement.raw.data.getAll(), (disjunct) => {
	return !shouldEvaluateType(disjunct.raw.data.type) || !hasMatch(disjunct)
	})) {
	return true;
	}

[pipex]

This doesn't work unfortunately, in order for the requirement to be accepted we need either:

• there are no requirements to evaluate
• if there are requirements to evaluate, there is at least one match

The closest thing would be

if (
	every(requirement.raw.data.getAll(), (disjunct) => {
		return (
			!shouldEvaluateType(disjunct.raw.data.type) || hasMatch(disjunct)
		);
	})
) {
	return true;
}

however this is not the same, because if shouldEvaluateType(disjunct.raw.data.type) is always true, this is equivalent to writing

if (
	every(requirement.raw.data.getAll(), (disjunct) => {
		return hasMatch(disjunct);
	})
) {
	return true;
}

which is the opposite of what we want

I'm not sure there is an equivalent using a single some/every

[Page-]

Yeah, I think the problem is we need every(disjuncts, !shouldEvaluateType) || some(disjuncts, shouldEvaluateType && hasMatch) and those can't be combined so what we currently have is the best we can manage with functional. However it can be done via a for-loop with return to short-circuit the some case but keeping the every case requiring an entire loop:

Suggested change

	const disjuncts = filter(requirement.raw.data.getAll(), (disjunct) => {
	return shouldEvaluateType(disjunct.raw.data.type);
	});
	// (3.2) An empty disjuction means that this particular
	// requirement is fulfilled, so we can carry on.
	// A disjunction naturally contains a list of further
	// requirements we need to check for. If at least one
	// of the members is fulfilled, we can proceed with
	// next requirement.
	if (disjuncts.length === 0 || some(disjuncts, hasMatch)) {
	return true;
	}
	// (3.2) An empty disjuction means that this particular
	// requirement is fulfilled, so we can carry on.
	// A disjunction naturally contains a list of further
	// requirements we need to check for. If at least one
	// of the members is fulfilled, we can proceed with
	// next requirement.
	let noneToEvaluate = true;
	for (const disjunct of (requirement.raw.data.getAll()) {
	if (shouldEvaluateType(disjunct.raw.data.type)) {
	noneToEvaluate = false
	if (hasMatch(disjunct)) {
	return true;
	}
	}
	}
	return noneToEvaluate;

Fwiw I don't think this is worth it unless it's a performance bottleneck but since I dug into how to do it I thought I'd share

[pipex]

It does sacrifice a bit of readability, I suspect at some point we'll need to work on the efficiency of some of the operations at which point we can review. Thank you for looking into it!