test: Add importdescriptors rpc error test coverage #35630

In addition to #35179 (already merged) this adds more missing test coverage that was detected while rebasing #34861.

The three tests added checks:

• Locked wallet throws because of being locked if giving an empty importdescriptors request.
• Invalid or missing timestamp throws as a top level RPC error and not a per-item error.
• The order of the requests and the response is the same, even if failing or succeeding.

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Code Coverage & Benchmarks

For details see: https://corecheck.dev/bitcoin/bitcoin/pulls/35630.

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Why is it desirable to enforce the order in which these errors are enforced?

Why is it desirable to enforce the order in which these errors are enforced?

+1

Why is it desirable to enforce the order in which these errors are enforced?

Because the importdescriptors RPC response is an array. Not a json with key-value elements that can be used to match requests and responses. If the order is not kept if an import fail you cannot know which descriptor is the one that failed.

@polespinasa That makes sense. What I mean is e.g. in https://github.com/bitcoin/bitcoin/pull/35630/changes/2d536455829b904138c8853d9aed636916373e94 it seems that the test is checking that even when the importdescriptors call is erroneous because it's passed an empty list of descriptors, that the error is for being locked and not for being an empty list of descriptors. I guess what I'm asking is why does it matter to enforce which error gets checked for first, that seems like an implementation detail, but maybe I have misunderstood what is being tested for there.