Add unit tests for optimistic sell update decrementing holdings quantity correctly

[Chucks1093]

Summary

The sell flow should apply an optimistic update to the holdings cache immediately on submission, decrementing the held quantity. Unit tests should confirm the decrement is applied correctly, that the entry is removed when the result reaches zero, and that the update is rolled back on failure.

Scope

• Seed the cache with a holding of 3 keys for a creator
• Submit a sell of 2 keys and assert the cache shows 1 key remaining
• Submit a sell of 1 key (the last) and assert the holding entry is removed from the cache
• Simulate a failure on the second sell and assert the cache is restored to 2 keys

Acceptance Criteria

• Cache decremented by sold quantity on submission
• Entry removed from cache when quantity reaches zero
• Cache restored to pre-sell snapshot on failure
• Rollback uses the snapshot, not a re-fetch

ETA: 12 hours

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Coordinate on Telegram

[bashir1738]

@bashir1738 has applied to work on this issue as part of the Stellar Wave Program's 7th wave.

gm i will like to work on this issue

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[Oluwasuyi-Oluwatimilehin-Daniel]

@Oluwasuyi-Oluwatimilehin-Daniel has applied to work on this issue as part of the Stellar Wave Program's 7th wave.

please assign me

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[Rafiat30]

@Rafiat30 has applied to work on this issue as part of the Stellar Wave Program's 7th wave.

can i work on this

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[Abdullahi130]

@Abdullahi130 has applied to work on this issue as part of the Stellar Wave Program's 7th wave.

I would like to apply to this job,I will surely meet this project criteria and implement it correctly

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[OpensrcLord]

@OpensrcLord has applied to work on this issue as part of the Stellar Wave Program's 7th wave.

Hello @maintainer, I understand the expected outcome and would love to work on this. I'll provide a solution that satisfies the acceptance criteria.

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[drips-wave]

Congratulations, @Rafiat30! 🎉 Your application was accepted by the repo's maintainers, and the issue is due on July 30, 2026.

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