[Testing] sorobanService submit/simulate/decode paths are untested - soroban.service.test.ts only covers isStale

[grantfox-oss]

Telegram (ask questions / claim the issue here first): https://t.me/+DOylgFv1jyJlNzM0

Why this matters

tests/soroban.service.test.ts only asserts isStale. sorobanService.ts has untested logic that handles funds and chain decoding: submitContractCall error branches, getStreamFromChain/getClaimableFromChain decode + null-on-error fallback, topUpStream's KEEPER_SECRET guard, and its own decodeI128/decodeAddress.

Acceptance criteria

• Add unit tests for submitContractCall covering simulation-error and sendTransaction-ERROR paths (mock rpc.Server)
• Add tests for getStreamFromChain/getClaimableFromChain happy path and null-on-decode-failure
• Add tests for decodeI128/decodeAddress including negative i128 and contract addresses
• Cover topUpStream throwing when KEEPER_SECRET_KEY is unset

Files to touch

• backend/tests/soroban.service.test.ts
• backend/src/services/sorobanService.ts

Out of scope

• Live testnet submission tests

[extolkom]

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[Caneryy]

@Caneryy has applied to work on this issue as part of the Stellar Wave Program's 6th wave.

Hello, may I work on this issue?

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

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[grantfox-oss]

🦊 GrantFox — @extolkom has been assigned to this issue!

Next steps:

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[grantfox-oss]

🎉 This issue has been marked as completed on GrantFox!

@extolkom's PR #970 was approved and merged by @ogazboiz.

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