Add comprehensive test coverage for factory contract edge cases

[prodbycorne]

Overview

The factory contract's test.rs is missing tests for several critical paths. The following scenarios are untested and could mask regressions:

Missing Test Cases

initialize

• Double-initialization returns Err(FactoryError::AlreadyInitialized) — not just that it errors, but that the error code matches
• pool_count is exactly 0 immediately after init

transfer_admin

• Non-admin address calling transfer_admin is rejected
• After transfer, old admin can no longer call create_pool
• adm_xfr event emitted with correct (old, new) payload
• New admin can immediately call create_pool

create_pool

• Non-admin calling create_pool is rejected
• Pool addresses are deterministic — same factory + same pool_id always yields the same address
• pool_count increments by 1 for each created pool
• pool_crtd event includes correct asset, daily_rate, min_lock_period payload
• Pool created at ID 0, then ID 1 — get_pool(0) still returns ID 0's data
• Zero daily_rate pool created — pool record stores 0 correctly

get_pool

• pool_id beyond pool_count returns Err(FactoryError::PoolNotFound)
• TTL is bumped on every get_pool call (verify via storage TTL inspection)

pool_wasm_hash

• Returns the exact hash passed at initialization

Setup Note

Use soroban_sdk::testutils::EnvBuilder with register_at to install a mock WASM hash for pool deployment tests.

Acceptance Criteria

• All test cases above implemented in factory/src/test.rs
• Each test uses a descriptive #[test] function name
• No unwrap() in test assertions — use assert_eq! with Ok(...)\ / Err(...)`
• Tests run in < 5 seconds with cargo test

[clintjeff2]

Hello, I have 6 years of experience working on tasks like this and handling similar challenges across backend, frontend, and smart-contract development. I have carefully read and fully understood the task requirements, and I am confident I can deliver a clean, efficient, and well-tested solution promptly. I always ensure high-quality implementation, maintainability, and adherence to best practices.

Pull request in 5 hours.

[grantfox-oss]

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@ProtonsAndElectrons's PR #43 was approved and merged by @prodbycorne.

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