rs-sdk: replace print-based DPNS tests with real assertions, add error paths

[thepastaclaw]

Parent: #11

• C01: DPNS tests with zero assertions (5 test functions use println/emoji instead of assert)
• I02/I03: Identity fetch tests missing assertions and no error paths
• Magic values throughout without traceability to source

Action: Replace println with assertions. Add error path tests for identity/DPNS fetches. Document magic values.

Source: /tmp/test-audit/sdk-wasm-findings.md

[thepastaclaw]

Starting work on this issue. Here's my approach after exploring the test files:

C01 — DPNS println → assert (5 tests):

• dpns_unit_tests.rs: 3 pure unit tests (test_dpns_validation_functions, test_dpns_edge_cases, test_dpns_homograph_safety) — these have expected values already in the code but just print instead of asserting. Will replace all println with assert_eq!/assert!.
• dpns_queries_test.rs: 2 integration tests (test_dpns_queries_from_docs, test_dpns_search_variations) — these are #[ignore] and require network. Will add assertions where possible (assert Ok results, assert non-empty responses) while keeping #[ignore].

I02/I03 — Identity fetch assertions + error paths:

• identity.rs:test_identity_balance_read and test_identity_balance_revision_read — both use tracing::debug! with no assertions. Will add assert!(balance > 0) and assert!(revision >= 1).
• Will add test_identity_read_not_found using the existing UNKNOWN_IDENTITY_ID constant.

Magic values:

• UNIQUE_KEY_HASH in identity.rs — needs source documentation
• TEST_IDENTITY_ID and hardcoded testnet IP in dpns_queries_test.rs — need documentation
• generated_data.rs already has good docs, just the UNKNOWN_TOKEN_ID collision with IDENTITY_ID_1 needs a comment

Will use Codex with incremental commits. Targeting v3.1-dev.

[thepastaclaw]

Done: dashpay/platform#3131

3 commits:

• 90d4b6dcf — C01: Replace println with assertions in 5 DPNS tests
• 7607693ac — I02/I03: Add assertions to identity balance tests + 2 new error path tests
• dd419f8e2 — Document magic values in test fixtures

Compilation verified with cargo check -p dash-sdk --features=mocks --tests.