[TST-E4] test: thirteen more declared-error doors become table rows, each area's rows in its own slice

[Blind-Striker]

📝 Description

What does this PR do?
It is TST-E4a's first batch of declared-error door conversions. Thirteen methods move into the door table that #446 introduced: four in Config, four in Credentials, two in Debug, one in Experimental/FileWrite and two in Forms. Each of these methods proved only "door D answers declared status S with error type T", on one spine.

• Each becomes a row, and every row runs on both spines. On the throwing spine it asserts OpenCodeApiException, the exact status and the exact type. On the NoThrow spine it asserts IsError, the exact status and the exact type. Each row is also checked against its declaration in the pinned spec/openapi.json by the one-way guard.
• Each area's rows live in its own slice: Config/ConfigDeclaredErrors.cs, Credentials/…, Debug/…, Experimental/… and Forms/…, each with a static Rows() of 17 to 61 lines. DeclaredErrorTests.EveryDoor() is only their concatenation, so both spines and the guard still read one row source. The pilot row moves verbatim to Worktrees/WorktreesDeclaredErrors.cs. This layout keeps the table inside analyzer MA0051's 80-line method limit and the slice layout, as the table grows to about 100 rows.
• Every other method in the touched classes is byte-identical. No product, record or test-method change.

Net line delta: +286 / −192 = +94 in test code. The conversions do not save lines; the six slice files add their own class scaffolding. The gains are fewer methods, coverage on both spines, and each row traced to the pin.

🔄 Type of Change

• 🧪 Test improvements

🎯 Protocol & API Surface

• No change to the public API surface
• Nothing under external/, spec/ or src/ was touched

🧪 Testing

Test mapping (mechanical: e4_test_map.py over git diff 7738dc33 d61b521f)

File	Base test method	At head	Target
tests/OpenCode.Sdk.Tests/Config/ConfigClientContractTests.cs	GetShellsAsync_Should_Throw_The_Declared_400_Error	row	config.shells:400:InvalidRequestError
tests/OpenCode.Sdk.Tests/Config/ConfigClientContractTests.cs	GetShellsAsync_Should_Return_The_401_Error_On_The_NoThrow_Spine	row	config.shells:401:UnauthorizedError
tests/OpenCode.Sdk.Tests/Config/ConfigClientContractTests.cs	UpdateConfigAsync_Should_Throw_The_Declared_400_Error	row	experimental.config.update:400:InvalidRequestError
tests/OpenCode.Sdk.Tests/Config/ConfigClientContractTests.cs	UpdateConfigAsync_Should_Return_The_401_Error_On_The_NoThrow_Spine	row	experimental.config.update:401:UnauthorizedError
tests/OpenCode.Sdk.Tests/Credentials/CredentialsClientContractTests.cs	CreateCredentialAsync_Should_Return_The_Declared_409_Error_On_The_NoThrow_Spine	row	credential.create:409:ConflictError
tests/OpenCode.Sdk.Tests/Credentials/CredentialsClientContractTests.cs	ListCredentialsAsync_Should_Throw_The_Declared_401_Error	row	credential.list:401:UnauthorizedError
tests/OpenCode.Sdk.Tests/Credentials/CredentialsClientContractTests.cs	ActivateCredentialAsync_Should_Throw_The_Declared_400_Error	row	credential.activate:400:InvalidRequestError
tests/OpenCode.Sdk.Tests/Credentials/CredentialsClientContractTests.cs	ActivateCredentialAsync_Should_Return_The_401_Error_On_The_NoThrow_Spine	row	credential.activate:401:UnauthorizedError
tests/OpenCode.Sdk.Tests/Debug/DebugClientContractTests.cs	ListLocationsAsync_Should_Throw_The_Declared_400_Error	row	debug.location.list:400:InvalidRequestError
tests/OpenCode.Sdk.Tests/Debug/DebugClientContractTests.cs	ListLocationsAsync_Should_Return_The_401_Error_On_The_NoThrow_Spine	row	debug.location.list:401:UnauthorizedError
tests/OpenCode.Sdk.Tests/Experimental/FileWriteContractTests.cs	WriteFileAsync_Should_Throw_The_Declared_400_Error	row	experimental.fs.write:400:InvalidRequestError
tests/OpenCode.Sdk.Tests/Forms/FormsClientContractTests.cs	ListFormsAsync_Should_Throw_The_Declared_400_Error	row	form.list:400:InvalidRequestError
tests/OpenCode.Sdk.Tests/Forms/FormsClientContractTests.cs	ListFormsAsync_Should_Return_The_401_Error_On_The_NoThrow_Spine	row	form.list:401:UnauthorizedError

Unmapped: 0

File	Assert.That at base	at head	delta
tests/OpenCode.Sdk.Tests/Common/Errors/DeclaredErrorTests.cs	12	12	+0
tests/OpenCode.Sdk.Tests/Config/ConfigClientContractTests.cs	26	14	-12
tests/OpenCode.Sdk.Tests/Config/ConfigDeclaredErrors.cs	0	0	+0
tests/OpenCode.Sdk.Tests/Credentials/CredentialsClientContractTests.cs	39	27	-12
tests/OpenCode.Sdk.Tests/Credentials/CredentialsDeclaredErrors.cs	0	0	+0
tests/OpenCode.Sdk.Tests/Debug/DebugClientContractTests.cs	11	5	-6
tests/OpenCode.Sdk.Tests/Debug/DebugDeclaredErrors.cs	0	0	+0
tests/OpenCode.Sdk.Tests/Experimental/ExperimentalDeclaredErrors.cs	0	0	+0
tests/OpenCode.Sdk.Tests/Experimental/FileWriteContractTests.cs	9	6	-3
tests/OpenCode.Sdk.Tests/Forms/FormsClientContractTests.cs	13	7	-6
tests/OpenCode.Sdk.Tests/Forms/FormsDeclaredErrors.cs	0	0	+0
tests/OpenCode.Sdk.Tests/Worktrees/WorktreesDeclaredErrors.cs	0	0	+0

The negative deltas are the deleted methods' assertions. The rows assert the same status and exact type on both spines; DeclaredErrorTests' 12 assertion sites run for every row.

Equivalence mutants: one per source class (scratch only; restored byte-identically)

In each class's response adapter, the declared tags for one door's status were emptied.

Adapter (src/OpenCode.Sdk/)	Old method, red on base	New row, red on both spines
Config/Internal/ConfigShellsResponseAdapter.cs:9	GetShellsAsync_Should_Throw_The_Declared_400_Error	config.shells:400:InvalidRequestError
Credentials/Internal/CredentialCreateResponseAdapter.cs:11	CreateCredentialAsync_Should_Return_The_Declared_409_Error_On_The_NoThrow_Spine	credential.create:409:ConflictError
Debug/Internal/DebugLocationListResponseAdapter.cs:9	ListLocationsAsync_Should_Throw_The_Declared_400_Error	debug.location.list:400:InvalidRequestError
Experimental/Internal/ExperimentalFsWriteResponseAdapter.cs:9	WriteFileAsync_Should_Throw_The_Declared_400_Error	experimental.fs.write:400:InvalidRequestError
Forms/Internal/FormListResponseAdapter.cs:9	ListFormsAsync_Should_Throw_The_Declared_400_Error	form.list:400:InvalidRequestError

Base: 5 failed. Finished table: 10 failed (5 rows × 2 spines). Every failure received UnknownOpenCodeError at the exact-type assertion. Two row-oracle mutants are also killed: a wrong expected type turns both spines red, and a pointer into another operation turns the guard red.

Clone baseline (regenerated, totals fall)

	Master 7738dc33	This PR
Test clones	641	603
Tests duplication	5.35%	5.12%

The baseline loses 98 fingerprints and gains 64. None of the 62 duplicates jscpd reports as new involves a file this PR changes. Every one sits between files this PR does not touch, whose text is byte-identical to master. They are the not-yet-converted declared-error methods: once their Config, Credentials and other twins are deleted, jscpd reports their remaining duplicates under new pairings and new fingerprints. 22 of them map to a same-pair predecessor; the other 40 are the same unchanged fragments paired differently. They shrink as later door PRs convert those methods.

Review

• Coordinator: read the diff and the slice layout. One note for later: two cases of the same door repeat the door definition. That is not repeated per spine and not a detected clone, but a shared door per area could tighten it.
• Sol (given only the requirements and the diff) found no defects and no out-of-scope changes. It checked every row against spec/openapi.json and matched all 14 nameof labels to the call their lambda makes. It could not verify the baseline-regrouping claim from hashes alone; the jscpd analysis above is that evidence.

✅ Completion Gate

Local check (quality-gates.md) on head d61b521f, base 7738dc33. Every step's own exit code was read:

• slopwatch: zero findings
• dotnet build --configuration Release: 0 warnings, 0 errors
• dotnet format whitespace / dotnet format style --severity warn: no changes
• verify-clones: passed, 0 new (tests 5.12%)
• OpenCode.Sdk.Tools.Tests (all but NativeAot): 2081, 0 failed
• OpenCode.Sdk.Tests (all but ServiceElection/NativeAot): 8519, 0 failed

The host runs Bun 1.4.3, a maintainer-named off-pin host (OPENCODE_SDK_TESTS_BUN_MISMATCH=allow); the pin is 1.4.2.

✅ Code Quality Checklist

• No new suppression
• No tests skipped or weakened; every removed method is mapped to its row above

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