---
name: semantics-testing
description: Core protocol for Test Constraints, External Ontology, Graph Noise Reduction, and Invariant Traceability for Python (pytest) and Svelte (vitest) projects.
---

#region Std.Semantics.Testing [C:5] [TYPE Skill] [SEMANTICS testing,qa,verification,pytest,vitest]
@BRIEF HOW to write tests: constraints, external ontology, graph noise reduction, and invariant traceability for pytest and vitest.
@RELATION DEPENDS_ON -> [Std.Semantics.Core]
@RELATION DEPENDS_ON -> [Std.Semantics.Svelte]
@INVARIANT Test modules must trace back to production @INVARIANT tags without flooding the Semantic Graph with orphan nodes.
@RATIONALE Test contracts trace to production @INVARIANT/@POST tags via @TEST_INVARIANT, preventing orphan nodes. pytest+vitest dual stack eliminates cross-language tooling overhead. 3-edge-case floor balances coverage sufficiency against graph noise. Hardcoded fixtures block logic-mirror tautology — the dominant LLM test-generation failure mode where the agent re-implements the production algorithm inside the test as `expected = compute(x)`. The test always passes but proves nothing because it's a copy of what it's testing.
@REJECTED Property-based testing — non-deterministic input space creates unbounded graph edges, irreducible to fixed-scenario tracing. Snapshot testing — brittle to CSS/UI changes without invariant signal. Integration-only (no unit tests) — coarse graph edges miss localized @INVARIANT violations. Cucumber/Gherkin BDD — DSL layer breaks direct traceability to Python/Svelte @POST anchors. Dynamic expected-value computation — `expected = production_fn(x)` is a tautology, not a test; hardcoded fixtures are the only valid approach.

## 0. QA RATIONALE (LLM PHYSICS IN TESTING)

You are an Agentic QA Engineer. Your primary failure modes are:
1. **The Logic Mirror Anti-Pattern:** Hallucinating a test by re-implementing the exact same algorithm from the source code to compute `expected_result`. This creates a tautology (a test that always passes but proves nothing).
2. **Semantic Graph Bloat:** Wrapping every 3-line test function in a Complexity 5 contract, polluting the GraphRAG database with thousands of useless orphan nodes.
Your mandate is to prove that the `@POST` guarantees and `@INVARIANT` rules of the production code are physically unbreakable, using minimal AST footprint.

## I. EXTERNAL ONTOLOGY (BOUNDARIES)

When writing code or tests that depend on 3rd-party libraries or shared schemas that DO NOT have local anchors in our repository, you MUST use strict external prefixes.
**CRITICAL RULE:** Do NOT hallucinate anchors for external code.

1. **External Libraries (`[EXT:Package:Module]`):**
   - Use for 3rd-party dependencies.
   - Example: `@RELATION DEPENDS_ON -> [EXT:FastAPI:Router]` or `[EXT:SQLAlchemy:Session]`
   - Svelte: `[EXT:SvelteKit:load]`
2. **Shared DTOs (`[DTO:Name]`):**
   - Use for globally shared schemas, Pydantic models, or external registry definitions.
   - Example: `@RELATION DEPENDS_ON -> [DTO:DashboardExportPayload]`

## II. TEST MARKUP ECONOMY (NOISE REDUCTION)

To prevent overwhelming Semantic Graph, test files operate under relaxed complexity rules:
1. **Short hierarchical IDs:** Test modules use `Test.Domain.Name` format (e.g., `Test.Migration.RunTask`), not full file paths or flat names. This satisfies ATTN_2: the `Test.` prefix groups all tests under HCA 128× while the domain name provides DSA Indexer grouping.
2. **Root Binding (`BINDS_TO`):** Do NOT map the internal call graph of a test file. Instead, anchor the entire test suite to the production module using: `@RELATION BINDS_TO -> [TargetModule]`.
3. **Complexity 1 for Helpers:** Small test utilities (e.g., `_setup_mock`, `_build_payload`) are **C1**. They require ONLY the anchor pair. No `@BRIEF` or `@RELATION` allowed.
4. **Complexity 2 for Tests:** Actual test functions (e.g., `test_unauthorized_access`) are **C2**. They require anchor + `@BRIEF`. Do not add `@PRE`/`@POST` to individual test functions.
5. **Maximum test file size:** A single test file MUST NOT exceed **600 lines**. Beyond this threshold:
   - Split into multiple test files by domain (e.g., `test_auth_flow.py`, `test_auth_ws.py` instead of `test_auth.py`).
   - Extract shared fixtures into a `conftest.py` in the same directory.
   - Each test class tests ONE production contract — if a file has more than 3 test classes, split by class.
   - **Exception:** Integration test files using Testcontainers may be up to **800 lines** due to longer setup/teardown.
   - **RATIONALE:** Files >600 lines degrade the model's sliding-window attention — the bottom of the file is compressed before the top is applied, leading to duplicate tests and orphan contracts.

## III. TRACEABILITY & TEST CONTRACTS

In the Header of your Test Module, you MUST define the Test Contracts. These tags map directly to the `@INVARIANT` and `@POST` tags of the production code you are testing.
- `@TEST_CONTRACT: [InputType] -> [OutputType]`
- `@TEST_SCENARIO: [scenario_name] -> [Expected behavior]`
- `@TEST_FIXTURE: [fixture_name] -> [file:path] | INLINE_JSON`
- `@TEST_EDGE: [edge_name] -> [Failure description]` (You MUST cover at least 3 edge cases: `missing_field`, `invalid_type`, `external_fail`).
- **The Traceability Link:** `@TEST_INVARIANT: [Invariant_Name_From_Source] -> VERIFIED_BY: [scenario_1, edge_name_2]`

## IV. ADR REGRESSION DEFENSE

The Architectural Decision Records (ADR) and `@REJECTED` tags in production code are constraints.
If the production contract has a `@REJECTED [Forbidden_Path]` tag (e.g., `@REJECTED fallback to SQLite`), your Test Module MUST contain an explicit `@TEST_EDGE` scenario proving that the forbidden path is physically unreachable or throws an appropriate error.
Tests are the enforcers of architectural memory.

## V. ANTI-TAUTOLOGY RULES

1. **No Logic Mirrors:** Use deterministic, hardcoded fixtures (`@TEST_FIXTURE`) for expected results. Do not dynamically calculate `expected = a + b` to test an `add(a, b)` function.
2. **Do Not Mock The System Under Test:** You may mock `[EXT:...]` boundaries (like DB drivers or external APIs), but you MUST NOT mock the local contract node you are actively verifying.

## VI. PYTHON / PYTEST CONVENTIONS

### Test file structure
```
backend/tests/
├── conftest.py           # Shared fixtures, mock setup (C3 Module)
├── test_auth.py          # Auth tests (C2 Module, BINDS_TO -> AuthService)
├── test_migration.py     # Migration tests
└── test_plugins/         # Plugin-specific tests
```

### Test module template
```python
# #region Test.Migration.RunTask [C:3] [TYPE Module] [SEMANTICS test,migration]
# @BRIEF Verify dashboard migration contracts — @POST guarantees and rejected paths.
# @RELATION BINDS_TO -> [Migration.RunTask]
# @TEST_EDGE: missing_db_mapping -> Migration fails with MappingError
# @TEST_EDGE: invalid_dashboard_id -> Migration fails with NotFoundError
# @TEST_EDGE: external_api_timeout -> Migration fails with TimeoutError, rolls back
import pytest
from unittest.mock import AsyncMock, patch

class TestDashboardMigration:
    """Verify migrate_dashboard @POST guarantees."""

    # #region test_migrate_dashboard_success [C:2] [TYPE Function]
    # @BRIEF Happy path: valid dashboard with complete db mapping.
    @pytest.mark.asyncio
    async def test_migrate_dashboard_success(self):
        # Use hardcoded fixture, not algorithmic computation
        expected = {"id": "dash_1", "status": "imported"}
        # ... test implementation
        pass
    # #endregion test_migrate_dashboard_success
# #endregion TestDashboardMigration
```

### Running tests
```bash
# All backend tests (integration tests skipped by default)
cd backend && source .venv/bin/activate && python -m pytest -v

# Specific test file
python -m pytest tests/test_migration.py -v

# Include integration tests (PostgreSQL/Superset Testcontainers)
python -m pytest --run-integration

# Run only integration tests
python -m pytest tests/integration/ --run-integration

# With coverage
python -m pytest --cov=src --cov-report=term-missing
```

**Integration tests** (`tests/integration/`) use Testcontainers (PostgreSQL 16, Superset 4.1.2)
and require Docker. They are **skipped by default** — pass `--run-integration` to enable.
The `--run-integration` flag is registered in `backend/tests/conftest.py` via `pytest_addoption`;
skip logic lives in `backend/tests/integration/conftest.py` via `pytest_collection_modifyitems`.
See also: `backend/pyproject.toml` `[tool.pytest.ini_options] markers` for the registered marker.

## VII. SVELTE / VITEST CONVENTIONS

### Test file structure
```
frontend/src/
├── lib/
│   ├── components/__tests__/   # Component tests
│   │   ├── MigrationTaskCard.test.js
│   │   └── StatusBadge.test.js
│   └── stores/__tests__/       # Store tests
│       └── taskDrawer.test.js
```

### Component test template
```javascript
import { render, screen, fireEvent } from "@testing-library/svelte";
import { describe, it, expect, vi } from "vitest";
import ComponentName from "../ComponentName.svelte";

describe("ComponentName", () => {
  it("renders with props", () => {
    const { container } = render(ComponentName, {
      props: { title: "Test", status: "idle" }
    });
    expect(container.textContent).toContain("Test");
  });

  it("shows loading state on action", async () => {
    // Use mock API, verify loading states
  });
});
```

### Running tests
```bash
# All frontend tests
cd frontend && npm run test

# Watch mode
npm run test:watch
```

## VIII. VERIFIABLE HARNESS RULES

For agentic development, a test harness is part of the task environment.
- Prefer real executable checks over narrative claims that a change is safe.
- Verify that the harness actually fails on the broken state and passes on the fixed state whenever feasible.
- Resist shortcut tests that bypass the real integration boundary the task is supposed to validate.
- When a production `@POST` guarantee is subtle, add the narrowest test that can falsify it.

## IX. LONG-HORIZON QA MEMORY

When multiple attempts are needed:
- Preserve the smallest set of failing fixtures, commands, and invariant mappings that explain the current gap.
- Fold older failed attempts into one bounded note describing what was tried and why it was rejected.
- Do not keep extending the active QA transcript with redundant command output.

## X. TESTING SEARCH DISCIPLINE

- Use one concrete failing hypothesis plus one verifier by default.
- Add alternative test strategies only when the first verifier is inconclusive.
- Do not mirror the implementation logic to fabricate expected values; use fixtures, explicit contracts, and invariant-oriented assertions.

#endregion Std.Semantics.Testing