# sporel-module-lib-core.selection-test

P.3.6 reference test-module — validates `lib-core.selection` API contracts
via the `engine.test.*` assertion surface.

- Module-ID: `lib-core.selection-test`
- Version: `0.1.0`
- Kind: `test-module` (headless; runs init() once + exits)
- Spec: `meta/docs/superpowers/specs/2026-05-14-p3-6-lib-selection-design.md`

## Run

```bash
Sporel.exe --test-libs=lib-core.selection-test
```

Output is TAP version 13 on stdout; exit-code = failure-count (0 = all pass).

## Coverage Statements (2026-05-16 Fault-Injection Audit)

Verified via deliberate-mutation in fixture-mirror; mutations reverted after observation.

### Caught Mutations

| # | Mutation | Caught by |
|---|---|---|
| M1 | `M.contains` prefixed with `do return false end` (always false) | Assertions "add → contains" (ok 6) and "toggle adds when absent" (ok 9) — 2 failures |
| M2 | `M.count` prefixed with `do return 0 end` (always zero) | Assertion "count = 1 after add" (ok 7) — expected 1 got 0 |

### Uncaught Mutations (Gaps)

| # | Mutation | Why uncaught | Severity |
|---|---|---|---|
| M3 | `M.add` unregistered-handle guard removed (any handle accepted silently) | No test calls `add(unregistered_handle)` and expects an error | Medium |

**Resolution per Gap:**
- Gap M3: Cheap-fill applied — two `pcall` error assertions added for `add(99999)` and `toggle(99999)` (commit see below).

### Cheap-Gap-Fills Applied

| Gap | New Assertion | Re-Inject Verifies |
|---|---|---|
| M3 | `add(unregistered) errors` — `pcall(function() selection.add(99999) end)` must return false | ✓ |
| M3 | `toggle(unregistered) errors` — `pcall(function() selection.toggle(99999) end)` must return false | ✓ |

### Tested Production-Lib Surface

`lib-core.selection` v0.1.0 — Tests cover: `register`, `unregister`, `count_registered`, `is_empty`, `count`, `contains`, `add`, `remove`, `toggle`, `clear`, `drag_threshold`, `set_drag_threshold`, `drag_state`, `box_rect`, `enabled`, `set_enabled`, `set_drag_box_color`, `drag_box_color`, `set_highlight_color`, `highlight_color`.