Elamur Groupantsmlab-tests-vm-synthetic-parity
The groupant beside mlab/tests/vm.rs in the Mova repository: what the code computes, what it never does, how to go back from its outputs, its invariants, cost and checks.
Facts
Implementation material. A Mova code model describes this code at one source revision: partial models, finite checks and their stated scope. It is not a reviewed general exposition, and its labels are shown as written, never raised.
Components
| component | label | where |
|---|---|---|
| approximant | partial | approximant |
| ast | partial | ../syntax.json |
| cost | symbolic source derived | invariant |
| descriptant | present | descriptant |
| invariant | partial | invariant |
| tests | executed bounded checks | tests |
Obernants
The typed relations around the forward model: the behaviour complement (what the code never does), the reverse reconstruction (every input compatible with an output) and specialised views.
| id | type | label | where |
|---|---|---|---|
behavior_complement | behavior_complement | partial source derived model | behavior_complement |
reverse_reconstruction | reverse_reconstruction | partial source derived model | reverse_reconstruction |
cow_fixture | cow_fixture | partial source derived model | cow_fixture |
short_circuit_fixture | short_circuit_fixture | partial source derived model | short_circuit_fixture |
dynamic_fixture | dynamic_fixture | partial source derived model | dynamic_fixture |
loop_fixture | loop_fixture | partial source derived model | loop_fixture |
Model text
descriptant
mlab-tests-vm-synthetic-parity
Seven bounded arithmetic, COW, loop, fallback, short-circuit, capture and string fixtures.
Epoch 2026-10-31
Half-open source bytes [9417,10511); bound by parent source hash and scoped byte hash. Model covers only this fragment; parent composition explains joins.
approximant
Scoped forward relation
For each fixture assert tree bytes equal fixed oracle and VM bytes equal tree; assert fallback/dyn counters on separate fixture.
Domain and gap
Source-generated states within resource limits. Categorical relation has no executable percent surrogate.
invariant
Scoped invariant
A(1,2) stays2 while B(1,2) becomes9.
Cost
Seven finite programs and one counter fixture; largest matrix2x2 and range3..1. Includes repeated tree/VM construction, no timing claim.
models
Scoped typed relations
behavior_complement
The fixed COW oracle excludes both matrices changing; short-circuit fixture excludes missing-function diagnostics; empty-loop fixture excludes printing99.
reverse_reconstruction
Passing result identifies agreement on finite fixtures only; the two engines can share bugs outside them.
cow_fixture
A(1,2) stays2 while B(1,2) becomes9.
short_circuit_fixture
missing_wave30 is not called by false&& or true||.
dynamic_fixture
String array indexing crosses DynEval; cell construction/clear cause fallback.
loop_fixture
3:-1:1 sums6; [] executes no body.
tests
Evidence scope
Parent selected tests: wave30_bounded_state_and_fallback, wave30_parse_runtime_and_output_state, wave30_synthetic_gate_fail_fast, vm_workspace_is_visible_after_run. This fragment shares parent syntax and finite checks; no separate test count or complete fragment coverage claim. Assertion-control association and unexecuted paths are in parent tests.md and source-test-map.json.
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