Elamur Groupantsmlab-tests-fs
The groupant beside mlab/tests/fs.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 |
| composition | partial | composition |
| 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 |
state_invariant | state_invariant | partial source derived model | state_invariant |
failure_precedence | failure_precedence | partial source derived model | failure_precedence |
representation_transport | representation_transport | partial source derived model | representation_transport |
resource_cost | resource_cost | partial source derived model | resource_cost |
Model text
descriptant
mlab-tests-fs
VFS parity, isolation, limits and CLI tests with temporary directory guards; frozen suite tests exist but were not selected.
Modeling epoch — 2026-10-31
Prospective source read preceded edits. Bounded synthetic checks and selected existing safe tests exercise actual code; paired debug/release results and compiled negative-control assertions are retained externally. Frozen scenario, corpus, external measurement, full-school and training effects are unexecuted. Partial lexical syntax supplies no macro-expanded or semantic proof.
approximant
Forward relation
scratch creates PID/tag directory, Scratch Drop removes it; run_with creates captured interpreter with supplied backend and vm flag. Selected tests exercise memory invisibility, configured limits and CLI import/export/journal or rooted temp backend.
Domain
Valid Rust value/storage invariants and available bounded resources; exact branch and effect observations only.
Executable approximant gap
No useful percentage-error surrogate is established for these categorical, textual or effectful observations. Supported future caps are 1%, 2%, 5%, 10%; no executable approximation or production substitution is claimed.
invariant
Invariants and costs
Selected host paths are synthetic temporary roots; guard cleanup occurs on unwind. Frozen SUITES constants and scenarios are unchanged and not executed.
Failure ordering
Fixture setup unwraps and panics on filesystem failures; scratch removes prior same-PID/tag directory, so unique tags are part of safe test precondition. CLI output decodes lossily.
Cost
Bounded fixture cost plus interpreter and spawned CLI startup; no performance claim. Unselected suite loops would scale by scenario count and backend pairs.
composition
Composition
scratch creates PID/tag directory, Scratch Drop removes it; run_with creates captured interpreter with supplied backend and vm flag. Selected tests exercise memory invisibility, configured limits and CLI import/export/journal or rooted temp backend.
CLI helper returns status code or -1, stdout and stderr strings. No claim that empty stderr alone proves success; fixtures assert explicit code.
Interaction limit
Local fragment relations compose only with valid Value storage, caller error propagation and delegated providers. They do not establish whole-interpreter or host-filesystem guarantees.
models
Typed models — mlab-tests-fs
Source-derived partial relations; finite checks do not prove universality.
behavior_complement
A memory write excludes creation of the corresponding host probe in the selected isolation assertion. Failed script excludes exported file in CLI fixture. Unselected frozen parity functions supply no epoch runtime evidence.
reverse_reconstruction
Passing fixture assertions admits many implementations beyond exercised cases; captured output alone cannot recover filesystem effect trace, so tests also inspect paths/journal.
state_invariant
Selected host paths are synthetic temporary roots; guard cleanup occurs on unwind. Frozen SUITES constants and scenarios are unchanged and not executed.
failure_precedence
Fixture setup unwraps and panics on filesystem failures; scratch removes prior same-PID/tag directory, so unique tags are part of safe test precondition. CLI output decodes lossily.
representation_transport
CLI helper returns status code or -1, stdout and stderr strings. No claim that empty stderr alone proves success; fixtures assert explicit code.
resource_cost
Bounded fixture cost plus interpreter and spawned CLI startup; no performance claim. Unselected suite loops would scale by scenario count and backend pairs.
tests
Evidence and limitations
Selected named outcomes: default_fs_is_memory_and_invisible_outside, fs_limits_fire_with_clear_errors, cli_import_export_journal, cli_dir_mode_reads_and_writes_inside_root_only. Each ran twice debug and twice release with sorted identical nonempty outcomes and numeric exit 0. Source-specific compiled control exercised "default_fs_is_memory_and_invisible_outside": compile exit 0, assertion-red exit 101, exact-restored rerun exit 0. External receipts: octopus-wave30-io-2026-10-31 (native-commands.json, positive-receipts.json, controls.json).
Scope: Selected host paths are synthetic temporary roots; guard cleanup occurs on unwind. Frozen SUITES constants and scenarios are unchanged and not executed.
AST projection generated twice to fresh files and compared byte-for-byte. Runtime evidence is finite and does not establish every branch, allocation failure, backend implementation or effect path. No optimization or speed claim.
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