---
title: "algorithm-treap-tests — Mova code model"
description: "Mova code model of algorithms/src/treap/tests.rs: components with their labels, obernants and the model text."
url: "https://groupants.elamur.ai/free/en/mova/algorithms/src/treap/tests.rs.groupant/"
---
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# algorithm-treap-tests

The groupant beside algorithms/src/treap/tests.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

- **kind:** groupant
- **status:** partial source derived instance
- **source:** [`algorithms/src/treap/tests.rs`](https://github.com/ElamurAI/mova-free/blob/main/algorithms/src/treap/tests.rs)
- **source SHA-256:** `99553fa8bbb480a7…`
- **repository folder:** [`algorithms/src/treap/tests.rs.groupant`](https://github.com/ElamurAI/mova-free/tree/main/algorithms/src/treap/tests.rs.groupant)
- **repository commit:** `855da7bd4a7b`

> **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 | [Forward](#forward) |
| **ast** | partial | `syntax.json` |
| **cost** | conditional | [Cost](#cost) |
| **descriptant** | present | [descriptant](#descriptant) |
| **invariant** | partial | [Invariant](#invariant) |
| **tests** | bounded executed | [evidence](#evidence) |

## 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 relational specification | [behavior_complement](#behavior-complement) |
| `reverse_reconstruction` | reverse_reconstruction | partial relational specification | [reverse_reconstruction](#reverse-reconstruction) |
| `oracle_independence` | oracle_independence | partial relational specification | [oracle_independence](#oracle-independence) |
| `mutation_sensitivity` | mutation_sensitivity | partial relational specification | [mutation_sensitivity](#mutation-sensitivity) |
| `finite_schedule` | finite_schedule | partial relational specification | [finite_schedule](#finite-schedule) |

## Model text


### descriptant

#### Explicit-priority bounded treap tests

Original std-only Rust implementation and fixtures. Reference: Seidel and Aragon, Randomized Search Trees, Algorithmica 16, 1996.

##### Prospective epoch, 2026-10-30

Domain, recurrence, invariants, costs and validation plan were saved before implementation in $MOVA_DATA/runs/octopus-wave26-indexes-2026-10-30/prospective.md. No runtime gain was predicted or measured.

##### Executed epoch, 2026-10-30

Two tests: exhaustive_operation_oracle and priorities_capacity_and_reuse.

All46656 six-step operation schedules over insert/remove of three keys, alternating explicit priorities; compare to BTreeSet after each step and independently check BST bounds, heap, parent pointers, reachability and free-list partition. Capacity4096, linear-height priorities, reuse after2048 deletions, ties and integer extrema.

##### Limits

Exact bounded APIs only. No generic 1/2/5/10% accuracy surrogate is supported. Finite tests do not prove universal correctness or runtime gains. Standard Vec/Box/BTreeMap allocation failure may abort or panic; allocator refusal is not injected. No callbacks, I/O or concurrency effects.
Partial Rust syntax is source-bound; macro expansion, semantic AST proof and whole-Mova quality remain gaps.

### model

## Mathematical model

### Forward

Execute deterministic fixtures, compare exact API values and state against independent finite oracles, then report success iff all assertions hold. All46656 six-step operation schedules over insert/remove of three keys, alternating explicit priorities; compare to BTreeSet after each step and independently check BST bounds, heap, parent pointers, reachability and free-list partition. Capacity4096, linear-height priorities, reuse after2048 deletions, ties and integer extrema.

### Invariant

Fixtures are deterministic, production and oracle observations are compared exactly; state checks inspect parent edges and order where relevant. Assertions fail on disagreement; no benchmark thresholds enter correctness.

### Cost

Bounded finite enumeration plus production/oracle work; exhaustive here means the documented small fixture universe only. Runs use ordinary allocator behavior; resource failure is not injected.

### behavior_complement

For terminating finite harness executions, reports that disagree with the conjunction of assertions are excluded. Passing a candidate with any fixture mismatch is absent from the specified relation. Abort/nontermination are outside the observation universe; this relation is not a universal production correctness proof.

### reverse_reconstruction

A pass admits every implementation agreeing on these finite observations, including implementations differing arbitrarily outside the fixtures. A failure admits production defects or oracle defects; the report alone does not uniquely reconstruct the cause.

### oracle_independence

All46656 six-step operation schedules over insert/remove of three keys, alternating explicit priorities; compare to BTreeSet after each step and independently check BST bounds, heap, parent pointers, reachability and free-list partition. Capacity4096, linear-height priorities, reuse after2048 deletions, ties and integer extrema.

### mutation_sensitivity

Negate public contains result; exhaustive_operation_oracle must fail. Source bytes are restored before the successful positive rerun. These controls establish sensitivity only to the chosen defects.

### finite_schedule

Two tests: exhaustive_operation_oracle and priorities_capacity_and_reuse. Counts and repeat receipts are retained externally; neither repeatability nor test count guarantees unseen behavior.

### Gaps

Exact bounded APIs only. No generic 1/2/5/10% accuracy surrogate is supported. Finite tests do not prove universal correctness or runtime gains. Standard Vec/Box/BTreeMap allocation failure may abort or panic; allocator refusal is not injected. No callbacks, I/O or concurrency effects.

### evidence

#### Evidence, 2026-10-30

Four identical normalized runs: 706 tests; 14 new tests.
kd_tree: compiled production mutant exit Some(101), named assertion exhaustive_grid_oracle; exact restoration and positive rerun exit Some(0).
bk_tree: compiled production mutant exit Some(101), named assertion exhaustive_metric_oracle; exact restoration and positive rerun exit Some(0).
interval_tree: compiled production mutant exit Some(101), named assertion exhaustive_closed_overlap_oracle; exact restoration and positive rerun exit Some(0).
treap: compiled production mutant exit Some(101), named assertion exhaustive_operation_oracle; exact restoration and positive rerun exit Some(0).
splay_tree: compiled production mutant exit Some(101), named assertion exhaustive_stateful_oracle; exact restoration and positive rerun exit Some(0).

Strict mova-algorithms all-target Clippy passed; focused rustfmt passed. Receipts: $MOVA_DATA/runs/octopus-wave26-indexes-2026-10-30. Two freshly generated syntax projections must compare identical before syntax.json installation. No benchmark or training/quality measurement is claimed.

For this module: Two tests: exhaustive_operation_oracle and priorities_capacity_and_reuse.