Aura/crates/aura-composites/tests/cost_graph.rs

//! `cost_graph` composite-builder: it fans the 4 PM-geometry inputs to N cost
//! nodes, surfaces each node's extra inputs as `cost[k].<port>` roles, and exposes
//! `CostSum`'s 3-field aggregate. These tests pin the exposed wiring contract (the
//! input-role set + the output triple); value byte-identity is the CLI goldens' job.

use aura_composites::cost_graph;
use aura_core::Scalar;
use aura_strategy::{ConstantCost, VolSlippageCost};

/// Two heterogeneous cost nodes: ConstantCost (no extras, index 0) and
/// VolSlippageCost (one extra `volatility`, index 1). The composite exposes the 4
/// geometry roles + the namespaced `cost[1].volatility`, and the 3-field aggregate.
#[test]
fn cost_graph_exposes_geometry_and_namespaced_extras() {
    let cg = cost_graph(vec![
        ConstantCost::builder().bind("cost_per_trade", Scalar::f64(2.0)),
        VolSlippageCost::builder().bind("slip_vol_mult", Scalar::f64(0.5)),
    ]);
    let roles: Vec<&str> = cg.input_roles().iter().map(|r| r.name.as_str()).collect();
    assert_eq!(
        roles,
        vec!["closed", "open", "entry_price", "stop_price", "cost[1].volatility"]
    );
    let outs: Vec<&str> = cg.output().iter().map(|o| o.name.as_str()).collect();
    assert_eq!(outs, vec!["cost_in_r", "cum_cost_in_r", "open_cost_in_r"]);
}

/// A lone cost node with no extras exposes only the 4 geometry roles (the n=1
/// shape), plus the 3-field aggregate.
#[test]
fn cost_graph_single_node_has_no_extra_roles() {
    let cg = cost_graph(vec![
        ConstantCost::builder().bind("cost_per_trade", Scalar::f64(2.0)),
    ]);
    let roles: Vec<&str> = cg.input_roles().iter().map(|r| r.name.as_str()).collect();
    assert_eq!(roles, vec!["closed", "open", "entry_price", "stop_price"]);
    let outs: Vec<&str> = cg.output().iter().map(|o| o.name.as_str()).collect();
    assert_eq!(outs, vec!["cost_in_r", "cum_cost_in_r", "open_cost_in_r"]);
}

/// Property: `cost_graph` composes an ARBITRARY number of cost nodes — the
/// cycle-0084 headline that retired the hardcoded `MAX_RUN_COST_NODES = 2` cap —
/// and namespaces each extra-bearing node's inputs by the node index, so two
/// same-typed factors never collide. Three nodes (ConstantCost at idx 0 with no
/// extras, then two VolSlippageCost at idx 1 and 2, each carrying a `volatility`
/// extra) must expose the 4 SHARED geometry roles plus the two DISTINCT
/// `cost[1].volatility` / `cost[2].volatility` roles, and still collapse to the
/// single 3-field aggregate output regardless of arity. The shipped n=2 fixture
/// has only one extra-bearing node, so it cannot witness a cross-node collision:
/// a mis-indexed `k`, or extras flattened to a bare `volatility`, would alias the
/// two nodes' inputs into one role and silently mis-feed the cost graph — this
/// n=3 two-extra fixture fails loudly on that class while the n=1/n=2 fixtures
/// stay green.
#[test]
fn cost_graph_arbitrary_arity_namespaces_each_extra_by_node_index() {
    let cg = cost_graph(vec![
        ConstantCost::builder().bind("cost_per_trade", Scalar::f64(2.0)),
        VolSlippageCost::builder().bind("slip_vol_mult", Scalar::f64(0.5)),
        VolSlippageCost::builder().bind("slip_vol_mult", Scalar::f64(0.25)),
    ]);
    let roles: Vec<&str> = cg.input_roles().iter().map(|r| r.name.as_str()).collect();
    assert_eq!(
        roles,
        vec![
            "closed",
            "open",
            "entry_price",
            "stop_price",
            "cost[1].volatility",
            "cost[2].volatility",
        ]
    );
    let outs: Vec<&str> = cg.output().iter().map(|o| o.name.as_str()).collect();
    assert_eq!(outs, vec!["cost_in_r", "cum_cost_in_r", "open_cost_in_r"]);
}

/// Property: the 4 PM-geometry inputs are FANNED (shared once) across every cost
/// node, never duplicated per node — so N extra-free cost nodes expose exactly the
/// 4 geometry roles and ZERO `cost[k]` roles, independent of N. Two extra-free
/// ConstantCost nodes must expose only `[closed, open, entry_price, stop_price]`
/// (and the 3-field aggregate). The shipped single-node fixture has N=1, so it
/// cannot catch a regression that per-node-duplicated the geometry into
/// `cost[k].closed`-style roles, or that leaked a spurious `cost[k]` role for an
/// extra-free node; this multi-node extra-free fixture pins the fan-once contract.
#[test]
fn cost_graph_fans_shared_geometry_across_multiple_extra_free_nodes() {
    let cg = cost_graph(vec![
        ConstantCost::builder().bind("cost_per_trade", Scalar::f64(2.0)),
        ConstantCost::builder().bind("cost_per_trade", Scalar::f64(1.0)),
    ]);
    let roles: Vec<&str> = cg.input_roles().iter().map(|r| r.name.as_str()).collect();
    assert_eq!(roles, vec!["closed", "open", "entry_price", "stop_price"]);
    let outs: Vec<&str> = cg.output().iter().map(|o| o.name.as_str()).collect();
    assert_eq!(outs, vec!["cost_in_r", "cum_cost_in_r", "open_cost_in_r"]);
}