fix: speed up BMF→ILP closed-loop test (36s → 0.01s)

Use ILP solver on target + brute force on source instead of brute-force
enumerating all 2^24 ILP configurations.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: GiggleLiu

src/unit_tests/rules/bmf_ilp.rs

@@ -1,9 +1,7 @@
 use super::*;
 use crate::models::algebraic::{ObjectiveSense, ILP};
-use crate::rules::test_helpers::assert_optimization_round_trip_from_optimization_target;
+use crate::rules::test_helpers::assert_bf_vs_ilp;
 use crate::rules::{ReduceTo, ReductionResult};
-use crate::solvers::{BruteForce, ILPSolver};
-use crate::traits::Problem;
 
 #[test]
 fn test_bmf_to_ilp_structure() {
@@ -18,33 +16,18 @@ fn test_bmf_to_ilp_structure() {
 
 #[test]
 fn test_bmf_to_ilp_closed_loop() {
-    // 2x2 identity, rank 2 — exact factorization exists
+    // 2x2 identity, rank 2 — exact factorization exists.
+    // Use ILP solver on target (fast) + brute force on source (tiny 2x2).
     let problem = BMF::new(vec![vec![true, false], vec![false, true]], 2);
     let reduction: ReductionBMFToILP = ReduceTo::<ILP<bool>>::reduce_to(&problem);
-    assert_optimization_round_trip_from_optimization_target(
-        &problem,
-        &reduction,
-        "BMF->ILP closed loop",
-    );
+    assert_bf_vs_ilp(&problem, &reduction);
 }
 
 #[test]
 fn test_bmf_to_ilp_bf_vs_ilp() {
     let problem = BMF::new(vec![vec![true, true], vec![true, false]], 1);
     let reduction: ReductionBMFToILP = ReduceTo::<ILP<bool>>::reduce_to(&problem);
-
-    let bf = BruteForce::new();
-    let bf_witness = bf.find_witness(&problem).expect("should have a witness");
-    let bf_value = problem.evaluate(&bf_witness);
-
-    let ilp_solver = ILPSolver::new();
-    let ilp_solution = ilp_solver
-        .solve(reduction.target_problem())
-        .expect("ILP should be solvable");
-    let extracted = reduction.extract_solution(&ilp_solution);
-    let ilp_value = problem.evaluate(&extracted);
-
-    assert_eq!(bf_value, ilp_value);
+    assert_bf_vs_ilp(&problem, &reduction);
 }
 
 #[test]