indicatrix-cut 0.7.1

Desktop faceting-design editor: library browsing, spectral 3D rendering, material retargeting, and a solid inspection view.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
//! Tests for the retarget dialog's Slint-free decision logic, spanning
//! [`super::material`], [`super::proposal_view`], [`super::apply`], and
//! [`super::snapshot`] -- see this group's own `mod.rs` doc comment ("Slint-free
//! view-model split").

use super::{
    apply::{RetargetApplyError, apply_pending_retarget},
    material::{
        initial_target_index, resolve_target_selection, resolved_material_from_selection,
        target_display_name, target_material_selection,
    },
    proposal_view::{candidate_row_views, retarget_view, search_summary_line},
    snapshot::{diff_row_view, diff_rows_from_deltas},
};
use crate::gui::editor::{
    retarget::{AnchorChange, CrownShift, RetargetMode},
    state::{EditorState, design_material_index_from_name, design_material_options},
};
use indicatrix::{geometry::meet_solver::MeetConstraint, optics::materials::GemMaterial};
use indicatrix_cut_core::{
    ConstraintTier, Design, History, MaterialSelection, OptimizeConfig, PreformSpec,
    ResolvedMaterial, ScheduleMeta, diff_tiers,
};
use indicatrix_editor::retarget::{
    metrics::RetargetMetrics,
    search::{CandidateKind, CandidateNumbers, SearchCandidate, SearchReport, StartPoint},
    validity::{InvalidReason, RetargetValidity, ValidityStatus},
};
use std::sync::atomic::Ordering as AtomicOrdering;

/// Test-only convenience composing [`target_material_selection`] (the lenient,
/// production wrapper) with [`resolved_material_from_selection`] -- these tests
/// exercise the RESOLVED material, not the [`MaterialSelection`] on its own, and
/// production code no longer has a use for that exact composition (both real call
/// sites need the `Result`-returning [`resolve_target_selection`] instead, for
/// error surfacing).
fn resolve_target_material(
    design: &Design,
    custom: &[GemMaterial],
    combo_index: i32,
    ri_override_text: &str,
) -> ResolvedMaterial {
    let selection = target_material_selection(design, custom, combo_index, ri_override_text);
    resolved_material_from_selection(&selection, custom)
}

fn diamond_design() -> Design {
    let mut design = Design::new(
        PreformSpec::block(2.0, 1.0, 2.0),
        ScheduleMeta::default(),
        vec![ConstraintTier {
            angle_deg: -40.0,
            name: "P1".to_string(),
            indices: vec![0.0, 24.0],
            constraint: MeetConstraint::ScaleReference(0.5),
            imported_meet: None,
            original_notes: None,
            detached: Vec::new(),
        }],
    );
    design.material = MaterialSelection {
        name: Some("Diamond".to_string()),
        specific_gravity_override: None,
        refractive_index_override: None,
        body_color_override: None,
        body_color_bands_override: None,
        absorption_path_scale_override: None,
    };
    design
}

// --- resolve_target_material ---

#[test]
fn resolve_target_material_defaults_to_the_designs_own_current_material() {
    let design = diamond_design();
    let custom: [GemMaterial; 0] = [];
    let options = design_material_options(&custom);
    let own_index = design_material_index_from_name(design.material.name.as_deref(), &options);
    let target = resolve_target_material(&design, &custom, own_index, "");
    assert_eq!(target.gem.name, "Diamond");
    assert!((target.n_d - design.effective_refractive_index()).abs() < 1e-9);
}

#[test]
fn resolve_target_material_resolves_a_different_combo_selection() {
    let design = diamond_design();
    let custom: [GemMaterial; 0] = [];
    let options = design_material_options(&custom);
    let quartz_index = design_material_index_from_name(Some("Quartz"), &options);
    let target = resolve_target_material(&design, &custom, quartz_index, "");
    assert_eq!(target.gem.name, "Quartz");
    assert!((target.n_d - design.effective_refractive_index()).abs() > 0.1);
}

#[test]
fn resolve_target_material_falls_back_when_the_ri_override_text_is_invalid() {
    let design = diamond_design();
    let custom: [GemMaterial; 0] = [];
    let options = design_material_options(&custom);
    let own_index = design_material_index_from_name(design.material.name.as_deref(), &options);
    let target = resolve_target_material(&design, &custom, own_index, "not-a-number");
    assert_eq!(target.gem.name, "Diamond");
}

// --- retarget_view routing ---

#[test]
fn retarget_view_shift_mode_populates_rows_not_errors() {
    let design = diamond_design();
    let custom: [GemMaterial; 0] = [];
    let options = design_material_options(&custom);
    let quartz_index = design_material_index_from_name(Some("Quartz"), &options);
    let target = resolve_target_material(&design, &custom, quartz_index, "");
    let (view, proposal) = retarget_view(
        &design,
        &target,
        CrownShift::default(),
        RetargetMode::Shift,
        &[],
    );
    assert!(!view.rows.is_empty());
    assert_eq!(view.anchored_errors, Vec::<String>::new());
    assert_eq!(view.solve_error, "");
    assert!(proposal.is_some());
}

#[test]
fn retarget_view_optimize_mode_populates_anchored_errors_not_rows_when_anchored() {
    // `diamond_design`'s one tier is a `ScaleReference` -- always anchored, so
    // `RetargetMode::Optimize` must refuse rather than silently seed-and-stop.
    let design = diamond_design();
    let custom: [GemMaterial; 0] = [];
    let options = design_material_options(&custom);
    let quartz_index = design_material_index_from_name(Some("Quartz"), &options);
    let target = resolve_target_material(&design, &custom, quartz_index, "");
    let config = OptimizeConfig {
        max_evaluations: 4,
        ..OptimizeConfig::default()
    };
    let (view, proposal) = retarget_view(
        &design,
        &target,
        CrownShift::default(),
        RetargetMode::Optimize(config),
        &[],
    );
    assert!(view.rows.is_empty());
    assert_ne!(view.anchored_errors, Vec::<String>::new());
    assert!(view.anchored_errors[0].contains("P1"));
    assert!(proposal.is_none());
}

// --- apply_pending_retarget ---

fn fresh_state_with(design: Design) -> EditorState {
    let mut state = EditorState::fresh();
    state.design = design;
    state.history = History::new();
    state
}

#[test]
fn apply_pending_retarget_pushes_exactly_one_retarget_angles_edit_and_solves() {
    let design = diamond_design();
    let custom: [GemMaterial; 0] = [];
    let options = design_material_options(&custom);
    let quartz_index = design_material_index_from_name(Some("Quartz"), &options);
    let target = resolve_target_material(&design, &custom, quartz_index, "");
    let (_, proposal) = retarget_view(
        &design,
        &target,
        CrownShift::default(),
        RetargetMode::Shift,
        &[],
    );
    let proposal = proposal.expect("shift mode never fails");

    let mut state = fresh_state_with(design);
    let generation = state.generation.load(AtomicOrdering::Relaxed);
    let applied = apply_pending_retarget(&mut state, (proposal, generation), None, &[])
        .unwrap_or_else(|_| panic!("a fresh, matching-generation proposal must apply"));
    assert_eq!(applied, 1);
    assert!(state.history.can_undo());
    assert!(
        state.design.solve().is_ok(),
        "the retargeted design must still solve"
    );
}

#[test]
fn apply_pending_retarget_combines_a_material_change_into_one_undo_step() {
    let design = diamond_design();
    let custom: [GemMaterial; 0] = [];
    let options = design_material_options(&custom);
    let quartz_index = design_material_index_from_name(Some("Quartz"), &options);
    let target = resolve_target_material(&design, &custom, quartz_index, "");
    let (_, proposal) = retarget_view(
        &design,
        &target,
        CrownShift::default(),
        RetargetMode::Shift,
        &[],
    );
    let proposal = proposal.expect("shift mode never fails");

    let mut state = fresh_state_with(design);
    let generation = state.generation.load(AtomicOrdering::Relaxed);
    let material_change = MaterialSelection {
        name: Some("Quartz".to_string()),
        specific_gravity_override: None,
        refractive_index_override: None,
        body_color_override: None,
        body_color_bands_override: None,
        absorption_path_scale_override: None,
    };
    apply_pending_retarget(
        &mut state,
        (proposal, generation),
        Some(material_change),
        &[],
    )
    .unwrap_or_else(|_| panic!("a fresh, matching-generation proposal must apply"));
    assert_eq!(state.design.material.name.as_deref(), Some("Quartz"));

    // ONE undo step reverts both the angle retarget and the material change.
    assert!(state.undo().unwrap());
    assert_eq!(state.design.material.name.as_deref(), Some("Diamond"));
    assert!(!state.history.can_undo());
}

#[test]
fn apply_pending_retarget_commits_masts_angles_and_material_as_one_undo_step() {
    let design = diamond_design();
    let original = design.clone();
    let custom: [GemMaterial; 0] = [];
    let options = design_material_options(&custom);
    let quartz_index = design_material_index_from_name(Some("Quartz"), &options);
    let target = resolve_target_material(&design, &custom, quartz_index, "");
    let (_, proposal) = retarget_view(
        &design,
        &target,
        CrownShift::default(),
        RetargetMode::Shift,
        &[],
    );
    let proposal = proposal.expect("shift mode never fails");

    let mut state = fresh_state_with(design);
    let generation = state.generation.load(AtomicOrdering::Relaxed);
    let anchors = [AnchorChange {
        tier_index: 0,
        old_mast: 0.5,
        new_mast: 0.55,
    }];
    let material_change = MaterialSelection {
        name: Some("Quartz".to_string()),
        specific_gravity_override: None,
        refractive_index_override: None,
        body_color_override: None,
        body_color_bands_override: None,
        absorption_path_scale_override: None,
    };
    apply_pending_retarget(
        &mut state,
        (proposal, generation),
        Some(material_change),
        &anchors,
    )
    .unwrap_or_else(|_| panic!("a fresh, matching-generation proposal must apply"));
    assert!(matches!(
        state.design.tiers[0].constraint,
        MeetConstraint::ScaleReference(mast) if (mast - 0.55).abs() < 1e-12
    ));
    assert_eq!(state.design.material.name.as_deref(), Some("Quartz"));

    // The angle, the re-anchored mast and the material are ONE history entry.
    assert!(state.undo().unwrap());
    assert_eq!(state.design, original);
    assert!(!state.history.can_undo());
}

#[test]
fn apply_pending_retarget_refuses_a_stale_generation() {
    let design = diamond_design();
    let custom: [GemMaterial; 0] = [];
    let options = design_material_options(&custom);
    let quartz_index = design_material_index_from_name(Some("Quartz"), &options);
    let target = resolve_target_material(&design, &custom, quartz_index, "");
    let (_, proposal) = retarget_view(
        &design,
        &target,
        CrownShift::default(),
        RetargetMode::Shift,
        &[],
    );
    let proposal = proposal.expect("shift mode never fails");

    let mut state = fresh_state_with(design);
    let stale_generation = state.generation.load(AtomicOrdering::Relaxed) + 1;
    let result = apply_pending_retarget(&mut state, (proposal, stale_generation), None, &[]);
    assert!(matches!(result, Err(RetargetApplyError::Stale)));
    assert!(
        !state.history.can_undo(),
        "nothing should have been applied"
    );
}

// --- initial_target_index ---

#[test]
fn initial_target_index_finds_the_designs_own_named_material() {
    let custom: [GemMaterial; 0] = [];
    let options = design_material_options(&custom);
    let material = MaterialSelection {
        name: Some("Quartz".to_string()),
        specific_gravity_override: None,
        refractive_index_override: None,
        body_color_override: None,
        body_color_bands_override: None,
        absorption_path_scale_override: None,
    };
    let quartz_index = design_material_index_from_name(Some("Quartz"), &options);
    assert_eq!(initial_target_index(&material, &options), quartz_index);
}

#[test]
fn initial_target_index_seeds_the_custom_ri_sentinel_for_a_nameless_override() {
    let custom: [GemMaterial; 0] = [];
    let options = design_material_options(&custom);
    let material = MaterialSelection {
        name: None,
        specific_gravity_override: None,
        refractive_index_override: Some(1.6),
        body_color_override: None,
        body_color_bands_override: None,
        absorption_path_scale_override: None,
    };
    assert_eq!(
        initial_target_index(&material, &options),
        i32::try_from(options.len()).unwrap() - 1
    );
    assert_eq!(
        options.last().map(String::as_str),
        Some("Custom RI\u{2026}")
    );
}

#[test]
fn initial_target_index_falls_back_to_none_for_a_plain_nameless_material() {
    let custom: [GemMaterial; 0] = [];
    let options = design_material_options(&custom);
    let material = MaterialSelection::default();
    assert_eq!(initial_target_index(&material, &options), 0);
}

// --- target_material_selection ---

#[test]
fn target_material_selection_falls_back_to_the_current_material_on_unparseable_ri() {
    let design = diamond_design();
    let custom: [GemMaterial; 0] = [];
    let selection = target_material_selection(&design, &custom, 0, "not-a-number");
    assert_eq!(selection, design.material);
}

// --- resolve_target_selection ---

#[test]
fn resolve_target_selection_reports_an_unparseable_ri_override_instead_of_falling_back() {
    let design = diamond_design();
    let custom: [GemMaterial; 0] = [];
    let err = resolve_target_selection(&design, &custom, 0, "1,74")
        .expect_err("a comma-separated RI override must not silently parse");
    assert!(
        err.contains("1,74"),
        "error should name the bad text: {err}"
    );
}

#[test]
fn resolve_target_selection_reports_a_non_positive_ri_override() {
    let design = diamond_design();
    let custom: [GemMaterial; 0] = [];
    let err = resolve_target_selection(&design, &custom, 0, "0.5")
        .expect_err("an RI override of 0.5 is not physically valid");
    assert!(err.contains("greater than 1.0"), "got: {err}");
}

#[test]
fn resolve_target_selection_accepts_a_valid_ri_override() {
    let design = diamond_design();
    let custom: [GemMaterial; 0] = [];
    let selection = resolve_target_selection(&design, &custom, 0, "1.74")
        .expect("a well-formed RI override must parse");
    assert_eq!(selection.refractive_index_override, Some(1.74));
}

// --- target_display_name ---

#[test]
fn target_display_name_shows_none_for_a_nameless_uncustomized_selection() {
    let selection = MaterialSelection::default();
    assert_eq!(target_display_name(&selection), "(none)");
}

#[test]
fn target_display_name_shows_custom_ri_for_a_nameless_override() {
    let selection = MaterialSelection {
        name: None,
        specific_gravity_override: None,
        refractive_index_override: Some(1.74),
        body_color_override: None,
        body_color_bands_override: None,
        absorption_path_scale_override: None,
    };
    assert_eq!(target_display_name(&selection), "Custom RI");
}

#[test]
fn target_display_name_shows_the_picked_material_name() {
    let selection = MaterialSelection {
        name: Some("Quartz".to_string()),
        specific_gravity_override: None,
        refractive_index_override: None,
        body_color_override: None,
        body_color_bands_override: None,
        absorption_path_scale_override: None,
    };
    assert_eq!(target_display_name(&selection), "Quartz");
}

// --- diff_row_view / diff_rows_from_deltas ---

fn tier_for_diff(name: &str, angle_deg: f64) -> ConstraintTier {
    ConstraintTier {
        angle_deg,
        name: name.to_string(),
        indices: vec![0.0],
        constraint: MeetConstraint::ScaleReference(0.5),
        imported_meet: None,
        original_notes: None,
        detached: Vec::new(),
    }
}

#[test]
fn diff_row_view_labels_an_unchanged_position_same() {
    let before = vec![tier_for_diff("Table", 0.0)];
    let after = before.clone();
    let deltas = diff_tiers(&before, None, &after, None);
    let row = diff_row_view(&deltas[0]);
    assert_eq!(row.status_label, "Same");
    assert_eq!(row.mast_delta, "-");
}

#[test]
fn diff_row_view_labels_a_moved_angle_changed() {
    let before = vec![tier_for_diff("Star", 15.0)];
    let mut after = before.clone();
    after[0].angle_deg = 16.0;
    let deltas = diff_tiers(&before, None, &after, None);
    let row = diff_row_view(&deltas[0]);
    assert_eq!(row.status_label, "Changed");
    assert_eq!(row.old_angle, "15.00\u{b0}");
    assert_eq!(row.new_angle, "16.00\u{b0}");
}

#[test]
fn diff_row_view_reports_a_signed_mast_delta_when_both_masts_are_known() {
    use indicatrix::geometry::meet_solver::{SolveStrategy, SolvedTier};
    let before = vec![tier_for_diff("Table", 0.0)];
    let after = before.clone();
    let before_solved = vec![SolvedTier {
        mast: 0.5,
        strategy: SolveStrategy::ScaleReference,
        detail: String::new(),
    }];
    let after_solved = vec![SolvedTier {
        mast: 0.55,
        strategy: SolveStrategy::ScaleReference,
        detail: String::new(),
    }];
    let deltas = diff_tiers(&before, Some(&before_solved), &after, Some(&after_solved));
    let row = diff_row_view(&deltas[0]);
    assert_eq!(row.mast_delta, "+0.0500");
}

#[test]
fn diff_row_view_labels_added_and_removed_positions() {
    let before = vec![tier_for_diff("Table", 0.0)];
    let after = vec![tier_for_diff("Table", 0.0), tier_for_diff("Star", 15.0)];
    let deltas = diff_tiers(&before, None, &after, None);
    assert_eq!(diff_row_view(&deltas[0]).status_label, "Same");
    assert_eq!(diff_row_view(&deltas[1]).status_label, "Added");

    let deltas_reverse = diff_tiers(&after, None, &before, None);
    assert_eq!(diff_row_view(&deltas_reverse[1]).status_label, "Removed");
}

#[test]
fn diff_rows_from_deltas_carries_the_tier_index_and_name_through() {
    let before = vec![tier_for_diff("Table", 0.0), tier_for_diff("Star", 15.0)];
    let mut after = before.clone();
    after[1].angle_deg = 16.0;
    let deltas = diff_tiers(&before, None, &after, None);
    let rows = diff_rows_from_deltas(&deltas);
    assert_eq!(rows.len(), 2);
    assert_eq!(rows[1].tier_index, 1);
    assert_eq!(rows[1].name.as_str(), "Star");
    assert_eq!(rows[1].risk_label.as_str(), "Changed");
}

// --- The Optimize candidate list ---

fn candidate_with(kind: CandidateKind, score: f32) -> SearchCandidate {
    let mut validity = RetargetValidity::unchecked(&InvalidReason::NotClosed);
    validity.status = ValidityStatus::Valid;
    validity.reasons.clear();
    SearchCandidate {
        kind,
        angles: Vec::new(),
        anchors: Vec::new(),
        validity,
        metrics: RetargetMetrics::default(),
        numbers: CandidateNumbers {
            score,
            windowing_pct: 4.5,
            brilliance_pct: 81.0,
            extinction_pct: 3.0,
            yield_loss_pct: 40.5,
        },
        design: diamond_design(),
    }
}

fn report_with(candidates: Vec<SearchCandidate>, evaluations: usize) -> SearchReport {
    SearchReport {
        start: StartPoint::Shift,
        shift_validity: RetargetValidity::unchecked(&InvalidReason::NotClosed),
        start_numbers: CandidateNumbers {
            score: 10.0,
            windowing_pct: 5.0,
            brilliance_pct: 80.0,
            extinction_pct: 3.0,
            yield_loss_pct: 40.0,
        },
        candidates,
        dropped: Vec::new(),
        evaluations,
        free_tiers: 4,
        keep_look: false,
    }
}

#[test]
fn the_candidate_list_numbers_the_options_and_says_where_each_came_from() {
    let rows = candidate_row_views(&[
        candidate_with(CandidateKind::Optimized, 8.0),
        candidate_with(CandidateKind::Shift, 9.5),
        candidate_with(CandidateKind::Partial { percent: 40 }, 11.0),
    ]);
    assert_eq!(
        rows.iter().map(|row| row.rank).collect::<Vec<_>>(),
        vec![1, 2, 3]
    );
    assert_eq!(rows[0].label, "Searched angles");
    assert_eq!(rows[1].label, "Shift result");
    assert_eq!(rows[2].label, "Part of the Shift change (40 %)");
    assert_eq!(rows[0].score, "8.0");
    assert_eq!(rows[0].windowing, "4.5 %");
    assert_eq!(rows[0].brilliance, "81.0 %");
    assert_eq!(rows[0].extinction, "3.0 %");
    assert_eq!(rows[0].yield_loss, "40.5 %");
    assert!(rows.iter().all(|row| row.verdict == "Valid"));
}

#[test]
fn an_option_that_is_not_valid_is_not_called_valid() {
    let mut candidate = candidate_with(CandidateKind::Optimized, 8.0);
    candidate.validity.status = ValidityStatus::Invalid;
    let rows = candidate_row_views(&[candidate]);
    assert_eq!(rows[0].verdict, "Not valid");
}

#[test]
fn the_search_summary_counts_the_options_and_the_steps() {
    let two = report_with(
        vec![
            candidate_with(CandidateKind::Optimized, 8.0),
            candidate_with(CandidateKind::Shift, 9.5),
        ],
        120,
    );
    assert_eq!(
        search_summary_line(&two),
        "2 valid options, best score first (lower is better). The search used 120 steps."
    );
    let one = report_with(vec![candidate_with(CandidateKind::Shift, 9.5)], 40);
    assert!(search_summary_line(&one).starts_with("1 valid option, "));
    assert_eq!(
        search_summary_line(&report_with(Vec::new(), 40)),
        "No valid option was found."
    );
}

#[test]
fn the_original_snapshot_label_names_the_target_and_is_told_from_a_users_own() {
    use super::snapshot::original_snapshot_label;
    let label = original_snapshot_label("Sapphire");
    assert!(label.contains("Sapphire"));
}

#[test]
fn the_original_snapshot_solve_prefers_the_cached_one_then_solves_never_a_wrong_length() {
    use super::apply::original_solve_for_snapshot;
    let session = indicatrix_editor::EditorSession::from_template(
        indicatrix_cut_core::FreshDesignSpec {
            gear_teeth: 96,
            symmetry_order: 8,
            mirror: true,
            material: indicatrix_cut_core::MaterialSelection::none(),
            preform: indicatrix_cut_core::PreformSpec::cylinder(96, 1.5, 1.0, 1.5),
        },
        1,
    );
    let design = session.design;
    let solved = design.solve().expect("the fresh template solves");
    // A matching cached solve is used as is.
    let kept = original_solve_for_snapshot(Some(solved.clone()), &design).expect("cached");
    assert_eq!(kept.len(), design.tiers.len());
    // A cached solve of another design (wrong tier count) is dropped and the design solved.
    let mut wrong = solved;
    wrong.pop();
    let fresh = original_solve_for_snapshot(Some(wrong), &design).expect("solved on the spot");
    assert_eq!(fresh.len(), design.tiers.len());
    // No cache: solved on the spot.
    assert!(original_solve_for_snapshot(None, &design).is_some());
}