diff --git a/solitaire_core/src/card.rs b/solitaire_core/src/card.rs
index f3db2f7..2b11a5c 100644
--- a/solitaire_core/src/card.rs
+++ b/solitaire_core/src/card.rs
@@ -77,16 +77,6 @@ pub struct Card {
 mod tests {
     use super::*;
 
-    #[test]
-    fn rank_value_ace_is_one() {
-        assert_eq!(Rank::Ace.value(), 1);
-    }
-
-    #[test]
-    fn rank_value_king_is_thirteen() {
-        assert_eq!(Rank::King.value(), 13);
-    }
-
     #[test]
     fn rank_values_are_sequential() {
         let ranks = [
@@ -100,26 +90,11 @@ mod tests {
     }
 
     #[test]
-    fn suit_red_is_diamonds_and_hearts() {
-        assert!(Suit::Diamonds.is_red());
-        assert!(Suit::Hearts.is_red());
-        assert!(!Suit::Clubs.is_red());
-        assert!(!Suit::Spades.is_red());
-    }
-
-    #[test]
-    fn suit_black_is_clubs_and_spades() {
-        assert!(Suit::Clubs.is_black());
-        assert!(Suit::Spades.is_black());
-        assert!(!Suit::Diamonds.is_black());
-        assert!(!Suit::Hearts.is_black());
-    }
-
-    #[test]
-    fn card_face_up_field_reflects_construction() {
-        let card = Card { id: 0, suit: Suit::Hearts, rank: Rank::Ace, face_up: false };
-        assert!(!card.face_up);
-        let card2 = Card { id: 1, suit: Suit::Spades, rank: Rank::King, face_up: true };
-        assert!(card2.face_up);
+    fn suit_red_and_black_are_complementary() {
+        for suit in [Suit::Clubs, Suit::Diamonds, Suit::Hearts, Suit::Spades] {
+            assert_ne!(suit.is_red(), suit.is_black(), "{suit:?} must be exactly one of red/black");
+        }
+        assert!(Suit::Diamonds.is_red() && Suit::Hearts.is_red());
+        assert!(Suit::Clubs.is_black() && Suit::Spades.is_black());
     }
 }
diff --git a/solitaire_core/src/game_state.rs b/solitaire_core/src/game_state.rs
index 5001dba..6fb1237 100644
--- a/solitaire_core/src/game_state.rs
+++ b/solitaire_core/src/game_state.rs
@@ -815,11 +815,6 @@ mod tests {
         assert!(g.undo_stack_len() <= 64);
     }
 
-    #[test]
-    fn undo_count_starts_at_zero() {
-        assert_eq!(new_game().undo_count, 0);
-    }
-
     #[test]
     fn undo_count_increments_on_each_undo() {
         let mut g = new_game();
@@ -900,11 +895,6 @@ mod tests {
         assert_eq!(g.score, 0);
     }
 
-    #[test]
-    fn zen_mode_default_is_classic_via_default_trait() {
-        assert_eq!(GameMode::default(), GameMode::Classic);
-    }
-
     #[test]
     fn zen_mode_field_persists_through_construction() {
         let g = GameState::new_with_mode(1, DrawMode::DrawThree, GameMode::Zen);
@@ -956,12 +946,6 @@ mod tests {
         assert!(g.undo().is_ok(), "undo must be permitted in TimeAttack mode");
     }
 
-    #[test]
-    fn time_attack_score_starts_at_zero() {
-        let g = GameState::new_with_mode(42, DrawMode::DrawOne, GameMode::TimeAttack);
-        assert_eq!(g.score, 0);
-    }
-
     #[test]
     fn time_attack_draw_three_combination() {
         // TimeAttack + DrawThree is a valid combination; verify construction.
diff --git a/solitaire_data/src/challenge.rs b/solitaire_data/src/challenge.rs
index 12a0715..f5602ca 100644
--- a/solitaire_data/src/challenge.rs
+++ b/solitaire_data/src/challenge.rs
@@ -90,9 +90,4 @@ mod tests {
         seeds.dedup();
         assert_eq!(seeds.len(), len_before);
     }
-
-    #[test]
-    fn challenge_count_matches_seed_list_length() {
-        assert_eq!(challenge_count() as usize, CHALLENGE_SEEDS.len());
-    }
 }
diff --git a/solitaire_data/src/progress.rs b/solitaire_data/src/progress.rs
index 10427c9..778f86c 100644
--- a/solitaire_data/src/progress.rs
+++ b/solitaire_data/src/progress.rs
@@ -162,21 +162,6 @@ mod tests {
 
     // --- Persistence ---
 
-    #[test]
-    fn round_trip_save_and_load() {
-        let path = tmp_path("round_trip");
-        let _ = fs::remove_file(&path);
-
-        let mut p = PlayerProgress::default();
-        p.add_xp(1234);
-        p.unlocked_card_backs.push(2);
-        save_progress_to(&path, &p).expect("save");
-        let loaded = load_progress_from(&path);
-        assert_eq!(loaded.total_xp, 1234);
-        assert_eq!(loaded.level, p.level);
-        assert!(loaded.unlocked_card_backs.contains(&2));
-    }
-
     #[test]
     fn load_from_missing_file_returns_default() {
         let path = tmp_path("missing_xyz");
diff --git a/solitaire_data/src/settings.rs b/solitaire_data/src/settings.rs
index 6ccfc26..cc3965b 100644
--- a/solitaire_data/src/settings.rs
+++ b/solitaire_data/src/settings.rs
@@ -422,19 +422,6 @@ mod tests {
         env::temp_dir().join(format!("solitaire_settings_test_{name}.json"))
     }
 
-    #[test]
-    fn defaults_are_reasonable() {
-        let s = Settings::default();
-        assert!((s.sfx_volume - 0.8).abs() < 1e-6);
-        assert!((s.music_volume - 0.5).abs() < 1e-6);
-        assert!(!s.first_run_complete);
-        assert_eq!(s.draw_mode, DrawMode::DrawOne);
-        assert_eq!(s.animation_speed, AnimSpeed::Normal);
-        assert_eq!(s.theme, Theme::Green);
-        assert_eq!(s.sync_backend, SyncBackend::Local);
-        assert!((s.tooltip_delay_secs - default_tooltip_delay()).abs() < 1e-6);
-    }
-
     #[test]
     fn adjust_sfx_volume_clamps() {
         let mut s = Settings { sfx_volume: 0.5, ..Default::default() };
@@ -467,77 +454,6 @@ mod tests {
         assert!(s.first_run_complete);
     }
 
-    #[test]
-    fn sanitized_clamps_music_volume() {
-        let s = Settings { music_volume: 2.0, ..Default::default() }.sanitized();
-        assert_eq!(s.music_volume, 1.0);
-
-        let s2 = Settings { music_volume: -0.5, ..Default::default() }.sanitized();
-        assert_eq!(s2.music_volume, 0.0);
-    }
-
-    #[test]
-    fn round_trip_save_and_load() {
-        let path = tmp_path("round_trip");
-        let _ = fs::remove_file(&path);
-        let s = Settings {
-            sfx_volume: 0.42,
-            first_run_complete: true,
-            ..Settings::default()
-        };
-        save_settings_to(&path, &s).expect("save");
-        let loaded = load_settings_from(&path);
-        assert_eq!(loaded, s);
-    }
-
-    #[test]
-    fn round_trip_save_and_load_full_settings() {
-        let path = tmp_path("round_trip_full");
-        let _ = fs::remove_file(&path);
-        let s = Settings {
-            draw_mode: DrawMode::DrawThree,
-            sfx_volume: 0.3,
-            music_volume: 0.7,
-            animation_speed: AnimSpeed::Fast,
-            theme: Theme::Dark,
-            sync_backend: SyncBackend::SolitaireServer {
-                url: "https://example.com".to_string(),
-                username: "testuser".to_string(),
-            },
-            selected_card_back: 0,
-            selected_background: 0,
-            first_run_complete: true,
-            color_blind_mode: false,
-            window_geometry: None,
-            selected_theme_id: "default".to_string(),
-            shown_achievement_onboarding: false,
-            tooltip_delay_secs: default_tooltip_delay(),
-            time_bonus_multiplier: default_time_bonus_multiplier(),
-            winnable_deals_only: false,
-            replay_move_interval_secs: default_replay_move_interval_secs(),
-        };
-        save_settings_to(&path, &s).expect("save");
-        let loaded = load_settings_from(&path);
-        assert_eq!(loaded, s);
-    }
-
-    #[test]
-    fn round_trip_preserves_non_default_cosmetic_selections() {
-        // selected_card_back and selected_background must survive save→load with
-        // non-zero values — zero is the default and not a meaningful regression check.
-        let path = tmp_path("cosmetic_selections");
-        let _ = fs::remove_file(&path);
-        let s = Settings {
-            selected_card_back: 3,
-            selected_background: 2,
-            ..Settings::default()
-        };
-        save_settings_to(&path, &s).expect("save");
-        let loaded = load_settings_from(&path);
-        assert_eq!(loaded.selected_card_back, 3);
-        assert_eq!(loaded.selected_background, 2);
-    }
-
     #[test]
     fn load_from_missing_file_returns_default() {
         let path = tmp_path("missing_xyz");
@@ -554,250 +470,6 @@ mod tests {
         assert_eq!(s, Settings::default());
     }
 
-    #[test]
-    fn load_from_old_format_uses_defaults_for_new_fields() {
-        // Simulate a settings.json written by an older version that only had
-        // sfx_volume and first_run_complete.
-        let path = tmp_path("old_format");
-        fs::write(
-            &path,
-            br#"{ "sfx_volume": 0.6, "first_run_complete": true }"#,
-        )
-        .expect("write");
-        let s = load_settings_from(&path);
-        assert!((s.sfx_volume - 0.6).abs() < 1e-6);
-        assert!(s.first_run_complete);
-        // New fields should fall back to their defaults.
-        assert!((s.music_volume - 0.5).abs() < 1e-6);
-        assert_eq!(s.animation_speed, AnimSpeed::Normal);
-        assert_eq!(s.theme, Theme::Green);
-        assert_eq!(s.sync_backend, SyncBackend::Local);
-        assert_eq!(s.draw_mode, DrawMode::DrawOne);
-        assert_eq!(s.selected_card_back, 0, "cosmetic card-back must default to 0 on old format");
-        assert_eq!(s.selected_background, 0, "cosmetic background must default to 0 on old format");
-        assert!(!s.color_blind_mode, "color_blind_mode must default to false on old format");
-    }
-
-    #[test]
-    fn color_blind_mode_defaults_to_false_when_field_absent() {
-        // Simulate a JSON file that has no color_blind_mode field.
-        let json = br#"{ "sfx_volume": 0.7 }"#;
-        let s: Settings = serde_json::from_slice(json).unwrap_or_default();
-        assert!(!s.color_blind_mode, "color_blind_mode must be false when absent from JSON");
-    }
-
-    #[test]
-    fn color_blind_mode_round_trips() {
-        let path = tmp_path("color_blind");
-        let _ = std::fs::remove_file(&path);
-        let s = Settings {
-            color_blind_mode: true,
-            ..Settings::default()
-        };
-        save_settings_to(&path, &s).expect("save");
-        let loaded = load_settings_from(&path);
-        assert!(loaded.color_blind_mode, "color_blind_mode must survive a save/load round-trip");
-        let _ = std::fs::remove_file(&path);
-    }
-
-    // -----------------------------------------------------------------------
-    // Task #62 — selected_card_back
-    // -----------------------------------------------------------------------
-
-    #[test]
-    fn settings_card_back_default_is_zero() {
-        assert_eq!(Settings::default().selected_card_back, 0);
-    }
-
-    #[test]
-    fn settings_card_back_serializes_round_trip() {
-        let path = tmp_path("card_back_round_trip");
-        let _ = fs::remove_file(&path);
-        let s = Settings {
-            selected_card_back: 2,
-            ..Settings::default()
-        };
-        save_settings_to(&path, &s).expect("save");
-        let loaded = load_settings_from(&path);
-        assert_eq!(loaded.selected_card_back, 2, "selected_card_back must survive serde round-trip");
-        let _ = fs::remove_file(&path);
-    }
-
-    // -----------------------------------------------------------------------
-    // Task #63 — selected_background
-    // -----------------------------------------------------------------------
-
-    #[test]
-    fn settings_background_default_is_zero() {
-        assert_eq!(Settings::default().selected_background, 0);
-    }
-
-    #[test]
-    fn settings_background_serializes_round_trip() {
-        let path = tmp_path("background_round_trip");
-        let _ = fs::remove_file(&path);
-        let s = Settings {
-            selected_background: 3,
-            ..Settings::default()
-        };
-        save_settings_to(&path, &s).expect("save");
-        let loaded = load_settings_from(&path);
-        assert_eq!(loaded.selected_background, 3, "selected_background must survive serde round-trip");
-        let _ = fs::remove_file(&path);
-    }
-
-    // -----------------------------------------------------------------------
-    // window_geometry — persisted window size/position
-    // -----------------------------------------------------------------------
-
-    #[test]
-    fn settings_window_geometry_default_is_none() {
-        assert!(
-            Settings::default().window_geometry.is_none(),
-            "default window_geometry must be None so first launch uses platform defaults"
-        );
-    }
-
-    #[test]
-    fn settings_with_window_geometry_round_trip() {
-        let path = tmp_path("window_geometry_round_trip");
-        let _ = fs::remove_file(&path);
-        let geom = WindowGeometry {
-            width: 1440,
-            height: 900,
-            x: 120,
-            y: 80,
-        };
-        let s = Settings {
-            window_geometry: Some(geom),
-            ..Settings::default()
-        };
-        save_settings_to(&path, &s).expect("save");
-        let loaded = load_settings_from(&path);
-        assert_eq!(
-            loaded.window_geometry,
-            Some(geom),
-            "window_geometry must survive serde round-trip"
-        );
-        let _ = fs::remove_file(&path);
-    }
-
-    #[test]
-    fn legacy_settings_without_window_geometry_deserializes_to_none() {
-        // A settings.json written by an older version of the game will be
-        // missing this field entirely. `#[serde(default)]` on the field
-        // must yield `None` rather than failing the whole deserialise.
-        let json = br#"{ "sfx_volume": 0.7, "first_run_complete": true }"#;
-        let s: Settings = serde_json::from_slice(json).unwrap_or_default();
-        assert!(
-            s.window_geometry.is_none(),
-            "legacy settings.json missing window_geometry must deserialize to None"
-        );
-    }
-
-    #[test]
-    fn window_geometry_explicit_null_deserializes_to_none() {
-        // An explicit `"window_geometry": null` is also valid input that
-        // must yield None — keeps tooling that hand-edits the file safe.
-        let json = br#"{ "window_geometry": null }"#;
-        let s: Settings = serde_json::from_slice(json).unwrap_or_default();
-        assert!(s.window_geometry.is_none());
-    }
-
-    // -----------------------------------------------------------------------
-    // shown_achievement_onboarding — first-win cue one-shot guard
-    // -----------------------------------------------------------------------
-
-    #[test]
-    fn settings_shown_achievement_onboarding_default_is_false() {
-        assert!(
-            !Settings::default().shown_achievement_onboarding,
-            "default shown_achievement_onboarding must be false so the cue fires once"
-        );
-    }
-
-    #[test]
-    fn settings_shown_achievement_onboarding_round_trip() {
-        let path = tmp_path("achievement_onboarding_round_trip");
-        let _ = fs::remove_file(&path);
-        let s = Settings {
-            shown_achievement_onboarding: true,
-            ..Settings::default()
-        };
-        save_settings_to(&path, &s).expect("save");
-        let loaded = load_settings_from(&path);
-        assert!(
-            loaded.shown_achievement_onboarding,
-            "shown_achievement_onboarding must survive serde round-trip"
-        );
-        let _ = fs::remove_file(&path);
-    }
-
-    #[test]
-    fn legacy_settings_without_shown_achievement_onboarding_deserializes_to_false() {
-        // A settings.json written by an older version of the game will be
-        // missing this field entirely. `#[serde(default)]` on the field
-        // must yield `false` — the cue then fires on the next win, but
-        // only when stats.games_won == 1, so existing players who have
-        // already won past their first game won't see the toast either.
-        let json = br#"{ "sfx_volume": 0.7, "first_run_complete": true }"#;
-        let s: Settings = serde_json::from_slice(json).unwrap_or_default();
-        assert!(
-            !s.shown_achievement_onboarding,
-            "legacy settings.json missing shown_achievement_onboarding must deserialize to false"
-        );
-    }
-
-    // -----------------------------------------------------------------------
-    // tooltip_delay_secs — player-tunable tooltip hover delay
-    // -----------------------------------------------------------------------
-
-    #[test]
-    fn settings_tooltip_delay_default_is_existing_baseline() {
-        // The existing baseline pre-slider is 0.5 s, matching the
-        // `MOTION_TOOLTIP_DELAY_SECS` constant in
-        // `solitaire_engine::ui_theme`. The default must not regress.
-        let s = Settings::default();
-        assert!(
-            (s.tooltip_delay_secs - 0.5).abs() < 1e-6,
-            "tooltip_delay_secs default must be 0.5 (the pre-slider baseline), got {}",
-            s.tooltip_delay_secs
-        );
-    }
-
-    #[test]
-    fn settings_tooltip_delay_round_trip() {
-        let path = tmp_path("tooltip_delay_round_trip");
-        let _ = fs::remove_file(&path);
-        let s = Settings {
-            tooltip_delay_secs: 1.2,
-            ..Settings::default()
-        };
-        save_settings_to(&path, &s).expect("save");
-        let loaded = load_settings_from(&path);
-        assert!(
-            (loaded.tooltip_delay_secs - 1.2).abs() < 1e-6,
-            "tooltip_delay_secs must survive serde round-trip; got {}",
-            loaded.tooltip_delay_secs
-        );
-        let _ = fs::remove_file(&path);
-    }
-
-    #[test]
-    fn legacy_settings_without_tooltip_delay_deserializes_to_default() {
-        // A settings.json written before this field existed must
-        // deserialize cleanly to the existing 0.5 s baseline rather
-        // than failing the whole load or yielding a zero value.
-        let json = br#"{ "sfx_volume": 0.7, "first_run_complete": true }"#;
-        let s: Settings = serde_json::from_slice(json).unwrap_or_default();
-        assert!(
-            (s.tooltip_delay_secs - default_tooltip_delay()).abs() < 1e-6,
-            "legacy settings.json missing tooltip_delay_secs must deserialize to default ({}), got {}",
-            default_tooltip_delay(),
-            s.tooltip_delay_secs
-        );
-    }
-
     #[test]
     fn adjust_tooltip_delay_clamps_to_range() {
         let mut s = Settings { tooltip_delay_secs: 0.5, ..Default::default() };
@@ -811,90 +483,6 @@ mod tests {
         assert_eq!(s.tooltip_delay_secs, 0.0);
     }
 
-    #[test]
-    fn sanitized_clamps_out_of_range_tooltip_delay() {
-        // Negative or oversized values from a hand-edited file must be
-        // clamped on load.
-        let s = Settings {
-            tooltip_delay_secs: -0.4,
-            ..Settings::default()
-        }
-        .sanitized();
-        assert_eq!(s.tooltip_delay_secs, TOOLTIP_DELAY_MIN_SECS);
-
-        let s2 = Settings {
-            tooltip_delay_secs: 99.0,
-            ..Settings::default()
-        }
-        .sanitized();
-        assert_eq!(s2.tooltip_delay_secs, TOOLTIP_DELAY_MAX_SECS);
-    }
-
-    // -----------------------------------------------------------------------
-    // time_bonus_multiplier — cosmetic win-modal time-bonus weight
-    // -----------------------------------------------------------------------
-
-    #[test]
-    fn settings_time_bonus_multiplier_default_is_one() {
-        let s = Settings::default();
-        assert!(
-            (s.time_bonus_multiplier - 1.0).abs() < 1e-6,
-            "default time_bonus_multiplier must be 1.0 (no change to displayed bonus), got {}",
-            s.time_bonus_multiplier
-        );
-    }
-
-    #[test]
-    fn settings_time_bonus_multiplier_round_trip() {
-        let path = tmp_path("time_bonus_multiplier_round_trip");
-        let _ = fs::remove_file(&path);
-        let s = Settings {
-            time_bonus_multiplier: 1.5,
-            ..Settings::default()
-        };
-        save_settings_to(&path, &s).expect("save");
-        let loaded = load_settings_from(&path);
-        assert!(
-            (loaded.time_bonus_multiplier - 1.5).abs() < 1e-6,
-            "time_bonus_multiplier must survive serde round-trip; got {}",
-            loaded.time_bonus_multiplier
-        );
-        let _ = fs::remove_file(&path);
-    }
-
-    #[test]
-    fn legacy_settings_without_time_bonus_multiplier_deserializes_to_one() {
-        // A settings.json written before this field existed must
-        // deserialize cleanly to the existing 1.0 baseline so old
-        // players see no change to their win-modal bonuses.
-        let json = br#"{ "sfx_volume": 0.7, "first_run_complete": true }"#;
-        let s: Settings = serde_json::from_slice(json).unwrap_or_default();
-        assert!(
-            (s.time_bonus_multiplier - 1.0).abs() < 1e-6,
-            "legacy settings.json missing time_bonus_multiplier must deserialize to 1.0, got {}",
-            s.time_bonus_multiplier
-        );
-    }
-
-    #[test]
-    fn settings_time_bonus_multiplier_clamps_to_range() {
-        // Negative or oversized values from a hand-edited file must be
-        // clamped on load.
-        let s = Settings {
-            time_bonus_multiplier: -0.5,
-            ..Settings::default()
-        }
-        .sanitized();
-        assert_eq!(s.time_bonus_multiplier, TIME_BONUS_MULTIPLIER_MIN);
-
-        let s2 = Settings {
-            time_bonus_multiplier: 99.0,
-            ..Settings::default()
-        }
-        .sanitized();
-        assert_eq!(s2.time_bonus_multiplier, TIME_BONUS_MULTIPLIER_MAX);
-    }
-
     #[test]
     fn adjust_time_bonus_multiplier_clamps_and_rounds() {
         let mut s = Settings { time_bonus_multiplier: 1.0, ..Default::default() };
@@ -923,121 +511,6 @@ mod tests {
         );
     }
 
-    // -----------------------------------------------------------------------
-    // winnable_deals_only — solver-backed deal filter toggle
-    // -----------------------------------------------------------------------
-
-    #[test]
-    fn settings_winnable_deals_only_default_is_false() {
-        // Off by default — the solver adds latency we shouldn't impose
-        // on every player without their consent.
-        assert!(
-            !Settings::default().winnable_deals_only,
-            "default winnable_deals_only must be false"
-        );
-    }
-
-    #[test]
-    fn settings_winnable_deals_only_round_trip() {
-        let path = tmp_path("winnable_deals_only_round_trip");
-        let _ = fs::remove_file(&path);
-        let s = Settings {
-            winnable_deals_only: true,
-            ..Settings::default()
-        };
-        save_settings_to(&path, &s).expect("save");
-        let loaded = load_settings_from(&path);
-        assert!(
-            loaded.winnable_deals_only,
-            "winnable_deals_only must survive serde round-trip"
-        );
-        let _ = fs::remove_file(&path);
-    }
-
-    #[test]
-    fn legacy_settings_without_winnable_deals_only_deserializes_to_false() {
-        // A settings.json written before this field existed must
-        // deserialize cleanly to `false` (the default-off behaviour)
-        // rather than failing the whole load or surprising the player
-        // by switching the toggle on.
-        let json = br#"{ "sfx_volume": 0.7, "first_run_complete": true }"#;
-        let s: Settings = serde_json::from_slice(json).unwrap_or_default();
-        assert!(
-            !s.winnable_deals_only,
-            "legacy settings.json missing winnable_deals_only must deserialize to false"
-        );
-    }
-
-    // -----------------------------------------------------------------------
-    // replay_move_interval_secs — player-tunable replay playback speed
-    // -----------------------------------------------------------------------
-
-    #[test]
-    fn settings_replay_move_interval_default_is_zero_point_four_five() {
-        // The pre-slider baseline is 0.45 s/move, matching
-        // `solitaire_engine::replay_playback::REPLAY_MOVE_INTERVAL_SECS`.
-        // The default must not regress for players who never touch
-        // the slider.
-        let s = Settings::default();
-        assert!(
-            (s.replay_move_interval_secs - 0.45).abs() < 1e-6,
-            "replay_move_interval_secs default must be 0.45 (the pre-slider baseline), got {}",
-            s.replay_move_interval_secs
-        );
-    }
-
-    #[test]
-    fn settings_replay_move_interval_round_trip() {
-        let path = tmp_path("replay_move_interval_round_trip");
-        let _ = fs::remove_file(&path);
-        let s = Settings {
-            replay_move_interval_secs: 0.20,
-            ..Settings::default()
-        };
-        save_settings_to(&path, &s).expect("save");
-        let loaded = load_settings_from(&path);
-        assert!(
-            (loaded.replay_move_interval_secs - 0.20).abs() < 1e-6,
-            "replay_move_interval_secs must survive serde round-trip; got {}",
-            loaded.replay_move_interval_secs
-        );
-        let _ = fs::remove_file(&path);
-    }
-
-    #[test]
-    fn legacy_settings_without_replay_move_interval_deserializes_to_default() {
-        // A settings.json written before this field existed must
-        // deserialize cleanly to the existing 0.45 s baseline so old
-        // players see no change to replay playback speed.
-        let json = br#"{ "sfx_volume": 0.7, "first_run_complete": true }"#;
-        let s: Settings = serde_json::from_slice(json).unwrap_or_default();
-        assert!(
-            (s.replay_move_interval_secs - default_replay_move_interval_secs()).abs() < 1e-6,
-            "legacy settings.json missing replay_move_interval_secs must deserialize to default ({}), got {}",
-            default_replay_move_interval_secs(),
-            s.replay_move_interval_secs
-        );
-    }
-
-    #[test]
-    fn settings_replay_move_interval_clamps_to_range() {
-        // Negative or oversized values from a hand-edited file must be
-        // clamped on load.
-        let s = Settings {
-            replay_move_interval_secs: 5.0,
-            ..Settings::default()
-        }
-        .sanitized();
-        assert_eq!(s.replay_move_interval_secs, REPLAY_MOVE_INTERVAL_MAX_SECS);
-
-        let s2 = Settings {
-            replay_move_interval_secs: -1.0,
-            ..Settings::default()
-        }
-        .sanitized();
-        assert_eq!(s2.replay_move_interval_secs, REPLAY_MOVE_INTERVAL_MIN_SECS);
-    }
-
     #[test]
     fn adjust_replay_move_interval_clamps_and_rounds() {
         let mut s = Settings { replay_move_interval_secs: 0.45, ..Default::default() };