Extracted functionality for clearing out dead worms

2 files changed, 157 insertions, 27 deletions

diff --git a/src/game.rs b/src/game.rs
index 1d9d33b..5ddbdfd 100644
--- a/src/game.rs
+++ b/src/game.rs
@@ -111,18 +111,7 @@ impl GameBoard {
         
         // Remove dead worms and update active worm
         for player in &mut self.players {
-            for worm_index in (0..player.worms.len()).rev() {
-                if player.worms[worm_index].health <= 0 {
-                    player.worms.remove(worm_index);
-                    if player.active_worm >= worm_index {
-                        if player.active_worm > 0 {
-                            player.active_worm -= 1;
-                        } else {
-                            player.active_worm = player.worms.len()-1;
-                        }
-                    }
-                }
-            }
+            player.clear_dead_worms();
             // Update the active worm
             if player.worms.len() > 0 {
                 player.active_worm = (player.active_worm + 1).checked_rem(player.worms.len()).unwrap_or(0);
@@ -224,21 +213,7 @@ impl GameBoard {
         }
 
         for player in &mut self.players {
-            // Remove dead worms
-            for worm_index in (0..player.worms.len()).rev() {
-                if player.worms[worm_index].health <= 0 {
-                    player.worms.remove(worm_index);
-                    if player.active_worm >= worm_index {
-                        player.active_worm = if player.active_worm > 0 {
-                            player.active_worm - 1
-                        } else if player.worms.len() > 0 {
-                             player.worms.len() - 1 
-                        } else {
-                            0
-                        };
-                    }
-                }
-            }
+            player.clear_dead_worms();
             // Update the active worm
             if player.worms.len() > 0 {
                 player.active_worm = (player.active_worm + 1).checked_rem(player.worms.len()).unwrap_or(0);
diff --git a/src/game/player.rs b/src/game/player.rs
index acfc494..3a9d36c 100644
--- a/src/game/player.rs
+++ b/src/game/player.rs
@@ -44,6 +44,161 @@ impl Player {
             .sum()
     }
 
+    pub fn clear_dead_worms(&mut self) {
+        for worm_index in (0..self.worms.len()).rev() {
+            if self.worms[worm_index].health <= 0 {
+                self.worms.remove(worm_index);
+                if self.active_worm >= worm_index {
+                    self.active_worm = if self.active_worm > 0 {
+                        self.active_worm - 1
+                    } else if self.worms.len() > 0 {
+                        self.worms.len() - 1 
+                    } else {
+                        0
+                    };
+                }
+            }
+        }
+    }
     // TODO: Cycle to next worm
 }
 
+#[cfg(test)]
+mod test {
+    use super::*;
+    
+    #[test]
+    fn clear_dead_worms_after_active_worm() {
+        let mut worms = ArrayVec::new();
+        worms.push(Worm {
+            id: 1,
+            health: 50,
+            position: Point2d::new(0, 0),
+            weapon_damage: 5,
+            weapon_range: 5
+        });
+        worms.push(Worm {
+            id: 2,
+            health: 10,
+            position: Point2d::new(0, 0),
+            weapon_damage: 5,
+            weapon_range: 5
+        });
+        worms.push(Worm {
+            id: 3,
+            health: -2,
+            position: Point2d::new(0, 0),
+            weapon_damage: 5,
+            weapon_range: 5
+        });
+        let mut player = Player {
+            active_worm: 1,
+            worms: worms
+        };
+
+        player.clear_dead_worms();
+
+        assert_eq!(2, player.worms.len());
+        assert_eq!(1, player.active_worm);
+
+        assert_eq!(1, player.worms[0].id);
+        assert_eq!(2, player.worms[1].id);
+    }
+
+    #[test]
+    fn clear_dead_worms_before_active_worm() {
+        let mut worms = ArrayVec::new();
+        worms.push(Worm {
+            id: 1,
+            health: 0,
+            position: Point2d::new(0, 0),
+            weapon_damage: 5,
+            weapon_range: 5
+        });
+        worms.push(Worm {
+            id: 2,
+            health: 10,
+            position: Point2d::new(0, 0),
+            weapon_damage: 5,
+            weapon_range: 5
+        });
+        worms.push(Worm {
+            id: 3,
+            health: 2,
+            position: Point2d::new(0, 0),
+            weapon_damage: 5,
+            weapon_range: 5
+        });
+        let mut player = Player {
+            active_worm: 1,
+            worms: worms
+        };
+
+        player.clear_dead_worms();
+
+        assert_eq!(2, player.worms.len());
+        assert_eq!(0, player.active_worm);
+
+        assert_eq!(2, player.worms[0].id);
+        assert_eq!(3, player.worms[1].id);
+    }
+
+    #[test]
+    fn clear_dead_worms_before_active_worm_wrapping() {
+        let mut worms = ArrayVec::new();
+        worms.push(Worm {
+            id: 1,
+            health: 0,
+            position: Point2d::new(0, 0),
+            weapon_damage: 5,
+            weapon_range: 5
+        });
+        worms.push(Worm {
+            id: 2,
+            health: 10,
+            position: Point2d::new(0, 0),
+            weapon_damage: 5,
+            weapon_range: 5
+        });
+        worms.push(Worm {
+            id: 3,
+            health: 2,
+            position: Point2d::new(0, 0),
+            weapon_damage: 5,
+            weapon_range: 5
+        });
+        let mut player = Player {
+            active_worm: 0,
+            worms: worms
+        };
+
+        player.clear_dead_worms();
+
+        assert_eq!(2, player.worms.len());
+        assert_eq!(1, player.active_worm);
+
+        assert_eq!(2, player.worms[0].id);
+        assert_eq!(3, player.worms[1].id);
+    }
+
+    #[test]
+    fn clear_last_dead_worm() {
+        let mut worms = ArrayVec::new();
+        worms.push(Worm {
+            id: 1,
+            health: -10,
+            position: Point2d::new(0, 0),
+            weapon_damage: 5,
+            weapon_range: 5
+        });
+        let mut player = Player {
+            active_worm: 0,
+            worms: worms
+        };
+
+        player.clear_dead_worms();
+
+        assert_eq!(0, player.worms.len());
+        // active worm is undefined in this case, but clearing the worms must not panic.
+    }
+}