pom.xml

@@ -13,6 +13,7 @@
         <maven.compiler.target>23</maven.compiler.target>
         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
     </properties>
+
     <dependencies>
         <dependency>
             <groupId>org.junit.jupiter</groupId>
@@ -33,5 +34,5 @@
             <scope>test</scope>
         </dependency>
     </dependencies>
+</project>
 
-</project>

src/main/java/Action.java

@@ -0,0 +1,11 @@
+public abstract class Action {
+    private int cost;
+
+    public Action(int cost) {
+
+    }
+
+    public int getCost() {
+        return cost;
+    }
+}

src/main/java/Actions.java

@@ -0,0 +1,9 @@
+public enum Actions {
+    HEAL(2);
+
+    private final int cost;
+
+    Actions(int cost) {
+        this.cost = cost;
+    }
+}

src/main/java/Healing.java

@@ -0,0 +1,8 @@
+public class Healing extends Action {
+    private int healthRegenerated;
+
+    public Healing() {
+        super(2);
+
+    }
+}

src/main/java/Monster.java

@@ -19,6 +19,7 @@ public abstract class Monster {
 
     public void kill() {
         health = 0;
+        energy = 0;
         isAlive = false;
     }
 
@@ -40,7 +41,7 @@ public abstract class Monster {
 
     abstract void heal();
 
-    abstract void takeDamage();
+    abstract void takeDamage(int amount);
 
     abstract void recharge();
 

src/main/java/Shade.java

@@ -3,24 +3,38 @@ import java.util.*;
 
 public class Shade extends Monster {
     public static final List<Biomes> habitat = Collections.unmodifiableList(Arrays.asList(Biomes.COAST, Biomes.FOREST, Biomes.GRASSLAND, Biomes.MOUNTAIN));
+    public static final int MAX_HEALTH = 20;
+    public static final int MAX_ENERGY = 14;
 
-    private static final int MAX_HEALTH = 20;
-    private static final int MAX_ENERGY = 14;
-
-
+    private static final int HEALTH_PER_HEAL = 2;
+    private static final int ENERGY_COST_PER_HEAL = 1;
 
     public Shade() {
         super(MAX_HEALTH, MAX_ENERGY, Monster.DEFAULT_POSITION);
     }
 
     public void heal() {
-        if (isAlive()) {
-            health += 2;
+        if (!isAlive) {
+            throw new IllegalStateException("This shade is dead");
+        }
+        if (health < MAX_HEALTH) {
+            health += HEALTH_PER_HEAL;
+            energy -= ENERGY_COST_PER_HEAL;
+            enforceHealthMaximum();
         }
     }
 
-    public void takeDamage() {
+    public void takeDamage(int amount) {
+        if (amount < 0) {
+            throw new IllegalArgumentException("'amount' must be a positive integer");
+        }
 
+        if (health - amount <= 0) {
+            kill();
+        }
+        else {
+            health =- amount;
+        }
     }
 
     public void recharge() {
@@ -34,4 +48,10 @@ public class Shade extends Monster {
     public void moveTo(Position position) {
 
     }
+
+    private void enforceHealthMaximum() {
+        if (health > MAX_HEALTH) {
+            health = MAX_HEALTH;
+        }
+    }
 }

src/test/java/MonsterTest.java

@@ -9,6 +9,7 @@ import Shared.*;
 import org.junit.jupiter.api.*;
 import static org.hamcrest.MatcherAssert.*;
 import static org.hamcrest.Matchers.*;
+import static org.junit.jupiter.api.Assertions.*;
 import static org.mockito.Mockito.mock;
 
 
@@ -30,14 +31,13 @@ public class MonsterTest {
 
     @Test
     void reaching_zero_health_triggers_death() {
-        defaultShade.kill();
+        defaultShade.takeDamage(Shade.MAX_HEALTH);
         assertThat(false, equalTo(defaultShade.isAlive()));
     }
 
     @Test
     void monster_cannot_regain_health_after_death() {
         defaultShade.kill();
-        defaultShade.heal();
-        assertThat(defaultShade.getHealth(), equalTo(0));
+        assertThrows(IllegalStateException.class, () -> defaultShade.heal());
     }
 }