src/main/java/Bäckahäst.java

@@ -1,2 +0,0 @@
-public class Bäckahäst extends Monster implements CanMove, CanAttack {
-}

src/main/java/Nixie.java

@@ -0,0 +1,6 @@
+public abstract class Nixie extends Monster implements CanMove, CanAttack {
+
+    public Nixie() {
+        super(0,0,Monster.DEFAULT_POSITION);
+    }
+}

src/main/java/Troll.java

@@ -1,2 +1,6 @@
-public class Troll extends Monster implements CanMove, CanAttack {
+public abstract class Troll extends Monster implements CanMove, CanAttack {
+
+    public Troll() {
+        super(0,0,Monster.DEFAULT_POSITION);
+    }
 }

src/test/java/MonsterTest.java

@@ -13,7 +13,7 @@ import java.util.*;
 import static org.hamcrest.MatcherAssert.*;
 import static org.hamcrest.Matchers.*;
 import static org.junit.jupiter.api.Assertions.*;
-import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.*;
 
 
 public class MonsterTest {
@@ -65,6 +65,13 @@ public class MonsterTest {
         assertThat(legalDestinations, hasItem(defaultShade.getPosition()));
     }
 
+    @Test
+    void shade_wont_move_to_same_position_as_player() {
+        Position destination = new Position(1, 1);
+        when(defaultPlayer.getPosition()).thenReturn(destination);
+        assertThat(defaultShade.moveTo(destination), equalTo(false));
+    }
+
     @Test
     void monster_cannot_do_anything_when_out_of_energy() {