diff --git a/src/main/java/it/polimi/ingsw/gc14/Model/Slot.java b/src/main/java/it/polimi/ingsw/gc14/Model/Slot.java
index 0db305b..3219bc1 100644
--- a/src/main/java/it/polimi/ingsw/gc14/Model/Slot.java
+++ b/src/main/java/it/polimi/ingsw/gc14/Model/Slot.java
@@ -169,8 +169,8 @@ public class Slot implements Serializable {
     public String toStringTUI()
     {
         StringBuilder  s = new StringBuilder(" ");
-        for(int i=0;i<this.getNUpper();i++) s.append("▲");
-        for(int i=0;i<this.getNLower();i++) s.append("▼");
+        s.repeat("▲", Math.max(0, this.getNUpper()));
+        s.repeat("▼", Math.max(0, this.getNLower()));
         if(getFood()!=0) s.append("+").append(getFood()).append(" \uD83C\uDF56");
         s.append(" ");
         return s.toString();
diff --git a/src/main/java/it/polimi/ingsw/gc14/View/TUI/AsciiTable.java b/src/main/java/it/polimi/ingsw/gc14/View/TUI/AsciiTable.java
index c642922..eb5fe21 100644
--- a/src/main/java/it/polimi/ingsw/gc14/View/TUI/AsciiTable.java
+++ b/src/main/java/it/polimi/ingsw/gc14/View/TUI/AsciiTable.java
@@ -108,7 +108,7 @@ public class AsciiTable {
     private String hline(String l, String m, String r, int maxWidth) {
         var sb = new StringBuilder(l);
         for (int i = 0; i < cols; i++) {
-            sb.append(s.h().repeat(maxWidth));
+            sb.repeat(Objects.requireNonNull(s.h()), maxWidth);
             if (i < cols - 1) sb.append(m);
         }
         return sb.append(r).toString();
diff --git a/src/test/java/it/polimi/ingsw/gc14/Model/PlayerTest.java b/src/test/java/it/polimi/ingsw/gc14/Model/PlayerTest.java
index ec2987a..b3e6025 100644
--- a/src/test/java/it/polimi/ingsw/gc14/Model/PlayerTest.java
+++ b/src/test/java/it/polimi/ingsw/gc14/Model/PlayerTest.java
@@ -19,7 +19,7 @@ class PlayerTest {
         Player p  = new Player(usr);
         assertEquals(usr, p.getUserName());
         assertTrue(p.getUserName().length() <= 32);
-        assertTrue(!p.getUserName().isEmpty());
+        assertFalse(p.getUserName().isEmpty());
     }
 
     @Test
@@ -174,7 +174,7 @@ class PlayerTest {
         assertTrue(p.getBuildingCards().isEmpty());
 
         assertTrue(p.getUserName().length() <= 32);
-        assertTrue(!p.getUserName().isEmpty());
+        assertFalse(p.getUserName().isEmpty());
     }
 
     @Test