diff --git a/src/test/java/edu/ntnu/idi/idatt2003/gruppe42/Model/Calculator/PurchaseCalculatorTest.java b/src/test/java/edu/ntnu/idi/idatt2003/gruppe42/Model/Calculator/PurchaseCalculatorTest.java
index 6870d4c..da36d61 100644
--- a/src/test/java/edu/ntnu/idi/idatt2003/gruppe42/Model/Calculator/PurchaseCalculatorTest.java
+++ b/src/test/java/edu/ntnu/idi/idatt2003/gruppe42/Model/Calculator/PurchaseCalculatorTest.java
@@ -30,22 +30,36 @@ void testCalculateGross() {
     BigDecimal expectedGross = new BigDecimal("1000");
     assertEquals(0, expectedGross.compareTo(calculator.calculateGross()));
     assertNotEquals(0, new BigDecimal("100").compareTo(calculator.calculateGross()));
+    assertNotEquals(0, new BigDecimal("-1000").compareTo(calculator.calculateGross()));
+    assertNotEquals(0, new BigDecimal("999.999").compareTo(calculator.calculateGross()));
+    assertNotEquals(0, new BigDecimal("1000.0001").compareTo(calculator.calculateGross()));
   }
 
   @Test
   void testCalculateCommission() {
     BigDecimal expectedCommission = new BigDecimal("10");
     assertEquals(0, expectedCommission.compareTo(calculator.calculateCommission()));
+    assertNotEquals(0, new BigDecimal("1").compareTo(calculator.calculateCommission()));
+    assertNotEquals(0, new BigDecimal("-10").compareTo(calculator.calculateCommission()));
+    assertNotEquals(0, new BigDecimal("9.9").compareTo(calculator.calculateCommission()));
+    assertNotEquals(0, new BigDecimal("10.01").compareTo(calculator.calculateCommission()));
   }
 
   @Test
   void testCalculateTax() {
     assertEquals(0, BigDecimal.ZERO.compareTo(calculator.calculateTax()));
+    assertNotEquals(0, new BigDecimal("1").compareTo(calculator.calculateTax()));
+    assertNotEquals(0, new BigDecimal("0.1").compareTo(calculator.calculateTax()));
+    assertNotEquals(0, new BigDecimal("-0.1").compareTo(calculator.calculateTax()));
   }
 
   @Test
   void testCalculateTotal() {
     BigDecimal expectedTotal = new BigDecimal("1010");
     assertEquals(0, expectedTotal.compareTo(calculator.calculateTotal()));
+    assertNotEquals(0, new BigDecimal("1000").compareTo(calculator.calculateTotal()));
+    assertNotEquals(0, new BigDecimal("-1010").compareTo(calculator.calculateTotal()));
+    assertNotEquals(0, new BigDecimal("1009.99").compareTo(calculator.calculateTotal()));
+    assertNotEquals(0, new BigDecimal("1010.001").compareTo(calculator.calculateTotal()));
   }
 }
diff --git a/src/test/java/edu/ntnu/idi/idatt2003/gruppe42/Model/Calculator/SaleCalculatorTest.java b/src/test/java/edu/ntnu/idi/idatt2003/gruppe42/Model/Calculator/SaleCalculatorTest.java
index 4519596..5cb3161 100644
--- a/src/test/java/edu/ntnu/idi/idatt2003/gruppe42/Model/Calculator/SaleCalculatorTest.java
+++ b/src/test/java/edu/ntnu/idi/idatt2003/gruppe42/Model/Calculator/SaleCalculatorTest.java
@@ -1,6 +1,7 @@
 package edu.ntnu.idi.idatt2003.gruppe42.Model.Calculator;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotEquals;
 
 import edu.ntnu.idi.idatt2003.gruppe42.Model.Share;
 import edu.ntnu.idi.idatt2003.gruppe42.Model.Stock;
@@ -16,6 +17,7 @@ public class SaleCalculatorTest {
 
   @BeforeEach
   void setUp() {
+    // Setup test data
     purchasePrice = new BigDecimal("100");
     salesPrice = new BigDecimal("150");
     quantity = new BigDecimal("10");
@@ -29,23 +31,40 @@ void setUp() {
   void testCalculateGross() {
     BigDecimal expectedGross = new BigDecimal("1500");
     assertEquals(0, expectedGross.compareTo(calculator.calculateGross()));
+    assertNotEquals(0, new BigDecimal("150").compareTo(calculator.calculateGross()));
+    assertNotEquals(0, new BigDecimal("-1500").compareTo(calculator.calculateGross()));
+    assertNotEquals(0, new BigDecimal("1499.99").compareTo(calculator.calculateGross()));
+    assertNotEquals(0, new BigDecimal("1500.01").compareTo(calculator.calculateGross()));
   }
 
   @Test
   void testCalculateCommission() {
     BigDecimal expectedCommission = new BigDecimal("15");
     assertEquals(0, expectedCommission.compareTo(calculator.calculateCommission()));
+    assertNotEquals(0, new BigDecimal("1.5").compareTo(calculator.calculateCommission()));
+    assertNotEquals(0, new BigDecimal("-15").compareTo(calculator.calculateCommission()));
+    assertNotEquals(0, new BigDecimal("14.99").compareTo(calculator.calculateCommission()));
+    assertNotEquals(0, new BigDecimal("15.01").compareTo(calculator.calculateCommission()));
+
   }
 
   @Test
   void testCalculateTax() {
     BigDecimal expectedTax = new BigDecimal("110");
     assertEquals(0, expectedTax.compareTo(calculator.calculateTax()));
+    assertNotEquals(0, new BigDecimal("100").compareTo(calculator.calculateTax()));
+    assertNotEquals(0, new BigDecimal("-110").compareTo(calculator.calculateTax()));
+    assertNotEquals(0, new BigDecimal("109.99").compareTo(calculator.calculateTax()));
+    assertNotEquals(0, new BigDecimal("110.01").compareTo(calculator.calculateTax()));
   }
 
   @Test
   void testCalculateTotal() {
     BigDecimal expectedTotal = new BigDecimal("1375");
     assertEquals(0, expectedTotal.compareTo(calculator.calculateTotal()));
+    assertNotEquals(0, new BigDecimal("1370").compareTo(calculator.calculateTotal()));
+    assertNotEquals(0, new BigDecimal("-1375").compareTo(calculator.calculateTotal()));
+    assertNotEquals(0, new BigDecimal("1375.01").compareTo(calculator.calculateTotal()));
+    assertNotEquals(0, new BigDecimal("1374.99").compareTo(calculator.calculateTotal()));
   }
 }
diff --git a/src/test/java/edu/ntnu/idi/idatt2003/gruppe42/Model/ExchangeTest.java b/src/test/java/edu/ntnu/idi/idatt2003/gruppe42/Model/ExchangeTest.java
index c8a9d4f..eb6bf72 100644
--- a/src/test/java/edu/ntnu/idi/idatt2003/gruppe42/Model/ExchangeTest.java
+++ b/src/test/java/edu/ntnu/idi/idatt2003/gruppe42/Model/ExchangeTest.java
@@ -2,6 +2,7 @@
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertNotEquals;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import java.math.BigDecimal;
@@ -30,7 +31,11 @@ void findStocksTest() {
     List<Stock> result = exchange.findStocks("Apple Inc.");
 
     assertEquals(1, result.size());
+    assertNotEquals(0, result.size());
     assertEquals("Apple Inc.", result.get(0).getCompany());
+    assertNotEquals("", result.get(0).getCompany());
+    assertNotEquals("AAPL", result.get(0).getCompany());
+    assertNotEquals("100", result.get(0).getCompany());
   }
 
   @Test
diff --git a/src/test/java/edu/ntnu/idi/idatt2003/gruppe42/Model/PlayerTest.java b/src/test/java/edu/ntnu/idi/idatt2003/gruppe42/Model/PlayerTest.java
index 3e2da0d..70aaf1a 100644
--- a/src/test/java/edu/ntnu/idi/idatt2003/gruppe42/Model/PlayerTest.java
+++ b/src/test/java/edu/ntnu/idi/idatt2003/gruppe42/Model/PlayerTest.java
@@ -1,6 +1,7 @@
 package edu.ntnu.idi.idatt2003.gruppe42.Model;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotEquals;
 import static org.junit.jupiter.api.Assertions.assertNotNull;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 
@@ -19,13 +20,23 @@ void setUp() {
 
   @Test
   void addMoneyTest() {
+    assertEquals(new BigDecimal("10000"), player.getMoney());
+    assertNotEquals(new BigDecimal("15000"), player.getMoney());
+
     player.addMoney(new BigDecimal("5000"));
+
+    assertNotEquals(new BigDecimal("10000"), player.getMoney());
     assertEquals(new BigDecimal("15000"), player.getMoney());
   }
 
   @Test
   void withdrawMoneyTest() {
+    assertEquals(new BigDecimal("10000"), player.getMoney());
+    assertNotEquals(new BigDecimal("5000"), player.getMoney());
+
     player.withdrawMoney(new BigDecimal("5000"));
+
+    assertNotEquals(new BigDecimal("10000"), player.getMoney());
     assertEquals(new BigDecimal("5000"), player.getMoney());
   }