diff --git a/desktop/pom.xml b/desktop/pom.xml
index 9842bdfa..fe513dc6 100644
--- a/desktop/pom.xml
+++ b/desktop/pom.xml
@@ -76,6 +76,14 @@
                     <release>25</release>
                 </configuration>
             </plugin>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-surefire-plugin</artifactId>
+                <version>3.2.5</version>
+                <configuration>
+                    <argLine>--add-opens org.example.petshopdesktop/org.example.petshopdesktop=ALL-UNNAMED</argLine>
+                </configuration>
+            </plugin>
             <plugin>
                 <groupId>org.openjfx</groupId>
                 <artifactId>javafx-maven-plugin</artifactId>
diff --git a/desktop/src/main/java/org/example/petshopdesktop/Validator.java b/desktop/src/main/java/org/example/petshopdesktop/Validator.java
index 9c6f78a6..cf51eb1e 100644
--- a/desktop/src/main/java/org/example/petshopdesktop/Validator.java
+++ b/desktop/src/main/java/org/example/petshopdesktop/Validator.java
@@ -13,6 +13,7 @@ public class Validator {
         if (value == null || value.isBlank()){
             msg += name + " is required. \n";
         }
+
         return msg;
     }
 
@@ -24,8 +25,13 @@ public class Validator {
      */
     public static String isNonNegativeDouble(String value, String name){
         String msg ="";
+        if (value == null) {
+            msg += name + " must be a number.\n";
+
+            return msg;
+        }
         double result;
-        try{
+        try {
             result = Double.parseDouble(value);
             if (result < 0){
                 msg += name + " must be greater than or equal 0. \n";
@@ -34,6 +40,7 @@ public class Validator {
         catch (NumberFormatException e){
             msg += name + " must be a number.\n";
         }
+
         return msg;
     }
 
@@ -47,8 +54,13 @@ public class Validator {
      */
     public static String isDoubleInRange(String value, String name, double minValue, double maxValue){
         String msg ="";
+        if (value == null) {
+            msg += name + " must be a number.\n";
+
+            return msg;
+        }
         double result;
-        try{
+        try {
             result = Double.parseDouble(value);
             if (result < minValue || result > maxValue){
                 msg += name + " must be between " + minValue + " and " + maxValue + "\n";
@@ -57,6 +69,7 @@ public class Validator {
         catch (NumberFormatException e){
             msg += name + " must be a number.\n";
         }
+
         return msg;
     }
 
@@ -69,7 +82,7 @@ public class Validator {
     public static String isNonNegativeInteger(String value, String name){
         String msg ="";
         int result;
-        try{
+        try {
             result = Integer.parseInt(value);
             if (result < 0){
                 msg += name + " must be greater than or equal 0. \n";
@@ -78,6 +91,7 @@ public class Validator {
         catch (NumberFormatException e){
             msg += name + " must be a whole number.\n";
         }
+
         return msg;
     }
 
@@ -90,9 +104,10 @@ public class Validator {
      */
     public static String isLessThanVarChars(String value, String name, int length){
         String msg ="";
-        if (value.length() > length){
+        if (value == null || value.length() > length){
             msg += name + " must be less than " + length + " characters. \n";
         }
+
         return msg;
     }
 
@@ -104,11 +119,17 @@ public class Validator {
      */
     public static String isValidEmail(String value, String name){
         String msg = "";
+        if (value == null) {
+            msg += name + " is not in a valid format. \n";
+
+            return msg;
+        }
         String regex = "^[A-Za-z0-9+_.-]+@[A-Za-z0-9.-]+\\.[A-Za-z]{2,}$";
 
         if (!value.matches(regex)){
             msg += name + " is not in a valid format. \n";
         }
+
         return msg;
     }
 
@@ -120,11 +141,17 @@ public class Validator {
      */
     public static String isValidPhoneNumber(String value, String name){
         String msg = "";
+        if (value == null) {
+            msg += name + " must be in format XXX-XXX-XXXX. \n";
+
+            return msg;
+        }
         String regex = "^\\d{3}-\\d{3}-\\d{4}$";
 
         if (!value.matches(regex)){
             msg += name + " must be in format XXX-XXX-XXXX. \n";
         }
+
         return msg;
     }
-}
+}
\ No newline at end of file
diff --git a/desktop/src/test/java/org/example/petshopdesktop/ValidatorTest.java b/desktop/src/test/java/org/example/petshopdesktop/ValidatorTest.java
new file mode 100644
index 00000000..61a8e0c8
--- /dev/null
+++ b/desktop/src/test/java/org/example/petshopdesktop/ValidatorTest.java
@@ -0,0 +1,213 @@
+//Validator JUnits tests
+
+package org.example.petshopdesktop;
+
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+class ValidatorTest {
+
+    //isPresent
+    @Test
+    void isPresent_nullValue_returnsError() {
+        String result = Validator.isPresent(null, "Name");
+        assertFalse(result.isEmpty(), "null value should produce an error message");
+    }
+
+    @Test
+    void isPresent_blankValue_returnsError() {
+        assertFalse(Validator.isPresent("   ", "Name").isEmpty());
+    }
+
+    @Test
+    void isPresent_emptyString_returnsError() {
+        assertFalse(Validator.isPresent("", "Name").isEmpty());
+    }
+
+    @Test
+    void isPresent_validValue_returnsEmpty() {
+        assertTrue(Validator.isPresent("Leon", "Name").isEmpty());
+    }
+
+    //isNonNegativeDouble
+    @Test
+    void isNonNegativeDouble_positiveValue_returnsEmpty() {
+        assertTrue(Validator.isNonNegativeDouble("5.5", "Price").isEmpty());
+    }
+
+    @Test
+    void isNonNegativeDouble_zero_returnsEmpty() {
+        assertTrue(Validator.isNonNegativeDouble("0", "Price").isEmpty());
+    }
+
+    @Test
+    void isNonNegativeDouble_negativeValue_returnsError() {
+        assertFalse(Validator.isNonNegativeDouble("-1.0", "Price").isEmpty());
+    }
+
+    @Test
+    void isNonNegativeDouble_nonNumeric_returnsError() {
+        assertFalse(Validator.isNonNegativeDouble("abc", "Price").isEmpty());
+    }
+
+    @Test
+    void isNonNegativeDouble_nullInput_returnsError() {
+        assertFalse(Validator.isNonNegativeDouble(null, "Price").isEmpty());
+    }
+
+    //isDoubleInRange
+    @Test
+    void isDoubleInRange_withinRange_returnsEmpty() {
+        assertTrue(Validator.isDoubleInRange("5.0", "Discount", 0.0, 10.0).isEmpty());
+    }
+
+    @Test
+    void isDoubleInRange_atMinBoundary_returnsEmpty() {
+        assertTrue(Validator.isDoubleInRange("0.0", "Discount", 0.0, 10.0).isEmpty());
+    }
+
+    @Test
+    void isDoubleInRange_atMaxBoundary_returnsEmpty() {
+        assertTrue(Validator.isDoubleInRange("10.0", "Discount", 0.0, 10.0).isEmpty());
+    }
+
+    @Test
+    void isDoubleInRange_belowMin_returnsError() {
+        assertFalse(Validator.isDoubleInRange("-1.0", "Discount", 0.0, 10.0).isEmpty());
+    }
+
+    @Test
+    void isDoubleInRange_aboveMax_returnsError() {
+        assertFalse(Validator.isDoubleInRange("11.0", "Discount", 0.0, 10.0).isEmpty());
+    }
+
+    @Test
+    void isDoubleInRange_nonNumeric_returnsError() {
+        assertFalse(Validator.isDoubleInRange("abc", "Discount", 0.0, 10.0).isEmpty());
+    }
+
+    @Test
+    void isDoubleInRange_nullInput_returnsError() {
+        assertFalse(Validator.isDoubleInRange(null, "Discount", 0.0, 10.0).isEmpty());
+    }
+
+    //isNonNegativeInteger
+    @Test
+    void isNonNegativeInteger_positiveValue_returnsEmpty() {
+        assertTrue(Validator.isNonNegativeInteger("10", "Quantity").isEmpty());
+    }
+
+    @Test
+    void isNonNegativeInteger_zero_returnsEmpty() {
+        assertTrue(Validator.isNonNegativeInteger("0", "Quantity").isEmpty());
+    }
+
+    @Test
+    void isNonNegativeInteger_negativeValue_returnsError() {
+        assertFalse(Validator.isNonNegativeInteger("-1", "Quantity").isEmpty());
+    }
+
+    @Test
+    void isNonNegativeInteger_decimal_returnsError() {
+        assertFalse(Validator.isNonNegativeInteger("1.5", "Quantity").isEmpty());
+    }
+
+    @Test
+    void isNonNegativeInteger_nonNumeric_returnsError() {
+        assertFalse(Validator.isNonNegativeInteger("abc", "Quantity").isEmpty());
+    }
+
+    @Test
+    void isNonNegativeInteger_nullInput_returnsError() {
+        assertFalse(Validator.isNonNegativeInteger(null, "Quantity").isEmpty());
+    }
+
+    //isLessThanVarChars
+    @Test
+    void isLessThanVarChars_withinLimit_returnsEmpty() {
+        assertTrue(Validator.isLessThanVarChars("Hello", "Name", 10).isEmpty());
+    }
+
+    @Test
+    void isLessThanVarChars_exactlyAtLimit_returnsEmpty() {
+        assertTrue(Validator.isLessThanVarChars("Hello", "Name", 5).isEmpty());
+    }
+
+    @Test
+    void isLessThanVarChars_exceedsLimit_returnsError() {
+        assertFalse(Validator.isLessThanVarChars("Hello World", "Name", 5).isEmpty());
+    }
+
+    @Test
+    void isLessThanVarChars_nullInput_returnsError() {
+        assertFalse(Validator.isLessThanVarChars(null, "Name", 10).isEmpty());
+    }
+
+    @Test
+    void isLessThanVarChars_emptyString_returnsEmpty() {
+        assertTrue(Validator.isLessThanVarChars("", "Name", 5).isEmpty());
+    }
+
+    //isValidEmail
+    @Test
+    void isValidEmail_validEmail_returnsEmpty() {
+        assertTrue(Validator.isValidEmail("user@example.com", "Email").isEmpty());
+    }
+
+    @Test
+    void isValidEmail_missingAtSign_returnsError() {
+        assertFalse(Validator.isValidEmail("userexample.com", "Email").isEmpty());
+    }
+
+    @Test
+    void isValidEmail_missingDomain_returnsError() {
+        assertFalse(Validator.isValidEmail("user@", "Email").isEmpty());
+    }
+
+    @Test
+    void isValidEmail_shortTld_returnsError() {
+        assertFalse(Validator.isValidEmail("user@example.c", "Email").isEmpty());
+    }
+
+    @Test
+    void isValidEmail_nullInput_returnsError() {
+        assertFalse(Validator.isValidEmail(null, "Email").isEmpty());
+    }
+
+    @Test
+    void isValidEmail_emptyString_returnsError() {
+        assertFalse(Validator.isValidEmail("", "Email").isEmpty());
+    }
+
+    //isValidPhoneNumber
+    @Test
+    void isValidPhoneNumber_validFormat_returnsEmpty() {
+        assertTrue(Validator.isValidPhoneNumber("403-555-1234", "Phone").isEmpty());
+    }
+
+    @Test
+    void isValidPhoneNumber_missingDashes_returnsError() {
+        assertFalse(Validator.isValidPhoneNumber("4035551234", "Phone").isEmpty());
+    }
+
+    @Test
+    void isValidPhoneNumber_lettersPresent_returnsError() {
+        assertFalse(Validator.isValidPhoneNumber("abc-def-ghij", "Phone").isEmpty());
+    }
+
+    @Test
+    void isValidPhoneNumber_wrongSegmentLength_returnsError() {
+        assertFalse(Validator.isValidPhoneNumber("40-5551-234", "Phone").isEmpty());
+    }
+
+    @Test
+    void isValidPhoneNumber_nullInput_returnsError() {
+        assertFalse(Validator.isValidPhoneNumber(null, "Phone").isEmpty());
+    }
+
+    @Test
+    void isValidPhoneNumber_emptyString_returnsError() {
+        assertFalse(Validator.isValidPhoneNumber("", "Phone").isEmpty());
+    }
+}