diff --git a/src/test/java/org/example/AdministrationTest.java b/src/test/java/org/example/AdministrationTest.java
index ef417e5..26b22f9 100644
--- a/src/test/java/org/example/AdministrationTest.java
+++ b/src/test/java/org/example/AdministrationTest.java
@@ -20,6 +20,46 @@ class AdministrationTest {
 
 
     }
+
+    @Test
+    void isNumber() {
+
+        Administration administration = new Administration();
+        String full01 = "S1002"; //Supposed student id
+        // String str1 = full01.substring(1); //String without the Letter
+        String full02 = "S100Z"; //Supposed student id
+        // String str2 = full02.substring(1); //String without the Letter
+        String full03 = "P1004"; //Supposed professor id
+        // String str3 = full03.substring(1); //String without the Letter
+
+        //checks if the substrings contain only digits
+        boolean test01 = administration.isNumber(full01);
+        boolean test02 = administration.isNumber(full02);
+        boolean test03 = administration.isNumber(full03);
+
+        assertEquals(true, test01); //only digits besides the first letter
+        assertEquals(false, test02); // false, because the Z at the end
+        assertEquals(true, test03); //only digits besides the first letter
+
+    }
+
+    @Test
+    void rightPrefix() {
+        Administration administration = new Administration();
+
+        String full01 = "S1002"; //Supposed Student id
+        String full02 = "s100Z"; //Supposed Student id
+        String full03 = "X1004"; // Supposed Professor id
+
+
+        boolean test01 = administration.rightPrefix(full01, 1); //checks if the id is correct,  "1" because we are expecting a student id
+        boolean test02 = administration.rightPrefix(full02, 1); //checks if the id is correct, "1" because we are expecting a student id
+        boolean test03 = administration.rightPrefix(full03, 3); //checks if the id is correct, "3" because we are expecting a professor id
+
+        assertEquals(true, test01);
+        assertEquals(false, test02);
+        assertEquals(false, test03);
+    }
 @org.junit.jupiter.api.Test
 
     void findStudentById(){