Added test for calculateTotalCredits Method in StudentTest class

src/test/java/org/example/StudentTest.java

@@ -108,4 +108,19 @@ class StudentTest {
         assertEquals(newGrade, student.getCourseGrades().get(course), "Grade update for course does not match expected new grade.");
     }
 
+    @Test
+    void calculateTotalCredits(){
+        Administration admin = new Administration();
+        Student student = new Student("John Doe", "S1001", "Student");
+        Course course = new Course("Introduction to Java", "C101", 3);
+        admin.addStudents(student);
+        admin.addCourse(course);
+        admin.enrollStudentInCourse("S1001", "C101");
+
+        int credits = student.calculateTotalCredits();
+
+        assertEquals(3,credits);
+
+    }
+
 }