Test: Added testCalculateAverageGradeUsingTotalCredits()

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

@@ -123,4 +123,16 @@ class StudentTest {
 
     }
 
+    @Test
+    void testCalculateAverageGradeUsingTotalCredits() {
+        Student student = new Student("John Doe", "S1001", "Student");
+        Course math = new Course("Math", "M101", 5);
+        Course physics = new Course("Physics", "P101", 10);
+        student.getCourseGrades().put(math, "15");
+        student.getCourseGrades().put(physics, "12");
+
+        double expectedAverage = ((15.0 * 5) + (12.0 * 10)) / (5 + 10);
+        assertEquals(expectedAverage, student.calculateAverageGrade(), 0.01, "The calculated average grade is incorrect.");
+    }
+
 }