Test: Test assert true for prime numbers

src/test/java/CalculationsTest.java

@@ -1,5 +1,7 @@
 import org.junit.Test;
+
 import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertTrue;
 
 public class CalculationsTest {
 
@@ -41,5 +43,12 @@ public class CalculationsTest {
         Calculations fact = new Calculations();
         fact.calculateFactorial(-5); // Should throw IllegalArgumentException
     }
+
+    @Test
+    public void testIsPrime() {
+        assertTrue(Calculations.isPrime(2)); // Prime number
+        assertTrue(Calculations.isPrime(3)); // Prime number
+        assertTrue(Calculations.isPrime(5)); // Prime number
+    }
 }