feat: update unit test scenarios

Author: ricardogarfe

src/test/java/com/geekshubs/calculator/CalculatorTest.java

@@ -14,17 +14,17 @@ public void testSum() {
     }
 
     @Test
-    public void testSub() {
-        assertEquals(4, new Calculator(12, 8, 12 - 8).getResult());
+    public void testRest() {
+        assertEquals(2, new Calculator(4,2, 4-2).getResult());
     }
 
     @Test
-    public void testMul() {
-        assertEquals(88, new Calculator(11, 8, 11 * 8).getResult());
+    public void testMult() {
+        assertEquals(8, new Calculator(4,2, 4*2).getResult());
     }
 
     @Test
     public void testDiv() {
-        assertEquals(1, new Calculator(12, 12, 12 / 12).getResult());
+        assertEquals(6, new Calculator(36,6, 36/6).getResult());
     }
 }