bit Flipper im the making 🐬

src/test/java/ch/fhnw/kry/SPNTest.java

@@ -33,4 +33,21 @@ class SPNTest {
 
         // System.out.print(Integer.toHexString(spn.substitution(x)));
     }
+
+    @Test
+    void swapBits() {
+        var spn = new SPN();
+
+        // given 
+        int x = 0xA;
+        int r = 0xC;
+
+        // when
+        int y = spn.swapBits(x, 1, 2);
+        int yy = spn.swapBits(x, 2, 1);
+
+        // then
+        assertEquals(r, y);
+        assertEquals(r, yy);
+    }
 }