Caesar crypt done

Crypto/src/main/java/Caesar.java

@@ -0,0 +1,19 @@
+public class Caesar extends ROT13 {
+
+
+    public Caesar() {
+
+    }
+
+    public Caesar(int shift) {
+        this.shift = shift;
+        this.shifted = rotateByNumber(alpha, shift);
+
+    }
+
+    public static String rotateByNumber (String input, int number) {
+
+        return input.substring(number) + input.substring(0, number);
+    }
+
+}

Crypto/src/test/java/CaesarTest.java

@@ -0,0 +1,102 @@
+import org.junit.Assert;
+import org.junit.Test;
+
+import static org.junit.Assert.*;
+
+public class CaesarTest {
+
+    @Test
+    public void rotateStringTest0() {
+        // Given
+        String s1 = "ABCDEF";
+        String s2 = "ABCDEF";
+
+        // When
+        Caesar cipher = new Caesar();
+        String actual = cipher.rotateByNumber(s1, 0);
+
+        // Then
+        assertTrue(actual.equals(s2));
+    }
+
+    @Test
+    public void rotateStringTest1() {
+        // Given
+        String s1 = "ABCDEF";
+        String s2 = "DEFABC";
+
+        // When
+        Caesar cipher = new Caesar();
+        String actual = cipher.rotateByNumber(s1, 3);
+
+        // Then
+        assertTrue(actual.equals(s2));
+    }
+
+    @Test
+    public void rotateStringTest2() {
+        // Given
+        String s1 = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
+        String s2 = "NOPQRSTUVWXYZABCDEFGHIJKLM";
+
+        // When
+        Caesar cipher = new Caesar();
+        String actual = cipher.rotateByNumber(s1, 13);
+        System.out.println(s1);
+        System.out.println(actual);
+        // Then
+        assertTrue(actual.equals(s2));
+    }
+
+    @Test
+    public void cryptTest1() {
+        // Given
+        Caesar cipher = new Caesar(13);
+
+        String Q1 = "Why did the chicken cross the road?";
+        String A1 = "Jul qvq gur puvpxra pebff gur ebnq?";
+
+        String Q2 = "Gb trg gb gur bgure fvqr!";
+        String A2 = "To get to the other side!";
+
+        // When
+        String actual = cipher.encrypt(Q1);
+        System.out.println(Q1);
+        System.out.println(A1);
+        // Then
+        Assert.assertEquals(A1, actual);
+
+        // When
+        String actual2 = cipher.decrypt(Q2);
+        System.out.println(Q2);
+        System.out.println(A2);
+        // Then
+        Assert.assertEquals(A2, actual2);
+    }
+
+    @Test
+    public void cryptTest2() {
+        // Given
+        Caesar cipher = new Caesar(4);
+
+        String Q1 = "This is a test of Caesar.";
+        String A1 = "Xlmw mw e xiwx sj geiwev.";
+
+        String Q2 = "Ynulpo wna bqj!";
+        String A2 = "Crypts are fun!";
+
+        // When
+        String actual = cipher.encrypt(Q1);
+        System.out.println(Q1);
+        System.out.println(A1);
+        // Then
+        Assert.assertEquals(A1, actual);
+
+        // When
+        String actual2 = cipher.decrypt(Q2);
+        System.out.println(Q2);
+        System.out.println(A2);
+        // Then
+        Assert.assertEquals(A2, actual2);
+    }
+}