add case test method

Author: pwnipc

src/test/java/CaesarShiftTest.java

@@ -4,7 +4,12 @@
 
 class CaesarShiftTest {
     @Test
+    public void caesarShift_convertCase_String() {
+        CaesarShift testCase = new CaesarShift();
+        assertEquals("A", testCase.encrypt("a"));
+    }
 
+    @Test
     public void caesarShift_encryptChar_String(){
         CaesarShift testType = new CaesarShift();
         assertEquals("Y", testType.encrypt("Z"));