String API - move multiple classes into a single class

core-java/src/main/java/com/baeldung/string/StringTest.java

@@ -0,0 +1,26 @@
+package com.baeldung.string;
+
+import static org.junit.Assert.assertArrayEquals;
+import static org.junit.Assert.assertEquals;
+
+import org.junit.Test;
+
+public class StringTest {
+
+    @Test
+    public void whenCallCodePointAt_thenDecimalUnicodeReturned() {
+        assertEquals(97, "abcd".codePointAt(0));
+    }
+
+    @Test
+    public void whenCallConcat_thenCorrect() {
+        assertEquals("elephant", "elep".concat("hant"));
+    }
+
+    @Test
+    public void whenGetBytes_thenCorrect() {
+        byte[] byteArray = "abcd".getBytes();
+        byte[] expected = new byte[] { 97, 98, 99, 100 };
+        assertArrayEquals(expected, byteArray);
+    }
+}