diff --git a/core-java/src/main/java/com/baeldung/string/CodePointAtTest.java b/core-java/src/main/java/com/baeldung/string/CodePointAtTest.java
new file mode 100644
index 0000000000..bce0e1af18
--- /dev/null
+++ b/core-java/src/main/java/com/baeldung/string/CodePointAtTest.java
@@ -0,0 +1,12 @@
+package com.baeldung.string;
+
+import static org.junit.Assert.assertEquals;
+import org.junit.Test;
+
+public class CodePointAtTest {
+
+    @Test
+    public void whenCallCodePointAt_thenDecimalUnicodeReturned() {
+        assertEquals(97, "abcd".codePointAt(0));
+    }
+}
diff --git a/core-java/src/main/java/com/baeldung/string/ConcatTest.java b/core-java/src/main/java/com/baeldung/string/ConcatTest.java
new file mode 100644
index 0000000000..4a7362b513
--- /dev/null
+++ b/core-java/src/main/java/com/baeldung/string/ConcatTest.java
@@ -0,0 +1,12 @@
+package com.baeldung.string;
+
+import static org.junit.Assert.assertEquals;
+import org.junit.Test;
+
+public class ConcatTest {
+    
+    @Test
+    public void whenCallConcat_thenCorrect() {
+        assertEquals("elephant", "elep".concat("hant"));
+    }
+}
diff --git a/core-java/src/main/java/com/baeldung/string/GetBytesTest.java b/core-java/src/main/java/com/baeldung/string/GetBytesTest.java
new file mode 100644
index 0000000000..22011678f0
--- /dev/null
+++ b/core-java/src/main/java/com/baeldung/string/GetBytesTest.java
@@ -0,0 +1,14 @@
+package com.baeldung.string;
+
+import static org.junit.Assert.assertArrayEquals;
+import org.junit.Test;
+
+public class GetBytesTest {
+
+    @Test
+    public void whenGetBytes_thenCorrect() {
+        byte[] byteArray = "abcd".getBytes();
+        byte[] expected = new byte[] { 97, 98, 99, 100 };
+        assertArrayEquals(expected, byteArray);
+    }
+}