diff --git a/src/test/java/com/lgtoledo/CodeGeneratorTest.java b/src/test/java/com/lgtoledo/CodeGeneratorTest.java
new file mode 100644
index 0000000..e371a34
--- /dev/null
+++ b/src/test/java/com/lgtoledo/CodeGeneratorTest.java
@@ -0,0 +1,25 @@
+package com.lgtoledo;
+
+import org.junit.jupiter.api.Test;
+
+import com.lgtoledo.utils.CodeGenerator;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+public class CodeGeneratorTest {
+    
+    @Test
+    public void testGenerateCode() {
+        String code = CodeGenerator.generateCode(6);
+        assertNotNull(code);
+        assertEquals(6, code.length());
+    }
+
+    @Test
+    public void testGenerateCodeWithZeroLength() {
+        String code = CodeGenerator.generateCode(0);
+        assertNotNull(code);
+        assertEquals("", code);
+    }
+
+}
\ No newline at end of file
diff --git a/src/test/java/com/lgtoledo/UtilsTest.java b/src/test/java/com/lgtoledo/UtilsTest.java
new file mode 100644
index 0000000..5a30c38
--- /dev/null
+++ b/src/test/java/com/lgtoledo/UtilsTest.java
@@ -0,0 +1,77 @@
+package com.lgtoledo;
+
+import org.junit.jupiter.api.Test;
+
+import com.lgtoledo.utils.Utils;
+
+import java.time.LocalDateTime;
+import java.util.Optional;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+public class UtilsTest {
+
+    @Test
+    public void testIsValidUrl() {
+        String longUrlRegex = "^https://.*$";
+        assertFalse(Utils.isValidUrl(Optional.of("http://www.mercadolibre.com"), longUrlRegex));
+        assertTrue(Utils.isValidUrl(Optional.of("https://www.mercadolibre.com"), longUrlRegex));
+        assertFalse(Utils.isValidUrl(Optional.of("www.mercadolibre.com"), longUrlRegex));
+        assertFalse(Utils.isValidUrl(Optional.of("http://www.mercadolibre"), longUrlRegex));
+        assertFalse(Utils.isValidUrl(Optional.of("http://www.mercadolibre."), longUrlRegex));
+        assertFalse(Utils.isValidUrl(Optional.of("http://www.mercadolibre.com/"), longUrlRegex));
+        assertFalse(Utils.isValidUrl(Optional.empty(), longUrlRegex));
+    }
+
+    @Test
+    public void testExtractLastPart() {
+        String shortUrl = "http://localhost:8080/abc123";
+        String lastPart = Utils.extractLastPart(shortUrl);
+        assertEquals("abc123", lastPart);
+    }
+
+    @Test
+    public void testGetCurrentUtcDateTime() {
+        LocalDateTime dateTime = Utils.getCurrentUtcDateTime();
+        assertNotNull(dateTime);
+    }
+
+    @Test
+    public void testValidShortLink() {
+        String baseUrl = "https://short.link";
+        assertTrue(Utils.isShortLinkValid(baseUrl, "https://short.link/l/abc123"));
+    }
+
+    @Test
+    public void testInvalidShortLinkWrongLength() {
+        String baseUrl = "https://short.link";
+        assertFalse(Utils.isShortLinkValid(baseUrl, "https://short.link/l/abc12345"));
+    }
+
+    @Test
+    public void testInvalidShortLinkWrongChars() {
+        String baseUrl = "https://short.link";
+        assertFalse(Utils.isShortLinkValid(baseUrl, "https://short.link/l/abc_!@"));
+    }
+
+    @Test
+    public void testInvalidShortLinkWithoutL() {
+        String baseUrl = "https://short.link";
+        assertFalse(Utils.isShortLinkValid(baseUrl, "https://short.link/abc123"));
+    }
+
+    // test if short link is null
+    @Test
+    public void testInvalidShortLinkNull() {
+        String baseUrl = "https://short.link";
+        assertFalse(Utils.isShortLinkValid(baseUrl, null));
+    }
+
+    // test if short link is empty
+    @Test
+    public void testInvalidShortLinkEmpty() {
+        String baseUrl = "https://short.link";
+        assertFalse(Utils.isShortLinkValid(baseUrl, ""));
+    }
+
+}
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