BAEL-3097 init for mapstruct custom mapping method

mapstruct/src/test/java/com/baeldung/mapper/UrlMapperTest.java

@@ -0,0 +1,22 @@
+package com.baeldung.mapper;
+
+import com.baeldung.dto.UrlDTO;
+import com.baeldung.entity.UrlObject;
+import org.junit.Test;
+
+import static org.junit.Assert.assertEquals;
+
+public class UrlMapperTest {
+
+    @Test
+    public void givenDomains_whenCallDomainMapper_thenReturnDomainsWithoutProtocols() {
+        UrlDTO dto = new UrlDTO();
+        dto.setUrl("http://www.baeldung.com");
+        dto.setSubUrl("https://www.baeldung.com");
+
+        UrlObject urlObject = UrlMapper.INSTANCE.urlObjectDomainMapper(dto);
+
+        assertEquals(urlObject.getUrl(), "www.baeldung.com");
+        assertEquals(urlObject.getSubUrl(), "www.baeldung.com");
+    }
+}