OZG-5010,OZG-5397 trim empty strings to null

bescheid-manager/src/main/java/de/ozgcloud/bescheid/attacheditem/BescheidItemMapper.java

@@ -86,8 +86,14 @@ public class BescheidItemMapper {
 		if (attachmentsObject instanceof Collection<?> attachments) {
 			return (Collection<String>) attachments;
 		}
-		return nonNull(attachmentsObject)
-				? List.of(String.valueOf(attachmentsObject))
-				: null;
+		if (attachmentsObject instanceof String attachment) {
+			attachment = StringUtils.trimToNull(attachment);
+			if (nonNull(attachment)) {
+				return List.of(attachment);
+			}
+		} else if (nonNull(attachmentsObject)) {
+			return List.of(String.valueOf(attachmentsObject));
+		}
+		return null; //NOSONAR
 	}
 }

bescheid-manager/src/test/java/de/ozgcloud/bescheid/attacheditem/BescheidItemMapperTest.java

@@ -29,8 +29,11 @@ import static org.mockito.Mockito.*;
 import java.util.List;
 import java.util.Map;
 
+import org.junit.jupiter.api.DisplayName;
 import org.junit.jupiter.api.Nested;
 import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.NullAndEmptySource;
 import org.mockito.InjectMocks;
 import org.mockito.Mock;
 import org.mockito.Spy;
@@ -242,9 +245,11 @@ class BescheidItemMapperTest {
 			assertThat(result).containsExactly(BescheidItemTestFactory.ATTACHMENT);
 		}
 
-		@Test
-		void shouldReturnNull() {
-			var result = mapper.toAttachments(null);
+		@DisplayName("should return null")
+		@ParameterizedTest(name = "when attachmentsObject is \"{0}\"")
+		@NullAndEmptySource
+		void shouldReturnNull(String attachmentsObject) {
+			var result = mapper.toAttachments(attachmentsObject);
 
 			assertThat(result).isNull();
 		}