PDFBOX-6119: expand test coverage

git-svn-id: https://svn.apache.org/repos/asf/pdfbox/trunk@1930464 13f79535-47bb-0310-9956-ffa450edef68

Author: THausherr

xmpbox/src/test/java/org/apache/xmpbox/DateConverterTest.java

@@ -26,6 +26,7 @@
 import java.io.IOException;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNull;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 
 import java.text.SimpleDateFormat;
@@ -157,6 +158,9 @@ void testDateConversion() throws IOException
         assertEquals(DateConverter.toCalendar(testString1).toInstant(),
                 LocalDateTime.parse(testString1, ISO_LOCAL_DATE_TIME).atZone(ZoneId.of("UTC"))
                         .toInstant());
+
+        assertNull(DateConverter.toCalendar(null));
+        assertNull(DateConverter.toCalendar(""));
     }
 
     /**
@@ -176,6 +180,16 @@ void testDateFormatting() throws IOException
                     dateFormat.format(DateConverter.toCalendar(DateConverter.toISO8601(cal,true)).getTime())
                 );
 
+        cal = DateConverter.toCalendar("2015-02-02T16:37:19.192+09:09");
+        assertEquals(dateFormat.format(cal.getTime()), 
+                    dateFormat.format(DateConverter.toCalendar(DateConverter.toISO8601(cal,true)).getTime())
+                );
+
+        cal = DateConverter.toCalendar("2015-02-02T16:37:19.192+10:10");
+        assertEquals(dateFormat.format(cal.getTime()), 
+                    dateFormat.format(DateConverter.toCalendar(DateConverter.toISO8601(cal,true)).getTime())
+                );
+
         // PDFBOX-6107
         cal = DateConverter.toCalendar("0000-01-01");
         cal.setTimeZone(TimeZone.getTimeZone("UTC"));