CSV-264: Test to cover getAllowDuplicateHeaderNames.

Author: SethFalco

src/test/java/org/apache/commons/csv/CSVFormatTest.java

@@ -930,6 +930,15 @@ public void testWithEscape() {
         assertEquals(Character.valueOf('&'), formatWithEscape.getEscapeCharacter());
     }
 
+    @Test
+    public void testWithEmptyDuplicates() {
+        final CSVFormat formatWithEmptyDuplicates =
+            CSVFormat.DEFAULT.withDuplicateHeaderMode(DuplicateHeaderMode.ALLOW_EMPTY);
+
+        assertEquals(DuplicateHeaderMode.ALLOW_EMPTY, formatWithEmptyDuplicates.getDuplicateHeaderMode());
+        assertFalse(formatWithEmptyDuplicates.getAllowDuplicateHeaderNames());
+    }
+
     @Test
     public void testWithEscapeCRThrowsExceptions() {
         assertThrows(IllegalArgumentException.class, () -> CSVFormat.DEFAULT.withEscape(CR));