Add testRfc4180QuoteSingleChar().

Author: garydgregory

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

@@ -53,6 +53,7 @@
  */
 public class CSVPrinterTest {
 
+    private static final char EURO_CH = '\u20AC';
     private static final char DQUOTE_CHAR = '"';
     private static final char BACKSLASH_CH = '\\';
     private static final char QUOTE_CH = '\'';
@@ -806,6 +807,15 @@ public void testPrinter1() throws IOException {
         }
     }
 
+    @Test
+    public void testRfc4180QuoteSingleChar() throws IOException {
+        final StringWriter sw = new StringWriter();
+        try (final CSVPrinter printer = new CSVPrinter(sw, CSVFormat.RFC4180)) {
+            printer.printRecord(EURO_CH, "Deux");
+            assertEquals("\"" + EURO_CH + "\",Deux" + recordSeparator, sw.toString());
+        }
+    }
+
     @Test
     public void testPrinter2() throws IOException {
         final StringWriter sw = new StringWriter();