Add test for Unicode form field names

DEVSIX-1357

Autoported commit.
Original commit hash: [30369f94e3]

Author: Benoit Lagae

itext.tests/itext.forms.tests/itext/forms/PdfFormFieldTest.cs

@@ -114,6 +114,19 @@ public virtual void FormFieldTest03() {
             }
         }
 
+        /// <exception cref="System.IO.IOException"/>
+        [NUnit.Framework.Test]
+        public virtual void UnicodeFormFieldTest() {
+            String filename = sourceFolder + "unicodeFormFieldFile.pdf";
+            PdfDocument pdfDoc = new PdfDocument(new PdfReader(filename));
+            PdfAcroForm form = PdfAcroForm.GetAcroForm(pdfDoc, true);
+            IDictionary<String, PdfFormField> formFields = form.GetFormFields();
+            byte[] result = new byte[] { (byte)0xFE, (byte)0xFF, (byte)0x5E, (byte)0x10, (byte)0x53, (byte)0xF7, (byte
+                )0x00, (byte)0x31 };
+            // 帐号1: account number 1
+            NUnit.Framework.Assert.AreEqual(formFields.Keys.ToArray(new String[1])[0].GetBytes(), result);
+        }
+
         /// <exception cref="System.IO.IOException"/>
         /// <exception cref="System.Exception"/>
         [NUnit.Framework.Test]

itext.tests/itext.forms.tests/resources/itext/forms/PdfFormFieldTest/unicodeFormFieldFile.pdf

@@ -1 +1 @@
-21a17e7e7b030b840aa32277d4657a66843ae25d
+30369f94e3e97d6837a55ab929a4c05c25a2515c