private static TextDocument createValidSimpleFixedFieldDocument() {
TextDocument doc = new TextDocument("Test");
Segment seg = new Segment("seg_1");
SimpleTextStructure struct = new SimpleTextStructure(doc.getName(), true);
Field field_1 = new Field(1, "A", FieldDataType.String.name(), "", "", 0, true);
field_1.setBeginPosition(0);
field_1.setLength(2);
seg.getFieldList().add(field_1);
Field field_2 = new Field(1, "B", FieldDataType.String.name(), "", "", 0, true);
field_2.setBeginPosition(2);
field_2.setLength(4);
seg.getFieldList().add(field_2);
struct.setSegment(seg);
doc.setStructure(struct);
doc.setDelimiter(FieldDelimiter.COMMA);
return doc;