@Test
public void testFunctionInputInOutputMultipleTimes() {

	RichMapFunction<Float, ?> function = new FieldDuplicator<Float>();
	TypeInformation<?> ti = TypeExtractor.getMapReturnTypes(function, BasicTypeInfo.FLOAT_TYPE_INFO);
	Assert.assertTrue(ti.isTupleType());
	Assert.assertEquals(2, ti.getArity());
	TupleTypeInfo<?> tti = (TupleTypeInfo<?>) ti;
	Assert.assertEquals(BasicTypeInfo.FLOAT_TYPE_INFO, tti.getTypeAt(0));
	Assert.assertEquals(BasicTypeInfo.FLOAT_TYPE_INFO, tti.getTypeAt(1));
}