item.id = "aaa";
item.categories = new String[] { "aaa", "bbb", "ccc" };
SolrInputDocument out = binder.toSolrInputDocument( item );
Assert.assertEquals( item.id, out.getFieldValue( "id" ) );
SolrInputField catfield = out.getField( "cat" );
Assert.assertEquals( 3, catfield.getValueCount() );
Assert.assertEquals( "[aaa, bbb, ccc]", catfield.getValue().toString() );
// Test the error on not settable stuff...
NotGettableItem ng = new NotGettableItem();
ng.setInStock( false );
try {