public function testGetSortFieldNameReturnsNull()
{
$mockedFieldNameResolver = $this->getMockedFieldNameResolver(array('getSearchableFieldMap', 'getIndexFieldName'));
$sortClauseMock = $this->getSortClauseMock();
$mockedFieldNameResolver->expects($this->once())->method('getSearchableFieldMap')->will($this->returnValue(array('content_type_identifier' => array('field_definition_identifier' => array('field_definition_id' => 'field_definition_id', 'field_type_identifier' => 'field_type_identifier')))));
$fieldName = $mockedFieldNameResolver->getSortFieldName($sortClauseMock, 'non_existent_content_type_identifier', 'non_existent_field_definition_identifier', 'field_name');
$this->assertNull($fieldName);
}