def testFieldTooltip(self):
     f = QgsField('my_string', QVariant.String, 'string')
     self.assertEqual(QgsFieldModel.fieldToolTip(f), '<b>my_string</b><p>string</p>')
     f.setAlias('my alias')
     self.assertEqual(QgsFieldModel.fieldToolTip(f), '<b>my alias</b> (my_string)<p>string</p>')
     f.setLength(20)
     self.assertEqual(QgsFieldModel.fieldToolTip(f), '<b>my alias</b> (my_string)<p>string (20)</p>')
     f = QgsField('my_real', QVariant.Double, 'real', 8, 3)
     self.assertEqual(QgsFieldModel.fieldToolTip(f), '<b>my_real</b><p>real (8, 3)</p>')

    def testGettersSetters(self):
        """ test model getters/setters """
        l = create_layer()
        m = QgsFieldModel()

        self.assertFalse(m.layer())
        m.setLayer(l)
        self.assertEqual(m.layer(), l)

        m.setAllowExpression(True)
        self.assertTrue(m.allowExpression())
        m.setAllowExpression(False)
        self.assertFalse(m.allowExpression())

        m.setAllowEmptyFieldName(True)
        self.assertTrue(m.allowEmptyFieldName())
        m.setAllowEmptyFieldName(False)
        self.assertFalse(m.allowEmptyFieldName())

def create_model():
    l = create_layer()
    m = QgsFieldModel()
    m.setLayer(l)
    return l, m