Exemple #1
0
    def testCreateFeature(self):
        """ test creating a feature respecting defaults and constraints """
        layer = QgsVectorLayer("Point?field=fldtxt:string&field=fldint:integer&field=flddbl:double",
                               "addfeat", "memory")
        # add a bunch of features
        f = QgsFeature()
        f.setAttributes(["test", 123, 1.0])
        f1 = QgsFeature(2)
        f1.setAttributes(["test_1", 124, 1.1])
        f2 = QgsFeature(3)
        f2.setAttributes(["test_2", 125, 2.4])
        f3 = QgsFeature(4)
        f3.setAttributes(["test_3", 126, 1.7])
        f4 = QgsFeature(5)
        f4.setAttributes(["superpig", 127, 0.8])
        self.assertTrue(layer.dataProvider().addFeatures([f, f1, f2, f3, f4]))

        # no layer
        self.assertFalse(QgsVectorLayerUtils.createFeature(None).isValid())

        # basic tests
        f = QgsVectorLayerUtils.createFeature(layer)
        self.assertTrue(f.isValid())
        self.assertEqual(f.fields(), layer.fields())
        self.assertFalse(f.hasGeometry())
        self.assertEqual(f.attributes(), [NULL, NULL, NULL])

        # set geometry
        g = QgsGeometry.fromPointXY(QgsPointXY(100, 200))
        f = QgsVectorLayerUtils.createFeature(layer, g)
        self.assertTrue(f.hasGeometry())
        self.assertEqual(f.geometry().asWkt(), g.asWkt())

        # using attribute map
        f = QgsVectorLayerUtils.createFeature(layer, attributes={0: 'a', 2: 6.0})
        self.assertEqual(f.attributes(), ['a', NULL, 6.0])

        # layer with default value expression
        layer.setDefaultValueDefinition(2, QgsDefaultValue('3*4'))
        f = QgsVectorLayerUtils.createFeature(layer)
        self.assertEqual(f.attributes(), [NULL, NULL, 12])
        # we do not expect the default value expression to take precedence over the attribute map
        f = QgsVectorLayerUtils.createFeature(layer, attributes={0: 'a', 2: 6.0})
        self.assertEqual(f.attributes(), ['a', NULL, 6.0])
        # layer with default value expression based on geometry
        layer.setDefaultValueDefinition(2, QgsDefaultValue('3*$x'))
        f = QgsVectorLayerUtils.createFeature(layer, g)
        #adjusted so that input value and output feature are the same
        self.assertEqual(f.attributes(), [NULL, NULL, 300.0])
        layer.setDefaultValueDefinition(2, QgsDefaultValue(None))

        # test with violated unique constraints
        layer.setFieldConstraint(1, QgsFieldConstraints.ConstraintUnique)
        f = QgsVectorLayerUtils.createFeature(layer, attributes={0: 'test_1', 1: 123})
        # since field 1 has Unique Constraint, it ignores value 123 that already has been set and sets to 128
        self.assertEqual(f.attributes(), ['test_1', 128, NULL])
        layer.setFieldConstraint(0, QgsFieldConstraints.ConstraintUnique)
        # since field 0 and 1 already have values test_1 and 123, the output must be a new unique value
        f = QgsVectorLayerUtils.createFeature(layer, attributes={0: 'test_1', 1: 123})
        self.assertEqual(f.attributes(), ['test_4', 128, NULL])
Exemple #2
0
    def testConstraintOverwrite(self):
        """ test that Postgres provider constraints can't be overwritten by vector layer method """
        vl = QgsVectorLayer(
            '%s table="qgis_test"."constraints" sql=' % (self.dbconn),
            "constraints", "postgres")
        self.assertTrue(vl.isValid())

        self.assertTrue(vl.dataProvider().fieldConstraints(0)
                        & QgsFieldConstraints.ConstraintNotNull)
        self.assertTrue(vl.fields().at(0).constraints().constraints()
                        & QgsFieldConstraints.ConstraintNotNull)

        # add a constraint at the layer level
        vl.setFieldConstraint(0, QgsFieldConstraints.ConstraintUnique)

        # should be no change at provider level
        self.assertTrue(vl.dataProvider().fieldConstraints(0)
                        & QgsFieldConstraints.ConstraintNotNull)

        # but layer should still keep provider constraints...
        self.assertTrue(vl.fields().at(0).constraints().constraints()
                        & QgsFieldConstraints.ConstraintNotNull)
        self.assertTrue(
            vl.fieldConstraints(0) & QgsFieldConstraints.ConstraintNotNull)
        # ...in addition to layer level constraint
        self.assertTrue(vl.fields().at(0).constraints().constraints()
                        & QgsFieldConstraints.ConstraintUnique)
        self.assertTrue(
            vl.fieldConstraints(0) & QgsFieldConstraints.ConstraintUnique)
Exemple #3
0
    def testCreateFeature(self):
        """ test creating a feature respecting defaults and constraints """
        layer = QgsVectorLayer("Point?field=fldtxt:string&field=fldint:integer&field=flddbl:double",
                               "addfeat", "memory")
        # add a bunch of features
        f = QgsFeature()
        f.setAttributes(["test", 123, 1.0])
        f1 = QgsFeature(2)
        f1.setAttributes(["test_1", 124, 1.1])
        f2 = QgsFeature(3)
        f2.setAttributes(["test_2", 125, 2.4])
        f3 = QgsFeature(4)
        f3.setAttributes(["test_3", 126, 1.7])
        f4 = QgsFeature(5)
        f4.setAttributes(["superpig", 127, 0.8])
        self.assertTrue(layer.dataProvider().addFeatures([f, f1, f2, f3, f4]))

        # no layer
        self.assertFalse(QgsVectorLayerUtils.createFeature(None).isValid())

        # basic tests
        f = QgsVectorLayerUtils.createFeature(layer)
        self.assertTrue(f.isValid())
        self.assertEqual(f.fields(), layer.fields())
        self.assertFalse(f.hasGeometry())
        self.assertEqual(f.attributes(), [NULL, NULL, NULL])

        # set geometry
        g = QgsGeometry.fromPoint(QgsPoint(100, 200))
        f = QgsVectorLayerUtils.createFeature(layer, g)
        self.assertTrue(f.hasGeometry())
        self.assertEqual(f.geometry().exportToWkt(), g.exportToWkt())

        # using attribute map
        f = QgsVectorLayerUtils.createFeature(layer, attributes={0: 'a', 2: 6.0})
        self.assertEqual(f.attributes(), ['a', NULL, 6.0])

        # layer with default value expression
        layer.setDefaultValueExpression(2, '3*4')
        f = QgsVectorLayerUtils.createFeature(layer)
        self.assertEqual(f.attributes(), [NULL, NULL, 12.0])
        # we expect the default value expression to take precedence over the attribute map
        f = QgsVectorLayerUtils.createFeature(layer, attributes={0: 'a', 2: 6.0})
        self.assertEqual(f.attributes(), ['a', NULL, 12.0])
        # layer with default value expression based on geometry
        layer.setDefaultValueExpression(2, '3*$x')
        f = QgsVectorLayerUtils.createFeature(layer, g)
        self.assertEqual(f.attributes(), [NULL, NULL, 300.0])
        layer.setDefaultValueExpression(2, None)

        # test with violated unique constraints
        layer.setFieldConstraint(1, QgsFieldConstraints.ConstraintUnique)
        f = QgsVectorLayerUtils.createFeature(layer, attributes={0: 'test_1', 1: 123})
        self.assertEqual(f.attributes(), ['test_1', 128, NULL])
        layer.setFieldConstraint(0, QgsFieldConstraints.ConstraintUnique)
        f = QgsVectorLayerUtils.createFeature(layer, attributes={0: 'test_1', 1: 123})
        self.assertEqual(f.attributes(), ['test_4', 128, NULL])
Exemple #4
0
    def testCreateFeature(self):
        """ test creating a feature respecting defaults and constraints """
        layer = QgsVectorLayer("Point?field=fldtxt:string&field=fldint:integer&field=flddbl:double",
                               "addfeat", "memory")
        # add a bunch of features
        f = QgsFeature()
        f.setAttributes(["test", 123, 1.0])
        f1 = QgsFeature(2)
        f1.setAttributes(["test_1", 124, 1.1])
        f2 = QgsFeature(3)
        f2.setAttributes(["test_2", 125, 2.4])
        f3 = QgsFeature(4)
        f3.setAttributes(["test_3", 126, 1.7])
        f4 = QgsFeature(5)
        f4.setAttributes(["superpig", 127, 0.8])
        self.assertTrue(layer.dataProvider().addFeatures([f, f1, f2, f3, f4]))

        # no layer
        self.assertFalse(QgsVectorLayerUtils.createFeature(None).isValid())

        # basic tests
        f = QgsVectorLayerUtils.createFeature(layer)
        self.assertTrue(f.isValid())
        self.assertEqual(f.fields(), layer.fields())
        self.assertFalse(f.hasGeometry())
        self.assertEqual(f.attributes(), [NULL, NULL, NULL])

        # set geometry
        g = QgsGeometry.fromPoint(QgsPoint(100, 200))
        f = QgsVectorLayerUtils.createFeature(layer, g)
        self.assertTrue(f.hasGeometry())
        self.assertEqual(f.geometry().exportToWkt(), g.exportToWkt())

        # using attribute map
        f = QgsVectorLayerUtils.createFeature(layer, attributes={0: 'a', 2: 6.0})
        self.assertEqual(f.attributes(), ['a', NULL, 6.0])

        # layer with default value expression
        layer.setDefaultValueExpression(2, '3*4')
        f = QgsVectorLayerUtils.createFeature(layer)
        self.assertEqual(f.attributes(), [NULL, NULL, 12.0])
        # we expect the default value expression to take precedence over the attribute map
        f = QgsVectorLayerUtils.createFeature(layer, attributes={0: 'a', 2: 6.0})
        self.assertEqual(f.attributes(), ['a', NULL, 12.0])
        # layer with default value expression based on geometry
        layer.setDefaultValueExpression(2, '3*$x')
        f = QgsVectorLayerUtils.createFeature(layer, g)
        self.assertEqual(f.attributes(), [NULL, NULL, 300.0])
        layer.setDefaultValueExpression(2, None)

        # test with violated unique constraints
        layer.setFieldConstraint(1, QgsFieldConstraints.ConstraintUnique)
        f = QgsVectorLayerUtils.createFeature(layer, attributes={0: 'test_1', 1: 123})
        self.assertEqual(f.attributes(), ['test_1', 128, NULL])
        layer.setFieldConstraint(0, QgsFieldConstraints.ConstraintUnique)
        f = QgsVectorLayerUtils.createFeature(layer, attributes={0: 'test_1', 1: 123})
        self.assertEqual(f.attributes(), ['test_4', 128, NULL])
    def testConstraintOverwrite(self):
        """ test that Postgres provider constraints can't be overwritten by vector layer method """
        vl = QgsVectorLayer('%s table="qgis_test"."constraints" sql=' % (self.dbconn), "constraints", "postgres")
        self.assertTrue(vl.isValid())

        self.assertTrue(vl.dataProvider().fieldConstraints(0) & QgsFieldConstraints.ConstraintNotNull)
        self.assertTrue(vl.fields().at(0).constraints().constraints() & QgsFieldConstraints.ConstraintNotNull)

        # add a constraint at the layer level
        vl.setFieldConstraint(0, QgsFieldConstraints.ConstraintUnique)

        # should be no change at provider level
        self.assertTrue(vl.dataProvider().fieldConstraints(0) & QgsFieldConstraints.ConstraintNotNull)

        # but layer should still keep provider constraints...
        self.assertTrue(vl.fields().at(0).constraints().constraints() & QgsFieldConstraints.ConstraintNotNull)
        self.assertTrue(vl.fieldConstraints(0) & QgsFieldConstraints.ConstraintNotNull)
        # ...in addition to layer level constraint
        self.assertTrue(vl.fields().at(0).constraints().constraints() & QgsFieldConstraints.ConstraintUnique)
        self.assertTrue(vl.fieldConstraints(0) & QgsFieldConstraints.ConstraintUnique)
Exemple #6
0
    def testCreateFeature(self):
        """ test creating a feature respecting defaults and constraints """
        layer = QgsVectorLayer(
            "Point?field=fldtxt:string&field=fldint:integer&field=flddbl:double",
            "addfeat", "memory")
        # add a bunch of features
        f = QgsFeature()
        f.setAttributes(["test", 123, 1.0])
        f1 = QgsFeature(2)
        f1.setAttributes(["test_1", 124, 1.1])
        f2 = QgsFeature(3)
        f2.setAttributes(["test_2", 125, 2.4])
        f3 = QgsFeature(4)
        f3.setAttributes(["test_3", 126, 1.7])
        f4 = QgsFeature(5)
        f4.setAttributes(["superpig", 127, 0.8])
        self.assertTrue(layer.dataProvider().addFeatures([f, f1, f2, f3, f4]))

        # no layer
        self.assertFalse(QgsVectorLayerUtils.createFeature(None).isValid())

        # basic tests
        f = QgsVectorLayerUtils.createFeature(layer)
        self.assertTrue(f.isValid())
        self.assertEqual(f.fields(), layer.fields())
        self.assertFalse(f.hasGeometry())
        self.assertEqual(f.attributes(), [NULL, NULL, NULL])

        # set geometry
        g = QgsGeometry.fromPointXY(QgsPointXY(100, 200))
        f = QgsVectorLayerUtils.createFeature(layer, g)
        self.assertTrue(f.hasGeometry())
        self.assertEqual(f.geometry().asWkt(), g.asWkt())

        # using attribute map
        f = QgsVectorLayerUtils.createFeature(layer,
                                              attributes={
                                                  0: 'a',
                                                  2: 6.0
                                              })
        self.assertEqual(f.attributes(), ['a', NULL, 6.0])

        # layer with default value expression
        layer.setDefaultValueDefinition(2, QgsDefaultValue('3*4'))
        f = QgsVectorLayerUtils.createFeature(layer)
        self.assertEqual(f.attributes(), [NULL, NULL, 12])
        # we do not expect the default value expression to take precedence over the attribute map
        f = QgsVectorLayerUtils.createFeature(layer,
                                              attributes={
                                                  0: 'a',
                                                  2: 6.0
                                              })
        self.assertEqual(f.attributes(), ['a', NULL, 6.0])
        # layer with default value expression based on geometry
        layer.setDefaultValueDefinition(2, QgsDefaultValue('3*$x'))
        f = QgsVectorLayerUtils.createFeature(layer, g)
        #adjusted so that input value and output feature are the same
        self.assertEqual(f.attributes(), [NULL, NULL, 300.0])
        layer.setDefaultValueDefinition(2, QgsDefaultValue(None))

        # test with violated unique constraints
        layer.setFieldConstraint(1, QgsFieldConstraints.ConstraintUnique)
        f = QgsVectorLayerUtils.createFeature(layer,
                                              attributes={
                                                  0: 'test_1',
                                                  1: 123
                                              })
        # since field 1 has Unique Constraint, it ignores value 123 that already has been set and sets to 128
        self.assertEqual(f.attributes(), ['test_1', 128, NULL])
        layer.setFieldConstraint(0, QgsFieldConstraints.ConstraintUnique)
        # since field 0 and 1 already have values test_1 and 123, the output must be a new unique value
        f = QgsVectorLayerUtils.createFeature(layer,
                                              attributes={
                                                  0: 'test_1',
                                                  1: 123
                                              })
        self.assertEqual(f.attributes(), ['test_4', 128, NULL])

        # test with violated unique constraints and default value expression providing unique value
        layer.setDefaultValueDefinition(1, QgsDefaultValue('130'))
        f = QgsVectorLayerUtils.createFeature(layer,
                                              attributes={
                                                  0: 'test_1',
                                                  1: 123
                                              })
        # since field 1 has Unique Constraint, it ignores value 123 that already has been set and adds the default value
        self.assertEqual(f.attributes(), ['test_4', 130, NULL])
        # fallback: test with violated unique constraints and default value expression providing already existing value
        # add the feature with the default value:
        self.assertTrue(layer.dataProvider().addFeatures([f]))
        f = QgsVectorLayerUtils.createFeature(layer,
                                              attributes={
                                                  0: 'test_1',
                                                  1: 123
                                              })
        # since field 1 has Unique Constraint, it ignores value 123 that already has been set and adds the default value
        # and since the default value providing an already existing value (130) it generates a unique value (next int: 131)
        self.assertEqual(f.attributes(), ['test_5', 131, NULL])
        layer.setDefaultValueDefinition(1, QgsDefaultValue(None))

        # test with manually correct unique constraint
        f = QgsVectorLayerUtils.createFeature(layer,
                                              attributes={
                                                  0: 'test_1',
                                                  1: 132
                                              })
        self.assertEqual(f.attributes(), ['test_5', 132, NULL])
        """ test creating a feature respecting unique values of postgres provider """
        layer = QgsVectorLayer(
            "Point?field=fldtxt:string&field=fldint:integer&field=flddbl:double",
            "addfeat", "memory")

        # init connection string
        dbconn = 'dbname=\'qgis_test\''
        if 'QGIS_PGTEST_DB' in os.environ:
            dbconn = os.environ['QGIS_PGTEST_DB']

        # create a vector layer
        pg_layer = QgsVectorLayer(
            '{} table="qgis_test"."authors" sql='.format(dbconn), "authors",
            "postgres")
        self.assertTrue(pg_layer.isValid())
        # check the default clause
        default_clause = 'nextval(\'qgis_test.authors_pk_seq\'::regclass)'
        self.assertEqual(pg_layer.dataProvider().defaultValueClause(0),
                         default_clause)

        # though default_clause is after the first create not unique (until save), it should fill up all the features with it
        pg_layer.startEditing()
        f = QgsVectorLayerUtils.createFeature(pg_layer)
        self.assertEqual(f.attributes(), [default_clause, NULL])
        self.assertTrue(pg_layer.addFeatures([f]))
        self.assertTrue(
            QgsVectorLayerUtils.valueExists(pg_layer, 0, default_clause))
        f = QgsVectorLayerUtils.createFeature(pg_layer)
        self.assertEqual(f.attributes(), [default_clause, NULL])
        self.assertTrue(pg_layer.addFeatures([f]))
        f = QgsVectorLayerUtils.createFeature(pg_layer)
        self.assertEqual(f.attributes(), [default_clause, NULL])
        self.assertTrue(pg_layer.addFeatures([f]))
        # if a unique value is passed, use it
        f = QgsVectorLayerUtils.createFeature(pg_layer,
                                              attributes={
                                                  0: 40,
                                                  1: NULL
                                              })
        self.assertEqual(f.attributes(), [40, NULL])
        # and if a default value is configured use it as well
        pg_layer.setDefaultValueDefinition(0, QgsDefaultValue('11*4'))
        f = QgsVectorLayerUtils.createFeature(pg_layer)
        self.assertEqual(f.attributes(), [44, NULL])
        pg_layer.rollBack()
    def testCreateFeature(self):
        """ test creating a feature respecting defaults and constraints """
        layer = QgsVectorLayer("Point?field=fldtxt:string&field=fldint:integer&field=flddbl:double",
                               "addfeat", "memory")
        # add a bunch of features
        f = QgsFeature()
        f.setAttributes(["test", 123, 1.0])
        f1 = QgsFeature(2)
        f1.setAttributes(["test_1", 124, 1.1])
        f2 = QgsFeature(3)
        f2.setAttributes(["test_2", 125, 2.4])
        f3 = QgsFeature(4)
        f3.setAttributes(["test_3", 126, 1.7])
        f4 = QgsFeature(5)
        f4.setAttributes(["superpig", 127, 0.8])
        self.assertTrue(layer.dataProvider().addFeatures([f, f1, f2, f3, f4]))

        # no layer
        self.assertFalse(QgsVectorLayerUtils.createFeature(None).isValid())

        # basic tests
        f = QgsVectorLayerUtils.createFeature(layer)
        self.assertTrue(f.isValid())
        self.assertEqual(f.fields(), layer.fields())
        self.assertFalse(f.hasGeometry())
        self.assertEqual(f.attributes(), [NULL, NULL, NULL])

        # set geometry
        g = QgsGeometry.fromPointXY(QgsPointXY(100, 200))
        f = QgsVectorLayerUtils.createFeature(layer, g)
        self.assertTrue(f.hasGeometry())
        self.assertEqual(f.geometry().asWkt(), g.asWkt())

        # using attribute map
        f = QgsVectorLayerUtils.createFeature(layer, attributes={0: 'a', 2: 6.0})
        self.assertEqual(f.attributes(), ['a', NULL, 6.0])

        # layer with default value expression
        layer.setDefaultValueDefinition(2, QgsDefaultValue('3*4'))
        f = QgsVectorLayerUtils.createFeature(layer)
        self.assertEqual(f.attributes(), [NULL, NULL, 12])
        # we do not expect the default value expression to take precedence over the attribute map
        f = QgsVectorLayerUtils.createFeature(layer, attributes={0: 'a', 2: 6.0})
        self.assertEqual(f.attributes(), ['a', NULL, 6.0])
        # layer with default value expression based on geometry
        layer.setDefaultValueDefinition(2, QgsDefaultValue('3*$x'))
        f = QgsVectorLayerUtils.createFeature(layer, g)
        #adjusted so that input value and output feature are the same
        self.assertEqual(f.attributes(), [NULL, NULL, 300.0])
        layer.setDefaultValueDefinition(2, QgsDefaultValue(None))

        # test with violated unique constraints
        layer.setFieldConstraint(1, QgsFieldConstraints.ConstraintUnique)
        f = QgsVectorLayerUtils.createFeature(layer, attributes={0: 'test_1', 1: 123})
        # since field 1 has Unique Constraint, it ignores value 123 that already has been set and sets to 128
        self.assertEqual(f.attributes(), ['test_1', 128, NULL])
        layer.setFieldConstraint(0, QgsFieldConstraints.ConstraintUnique)
        # since field 0 and 1 already have values test_1 and 123, the output must be a new unique value
        f = QgsVectorLayerUtils.createFeature(layer, attributes={0: 'test_1', 1: 123})
        self.assertEqual(f.attributes(), ['test_4', 128, NULL])

        # test with violated unique constraints and default value expression providing unique value
        layer.setDefaultValueDefinition(1, QgsDefaultValue('130'))
        f = QgsVectorLayerUtils.createFeature(layer, attributes={0: 'test_1', 1: 123})
        # since field 1 has Unique Constraint, it ignores value 123 that already has been set and adds the default value
        self.assertEqual(f.attributes(), ['test_4', 130, NULL])
        # fallback: test with violated unique constraints and default value expression providing already existing value
        # add the feature with the default value:
        self.assertTrue(layer.dataProvider().addFeatures([f]))
        f = QgsVectorLayerUtils.createFeature(layer, attributes={0: 'test_1', 1: 123})
        # since field 1 has Unique Constraint, it ignores value 123 that already has been set and adds the default value
        # and since the default value providing an already existing value (130) it generates a unique value (next int: 131)
        self.assertEqual(f.attributes(), ['test_5', 131, NULL])
        layer.setDefaultValueDefinition(1, QgsDefaultValue(None))

        # test with manually correct unique constraint
        f = QgsVectorLayerUtils.createFeature(layer, attributes={0: 'test_1', 1: 132})
        self.assertEqual(f.attributes(), ['test_5', 132, NULL])

        """ test creating a feature respecting unique values of postgres provider """
        layer = QgsVectorLayer("Point?field=fldtxt:string&field=fldint:integer&field=flddbl:double",
                               "addfeat", "memory")

        # init connection string
        dbconn = 'dbname=\'qgis_test\''
        if 'QGIS_PGTEST_DB' in os.environ:
            dbconn = os.environ['QGIS_PGTEST_DB']

        # create a vector layer
        pg_layer = QgsVectorLayer('{} table="qgis_test"."authors" sql='.format(dbconn), "authors", "postgres")
        self.assertTrue(pg_layer.isValid())
        # check the default clause
        default_clause = 'nextval(\'qgis_test.authors_pk_seq\'::regclass)'
        self.assertEqual(pg_layer.dataProvider().defaultValueClause(0), default_clause)

        # though default_clause is after the first create not unique (until save), it should fill up all the features with it
        pg_layer.startEditing()
        f = QgsVectorLayerUtils.createFeature(pg_layer)
        self.assertEqual(f.attributes(), [default_clause, NULL])
        self.assertTrue(pg_layer.addFeatures([f]))
        self.assertTrue(QgsVectorLayerUtils.valueExists(pg_layer, 0, default_clause))
        f = QgsVectorLayerUtils.createFeature(pg_layer)
        self.assertEqual(f.attributes(), [default_clause, NULL])
        self.assertTrue(pg_layer.addFeatures([f]))
        f = QgsVectorLayerUtils.createFeature(pg_layer)
        self.assertEqual(f.attributes(), [default_clause, NULL])
        self.assertTrue(pg_layer.addFeatures([f]))
        # if a unique value is passed, use it
        f = QgsVectorLayerUtils.createFeature(pg_layer, attributes={0: 40, 1: NULL})
        self.assertEqual(f.attributes(), [40, NULL])
        # and if a default value is configured use it as well
        pg_layer.setDefaultValueDefinition(0, QgsDefaultValue('11*4'))
        f = QgsVectorLayerUtils.createFeature(pg_layer)
        self.assertEqual(f.attributes(), [44, NULL])
        pg_layer.rollBack()
    def testCreateFeature(self):
        """ test creating a feature respecting defaults and constraints """
        layer = QgsVectorLayer("Point?field=fldtxt:string&field=fldint:integer&field=flddbl:double",
                               "addfeat", "memory")
        # add a bunch of features
        f = QgsFeature()
        f.setAttributes(["test", 123, 1.0])
        f1 = QgsFeature(2)
        f1.setAttributes(["test_1", 124, 1.1])
        f2 = QgsFeature(3)
        f2.setAttributes(["test_2", 125, 2.4])
        f3 = QgsFeature(4)
        f3.setAttributes(["test_3", 126, 1.7])
        f4 = QgsFeature(5)
        f4.setAttributes(["superpig", 127, 0.8])
        self.assertTrue(layer.dataProvider().addFeatures([f, f1, f2, f3, f4]))

        # no layer
        self.assertFalse(QgsVectorLayerUtils.createFeature(None).isValid())

        # basic tests
        f = QgsVectorLayerUtils.createFeature(layer)
        self.assertTrue(f.isValid())
        self.assertEqual(f.fields(), layer.fields())
        self.assertFalse(f.hasGeometry())
        self.assertEqual(f.attributes(), [NULL, NULL, NULL])

        # set geometry
        g = QgsGeometry.fromPointXY(QgsPointXY(100, 200))
        f = QgsVectorLayerUtils.createFeature(layer, g)
        self.assertTrue(f.hasGeometry())
        self.assertEqual(f.geometry().asWkt(), g.asWkt())

        # using attribute map
        f = QgsVectorLayerUtils.createFeature(layer, attributes={0: 'a', 2: 6.0})
        self.assertEqual(f.attributes(), ['a', NULL, 6.0])

        # layer with default value expression
        layer.setDefaultValueDefinition(2, QgsDefaultValue('3*4'))
        f = QgsVectorLayerUtils.createFeature(layer)
        self.assertEqual(f.attributes(), [NULL, NULL, 12])
        # we do not expect the default value expression to take precedence over the attribute map
        f = QgsVectorLayerUtils.createFeature(layer, attributes={0: 'a', 2: 6.0})
        self.assertEqual(f.attributes(), ['a', NULL, 6.0])
        # layer with default value expression based on geometry
        layer.setDefaultValueDefinition(2, QgsDefaultValue('3*$x'))
        f = QgsVectorLayerUtils.createFeature(layer, g)
        #adjusted so that input value and output feature are the same
        self.assertEqual(f.attributes(), [NULL, NULL, 300.0])
        layer.setDefaultValueDefinition(2, QgsDefaultValue(None))

        # test with violated unique constraints
        layer.setFieldConstraint(1, QgsFieldConstraints.ConstraintUnique)
        f = QgsVectorLayerUtils.createFeature(layer, attributes={0: 'test_1', 1: 123})
        # since field 1 has Unique Constraint, it ignores value 123 that already has been set and sets to 128
        self.assertEqual(f.attributes(), ['test_1', 128, NULL])
        layer.setFieldConstraint(0, QgsFieldConstraints.ConstraintUnique)
        # since field 0 and 1 already have values test_1 and 123, the output must be a new unique value
        f = QgsVectorLayerUtils.createFeature(layer, attributes={0: 'test_1', 1: 123})
        self.assertEqual(f.attributes(), ['test_4', 128, NULL])

        # test with violated unique constraints and default value expression providing unique value
        layer.setDefaultValueDefinition(1, QgsDefaultValue('130'))
        f = QgsVectorLayerUtils.createFeature(layer, attributes={0: 'test_1', 1: 123})
        # since field 1 has Unique Constraint, it ignores value 123 that already has been set and adds the default value
        self.assertEqual(f.attributes(), ['test_4', 130, NULL])
        # fallback: test with violated unique constraints and default value expression providing already existing value
        # add the feature with the default value:
        self.assertTrue(layer.dataProvider().addFeatures([f]))
        f = QgsVectorLayerUtils.createFeature(layer, attributes={0: 'test_1', 1: 123})
        # since field 1 has Unique Constraint, it ignores value 123 that already has been set and adds the default value
        # and since the default value providing an already existing value (130) it generates a unique value (next int: 131)
        self.assertEqual(f.attributes(), ['test_5', 131, NULL])
        layer.setDefaultValueDefinition(1, QgsDefaultValue(None))

        # test with manually correct unique constraint
        f = QgsVectorLayerUtils.createFeature(layer, attributes={0: 'test_1', 1: 132})
        self.assertEqual(f.attributes(), ['test_5', 132, NULL])