def testPartNum(self):
        # test geometry_part_num variable
        s = QgsLineSymbol()
        s.deleteSymbolLayer(0)

        sym_layer = QgsGeometryGeneratorSymbolLayer.create({'geometryModifier': 'segments_to_lines($geometry)'})
        sym_layer.setSymbolType(QgsSymbol.Line)
        s.appendSymbolLayer(sym_layer)

        marker_line = QgsMarkerLineSymbolLayer(False)
        marker_line.setPlacement(QgsMarkerLineSymbolLayer.FirstVertex)
        f = QgsFontUtils.getStandardTestFont('Bold', 24)
        marker = QgsFontMarkerSymbolLayer(f.family(), 'x', 24, QColor(255, 255, 0))
        marker.setDataDefinedProperty(QgsSymbolLayer.PropertyCharacter, QgsProperty.fromExpression('@geometry_part_num'))
        marker_symbol = QgsMarkerSymbol()
        marker_symbol.changeSymbolLayer(0, marker)
        marker_line.setSubSymbol(marker_symbol)
        marker_line.setAverageAngleLength(0)
        line_symbol = QgsLineSymbol()
        line_symbol.changeSymbolLayer(0, marker_line)
        sym_layer.setSubSymbol(line_symbol)

        # rendering test
        g = QgsGeometry.fromWkt('LineString(0 0, 10 0, 10 10, 0 10)')
        rendered_image = self.renderGeometry(s, g, buffer=4)
        assert self.imageCheck('part_num_variable', 'part_num_variable', rendered_image)

        marker.setDataDefinedProperty(QgsSymbolLayer.PropertyCharacter,
                                      QgsProperty.fromExpression('@geometry_part_count'))

        # rendering test
        g = QgsGeometry.fromWkt('LineString(0 0, 10 0, 10 10, 0 10)')
        rendered_image = self.renderGeometry(s, g, buffer=4)
        assert self.imageCheck('part_count_variable', 'part_count_variable', rendered_image)

    def testFontMarkerUnitDefault(self):
        symbol = QgsFontMarkerSymbolLayer('sans', ',', 10, QColor('black'), 45)
        symbol.setOffset(QPointF(5, 10))
        dom, root = self.symbolToSld(symbol)
        # print("Font marker unit mm: " + dom.toString())

        # Check the size has been rescaled
        self.assertStaticSize(root, '36')
        self.assertStaticRotation(root, '45')
        self.assertStaticDisplacement(root, 18, 36)

    def testFontMarkerUnitPixel(self):
        symbol = QgsFontMarkerSymbolLayer('sans', ',', 10, QColor('black'), 45)
        symbol.setOffset(QPointF(5, 10))
        symbol.setOutputUnit(QgsUnitTypes.RenderPixels)
        dom, root = self.symbolToSld(symbol)
        # print ("Font marker unit mm: " + dom.toString())

        # Check the size has been rescaled
        self.assertStaticSize(root, '10')
        self.assertStaticRotation(root, '45')
        self.assertStaticDisplacement(root, 5, 10)

    def testQgsFontMarkerSymbolLayer(self):
        """
        Create a new style from a .sld file and match test
        """
        mTestName = "QgsFontMarkerSymbolLayer"
        mFilePath = QDir.toNativeSeparators("%s/symbol_layer/%s.sld" % (unitTestDataPath(), mTestName))

        mDoc = QDomDocument(mTestName)
        mFile = QFile(mFilePath)
        mFile.open(QIODevice.ReadOnly)
        mDoc.setContent(mFile, True)
        mFile.close()
        mSymbolLayer = QgsFontMarkerSymbolLayer.createFromSld(
            mDoc.elementsByTagName("PointSymbolizer").item(0).toElement()
        )

        mExpectedValue = type(QgsFontMarkerSymbolLayer())
        mValue = type(mSymbolLayer)
        mMessage = 'Expected "%s" got "%s"' % (mExpectedValue, mValue)
        assert mExpectedValue == mValue, mMessage

        mExpectedValue = "Arial"
        mValue = mSymbolLayer.fontFamily()
        mMessage = 'Expected "%s" got "%s"' % (mExpectedValue, mValue)
        assert mExpectedValue == mValue, mMessage

        mExpectedValue = "M"
        mValue = mSymbolLayer.character()
        mMessage = 'Expected "%s" got "%s"' % (mExpectedValue, mValue)
        assert mExpectedValue == mValue, mMessage

        mExpectedValue = 6.23
        mValue = mSymbolLayer.size()
        mMessage = 'Expected "%s" got "%s"' % (mExpectedValue, mValue)
        assert mExpectedValue == mValue, mMessage

        mExpectedValue = 3
        mValue = mSymbolLayer.angle()
        mMessage = 'Expected "%s" got "%s"' % (mExpectedValue, mValue)
        assert mExpectedValue == mValue, mMessage