Adding upstream version 1.2.2.upstream/1.2.2upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 816 insertions, 0 deletions

diff --git a/share/extensions/tests/test_inkex_elements.py b/share/extensions/tests/test_inkex_elements.py
new file mode 100644
index 0000000..4844bb4
--- /dev/null
+++ b/share/extensions/tests/test_inkex_elements.py
@@ -0,0 +1,816 @@
+#!/usr/bin/env python
+# coding=utf-8
+"""
+Test specific elements API from svg xml lxml custom classes.
+"""
+
+import pytest
+import math
+import inkex
+
+from inkex import (
+    Group,
+    Layer,
+    Pattern,
+    Guide,
+    Page,
+    Polyline,
+    Use,
+    Defs,
+    TextElement,
+    TextPath,
+    Tspan,
+    FlowPara,
+    FlowRoot,
+    FlowRegion,
+    FlowSpan,
+    PathElement,
+    Rectangle,
+    Circle,
+    Ellipse,
+    Anchor,
+    Line as LineElement,
+    Transform,
+    Style,
+    LinearGradient,
+    RadialGradient,
+    Stop,
+)
+from inkex import paths
+from inkex.colors import Color
+from inkex.paths import Move, Line
+from inkex.utils import FragmentError
+from inkex.units import parse_unit
+
+from .test_inkex_elements_base import SvgTestCase
+from inkex.tester.svg import svg
+
+
+class ElementTestCase(SvgTestCase):
+    """Base element testing"""
+
+    tag = "svg"
+
+    def setUp(self):
+        super().setUp()
+        self.elem = self.svg.getElement("//svg:{}".format(self.tag))
+
+    def test_print(self):
+        """Print element as string"""
+        self.assertEqual(str(self.elem), self.tag)
+
+    def assertElement(self, elem, compare):  # pylint: disable=invalid-name
+        """Assert an element"""
+        self.assertEqual(elem.tostring(), compare)
+
+
+class PathElementTestCase(ElementTestCase):
+    """Test PathElements"""
+
+    source_file = "with-lpe.svg"
+    tag = "path"
+
+    def test_new_path(self):
+        """Test new path element"""
+        path = PathElement.new(path=[Move(10, 10), Line(20, 20)])
+        self.assertEqual(path.get("d"), "M 10 10 L 20 20")
+
+    def test_original_path(self):
+        """LPE paths can return their original paths"""
+        lpe = self.svg.getElementById("lpe")
+        nolpe = self.svg.getElementById("nolpe")
+        self.assertEqual(str(lpe.path), "M 30 30 L -10 -10 Z")
+        self.assertEqual(str(lpe.original_path), "M 20 20 L 10 10 Z")
+        self.assertEqual(str(nolpe.path), "M 30 30 L -10 -10 Z")
+        self.assertEqual(str(nolpe.original_path), "M 30 30 L -10 -10 Z")
+
+        lpe.original_path = "M 60 60 L 5 5"
+        self.assertEqual(lpe.get("inkscape:original-d"), "M 60 60 L 5 5")
+        self.assertEqual(lpe.get("d"), "M 30 30 L -10 -10 Z")
+
+        lpe.path = "M 60 60 L 15 15 Z"
+        self.assertEqual(lpe.get("d"), "M 60 60 L 15 15 Z")
+
+        nolpe.original_path = "M 60 60 L 5 5"
+        self.assertEqual(nolpe.get("inkscape:original-d", None), None)
+        self.assertEqual(nolpe.get("d"), "M 60 60 L 5 5")
+
+    def _compare_paths(self, result, reference, precision=4):
+        reference = inkex.Path(reference)
+        result = inkex.Path(result)
+        self.assertEqual(len(reference), len(result))
+        for c1, c2 in zip(reference, result):
+            self.assertEqual(c1.letter, c2.letter)
+            self.assertAlmostTuple(c1.args, c2.args, precision=precision, msg=result)
+
+    def test_arc(self):
+        """Test arc generation"""
+
+        def compare_arc(cx, cy, rx, ry, start, end, reference, type="arc"):
+            arc = PathElement.arc((cx, cy), rx, ry, start=start, end=end, arctype=type)
+            self.assertEqual(arc.get("sodipodi:arc-type"), type)
+            self._compare_paths(arc.get("d"), reference)
+
+        compare_arc(
+            10,
+            20,
+            5,
+            5,
+            math.pi / 4,
+            math.pi * 6 / 4,
+            """m 13.535534,23.535534 a 5,5 0 0 1 -6.035534,0.794593
+                       5,5 0 0 1 -2.3296291,-5.624222 5,5 0 0 1 4.8296291,-3.705905""",
+        )
+        compare_arc(
+            10,
+            20,
+            5,
+            5,
+            math.pi / 4,
+            math.pi * 6 / 4,
+            """m 13.535534,23.535534 a 5,5 0 0 1 -6.035534,0.794593
+                       5,5 0 0 1 -2.3296291,-5.624222 5,5 0 0 1 4.8296291,-3.705905 z""",
+            type="chord",
+        )
+        compare_arc(
+            10,
+            20,
+            5,
+            5,
+            math.pi / 4,
+            math.pi * 28 / 18,
+            """m 13.535534,23.535534 a 5,5 0 0 1 -6.2830789,0.641905 5,5 0 0 1 -1.8991927,-6.02347
+                       5,5 0 0 1 5.5149786,-3.078008 l -0.868241,4.924039 z""",
+            type="slice",
+        )
+
+    def test_stars(self):
+        def compare_star(
+            cx,
+            cy,
+            sides,
+            r1,
+            r2,
+            arg1,
+            arg2,
+            flatsided,
+            rounded,
+            reference,
+            precision=4,
+        ):
+            star = PathElement.star(
+                (cx, cy), (r1, r2), sides, rounded, (arg1, arg2), flatsided
+            )
+            self.assertEqual(star.get("inkscape:flatsided"), str(flatsided).lower())
+            self._compare_paths(star.get("d"), reference, precision=precision)
+
+        # Test a simple polygon
+        compare_star(
+            10,
+            5,
+            6,
+            5.5,
+            10,
+            7 / 8 * math.pi,
+            42,
+            True,
+            0,
+            """m 4.9186625,7.1047587 0.7178942,-5.4529467 5.0813373,-2.10475872
+            4.363443,3.34818802 -0.717894,5.4529467 -5.0813372,2.104759 z""",
+        )
+        # Test a star
+        compare_star(
+            5,
+            10,
+            7,
+            35,
+            17,
+            0.95545678,
+            1.4790556,
+            False,
+            0,
+            """m 25.203254,38.580212 -18.6458484,-11.651701 -11.3057927,16.6865
+           -2.5158293,-21.842628 -20.0950776,1.564637 15.508661,-15.5856099
+           -13.752359,-14.7354284 21.8548124,2.4076898 2.94616632,-19.9394165
+           11.74384528,18.5879506 17.426168,-10.1286176 -7.210477,20.7711057
+           18.783909,7.3092373 -20.735163,7.313194 z""",
+        )
+        # Test a rounded polygon
+        compare_star(
+            10,
+            5,
+            6,
+            5.5,
+            10,
+            7 / 8 * math.pi,
+            42,
+            True,
+            0.1,
+            """m 4.9186625,7.1047587 c -0.2104759,-0.5081337 0.3830754,-5.0166024 0.7178942,-5.4529467
+            0.3348188,-0.4363443 4.5360433,-2.17654814 5.0813373,-2.10475872
+            0.545295,0.0717894 4.152968,2.84005422 4.363443,3.34818802
+            0.210476,0.5081337 -0.383075,5.0166024 -0.717894,5.4529467
+            -0.334819,0.4363443 -4.5360425,2.176548 -5.0813372,2.104759
+            -0.5452947,-0.07179 -4.1529674,-2.8400545 -4.3634433,-3.3481883 z""",
+        )
+        compare_star(
+            5,
+            10,
+            7,
+            35,
+            17,
+            0.95545678,
+            1.4790556,
+            False,
+            1,
+            """m 25.203254,38.580212 c -18.8526653,11.31401 3.036933,-15.296807 -18.6458484,-11.651701
+            -19.8769816,3.341532 7.5786704,23.731873 -11.3057927,16.6865
+            -20.6000929,-7.685438 13.8530224,-7.163034 -2.5158293,-21.842628
+            -15.0056106,-13.4570388 -13.8291026,20.721824 -20.0950776,1.564637
+            -6.835231,-20.8975929 14.237504,6.364651 15.508661,-15.5856099
+            1.165291,-20.1221851 -24.823279,2.1078182 -13.752359,-14.7354284
+            12.076699,-18.3734357 3.900854,15.0996232 21.8548124,2.4076898
+            16.4587046,-11.6349155 -17.1250194,-18.0934175 2.94616632,-19.9394165
+            21.89462928,-2.013706 -9.37321772,12.464272 11.74384528,18.5879506
+            19.358377,5.61368249 3.468728,-24.6699406 17.426168,-10.1286176
+            15.225456,15.86238583 -15.589066,0.44307 -7.210477,20.7711057
+            7.680797,18.6350633 21.450453,-12.6694955 18.783909,7.3092373
+            -2.908795,21.793777 -10.066029,-11.91177319 -20.735163,7.313194
+            -9.7805797,17.623861 23.27955,8.871339 5.996985,19.243087 z""",
+            precision=2,
+        )
+
+
+class PolylineElementTestCase(ElementTestCase):
+    """Test the polyline elements support"""
+
+    tag = "polyline"
+
+    def test_type(self):
+        """Polyline have their own types"""
+        self.assertTrue(isinstance(self.elem, inkex.Polyline))
+
+    def test_polyline_points(self):
+        """Basic tests for points attribute as a path"""
+        pol = Polyline(points="10,10 50,50 10,15 15,10")
+        self.assertEqual(str(pol.path), "M 10 10 L 50 50 L 10 15 L 15 10")
+        pol.path = "M 10 10 L 30 9 L 1 2 C 10 45 3 4 45 60 M 35 35"
+        self.assertEqual(pol.get("points"), "10,10 30,9 1,2 45,60 35,35")
+
+
+class PolygonElementTestCase(ElementTestCase):
+    """Test Polygon Elements"""
+
+    tag = "polygon"
+
+    def test_type(self):
+        """Polygons have their own types"""
+        self.assertTrue(isinstance(self.elem, inkex.Polygon))
+
+    def test_conversion(self):
+        """Polygones are converted to paths"""
+        pol = inkex.Polygon(points="10,10 50,50 10,15 15,10")
+        self.assertEqual(str(pol.path), "M 10 10 L 50 50 L 10 15 L 15 10 Z")
+
+
+class LineElementTestCase(ElementTestCase):
+    """Test Line Elements"""
+
+    tag = "line"
+
+    def test_new_line(self):
+        """Line creation"""
+        line = LineElement.new((10, 10), (20, 20))
+        self.assertElement(line, b'<line x1="10.0" y1="10.0" x2="20.0" y2="20.0"/>')
+
+    def test_type(self):
+        """Lines have their own types"""
+        self.assertTrue(isinstance(self.elem, inkex.Line))
+
+    def test_conversion(self):
+        """Lines are converted to paths"""
+        pol = inkex.elements.Line(x1="2", y1="3", x2="4", y2="5")
+        self.assertEqual(str(pol.path), "M 2 3 L 4 5")
+
+
+class PatternTestCase(ElementTestCase):
+    """Test Pattern elements"""
+
+    tag = "pattern"
+
+    def test_pattern_transform(self):
+        """Patterns have a transformation of their own"""
+        pattern = Pattern()
+        self.assertEqual(pattern.patternTransform, Transform())
+        pattern.patternTransform.add_translate(10, 10)
+        self.assertEqual(pattern.get("patternTransform"), "translate(10, 10)")
+
+
+class GroupTest(ElementTestCase):
+    """Test extra functionality on a group element"""
+
+    tag = "g"
+
+    def test_new_group(self):
+        """Test creating groups"""
+        svg = Layer.new("layerA", Group.new("groupA", Rectangle()))
+        self.assertElement(
+            svg,
+            b'<g inkscape:groupmode="layer" inkscape:label="layerA">'
+            b'<g inkscape:label="groupA"><rect/></g></g>',
+        )
+
+    def test_transform_property(self):
+        """Test getting and setting a transform"""
+        self.assertEqual(
+            str(self.elem.transform), "matrix(1.44985 0 0 1.36417 -107.03 -167.362)"
+        )
+        self.elem.transform = "translate(12, 14)"
+        self.assertEqual(self.elem.transform, Transform("translate(12, 14)"))
+        self.assertEqual(str(self.elem.transform), "translate(12, 14)")
+
+    def test_groupmode(self):
+        """Get groupmode is layer"""
+        self.assertEqual(self.svg.getElementById("A").groupmode, "layer")
+        self.assertEqual(self.svg.getElementById("C").groupmode, "group")
+
+    def test_get_path(self):
+        """Group path is combined children"""
+        print(str(self.svg.getElementById("A").get_path()))
+        self.assertEqual(
+            str(self.svg.getElementById("A").get_path()),
+            "M -108.539 517.61 L -87.6093 496.117 L -98.3066 492.768 L -69.9353 492.301 L -55.5172"
+            " 506.163 L -66.2146 502.814 L -87.1446 524.307 M 60.0914 498.694 L 156.784 439.145 L"
+            " 240.218 491.183 L 143.526 550.731 z M -176.909 458.816 a 64.2385 38.9175 -7.86457 1"
+            " 0 88.3701 -19.0784 a 64.2385 38.9175 -7.86457 0 0 -88.3701 19.0784 z M -300.162"
+            " 513.715 L -282.488 509.9 Z M -214.583 540.504 L -209.001 448.77 M -193.189 547.201 "
+            "L -238.536 486.266 L -185.049 503.008 L -230.396 442.073 M -193.189 547.201 L -238.536"
+            " 486.266 L -185.049 503.008 L -230.396 442.073 Z M 15 15 L 15.5 20",
+        )
+
+    def test_bounding_box(self):
+        """A group returns a bounding box"""
+        empty = self.svg.add(Group(Group()))
+        self.assertEqual(empty.bounding_box(), None)
+        self.assertEqual(int(self.svg.getElementById("A").bounding_box().width), 783)
+        self.assertEqual(int(self.svg.getElementById("B").bounding_box().height), 114)
+
+
+class RectTest(ElementTestCase):
+    """Test extra functionality on a rectangle element"""
+
+    tag = "rect"
+
+    def test_parse(self):
+        """Test Rectangle parsed from XML"""
+        rect = Rectangle(
+            attrib={
+                "x": "10px",
+                "y": "20px",
+                "width": "100px",
+                "height": "200px",
+                "rx": "15px",
+                "ry": "30px",
+            }
+        )
+        self.assertEqual(rect.left, 10)
+        self.assertEqual(rect.top, 20)
+        self.assertEqual(rect.right, 10 + 100)
+        self.assertEqual(rect.bottom, 20 + 200)
+        self.assertEqual(rect.width, 100)
+        self.assertEqual(rect.height, 200)
+        self.assertEqual(rect.rx, 15)
+        self.assertEqual(rect.ry, 30)
+
+    def test_compose_transform(self):
+        """Composed transformation"""
+        self.assertEqual(self.elem.transform, Transform("rotate(16.097889)"))
+        self.assertEqual(
+            str(self.elem.composed_transform()),
+            "matrix(1.4019 -0.812338 1.20967 0.709877 -542.221 533.431)",
+        )
+
+    def test_effetive_stylesheet(self):
+        """Test the non-parent combination of styles"""
+        self.assertEqual(
+            str(self.elem.effective_style()), "fill:#0000ff;stroke-width:1px"
+        )
+        self.assertEqual(
+            str(self.elem.getparent().effective_style()),
+            "fill:#0000ff;stroke-width:1px;stroke:#f00",
+        )
+
+    def test_compose_stylesheet(self):
+        """Test finding the composed stylesheet for the shape"""
+        self.assertEqual(str(self.elem.style), "fill:#0000ff;stroke-width:1px")
+        self.assertEqual(
+            str(self.elem.specified_style()),
+            "fill:#0000ff;stroke-width:1px;stroke:#d88",
+        )
+
+    def test_path(self):
+        """Rectangle path"""
+        self.assertEqual(self.elem.get_path(), "M 200.0,200.0 h100.0v100.0h-100.0 z")
+        self.assertEqual(str(self.elem.path), "M 200 200 h 100 v 100 h -100 z")
+
+
+class PathTest(ElementTestCase):
+    """Test path extra functionality"""
+
+    tag = "path"
+
+    def test_apply_transform(self):
+        """Transformation can be applied to path"""
+        path = self.svg.getElementById("D")
+        path.transform = Transform(translate=(10, 10))
+        self.assertEqual(
+            path.get("d"), "M30,130 L60,130 L60,120 L70,140 L60,160 L60,150 L30,150"
+        )
+        path.apply_transform()
+        self.assertEqual(
+            path.get("d"),
+            "M 40 140 L 70 140 L 70 130 L 80 150 " "L 70 170 L 70 160 L 40 160",
+        )
+        self.assertFalse(path.transform)
+
+
+class CircleTest(ElementTestCase):
+    """Test extra functionality on a circle element"""
+
+    tag = "circle"
+
+    def test_parse(self):
+        """Test Circle parsed from XML"""
+        circle = Circle(attrib={"cx": "10px", "cy": "20px", "r": "30px"})
+        self.assertEqual(circle.center.x, 10)
+        self.assertEqual(circle.center.y, 20)
+        self.assertEqual(circle.radius, 30)
+        ellipse = Ellipse(
+            attrib={"cx": "10px", "cy": "20px", "rx": "30px", "ry": "40px"}
+        )
+        self.assertEqual(ellipse.center.x, 10)
+        self.assertEqual(ellipse.center.y, 20)
+        self.assertEqual(ellipse.radius.x, 30)
+        self.assertEqual(ellipse.radius.y, 40)
+
+    def test_new(self):
+        """Test new circles"""
+        elem = Circle.new((10, 10), 50)
+        self.assertElement(elem, b'<circle cx="10.0" cy="10.0" r="50.0"/>')
+        elem = Ellipse.new((10, 10), (15, 10))
+        self.assertElement(elem, b'<ellipse cx="10.0" cy="10.0" rx="15.0" ry="10.0"/>')
+
+    def test_path(self):
+        """Circle path"""
+        self.assertEqual(
+            self.elem.get_path(),
+            "M 100.0,50.0 a 50.0,50.0 0 1 0 50.0, "
+            "50.0 a 50.0,50.0 0 0 0 -50.0, -50.0 z",
+        )
+
+
+class AnchorTest(ElementTestCase):
+    """Test anchor tags"""
+
+    def test_new(self):
+        """Anchor tag creation"""
+        link = Anchor.new("https://inkscape.org", Rectangle())
+        self.assertElement(link, b'<a xlink:href="https://inkscape.org"><rect/></a>')
+
+
+class NamedViewTest(ElementTestCase):
+    """Test the sodipodi namedview tag"""
+
+    def test_guides(self):
+        """Create a guide and see a list of them"""
+        self.svg.namedview.add(Guide().move_to(0, 0, 0))
+        self.svg.namedview.add(Guide().move_to(0, 0, "90"))
+        self.assertEqual(len(self.svg.namedview.get_guides()), 2)
+
+    def test_guides_coincident(self):
+        """Test the detection of coincident guides"""
+
+        def coincidence_test(data, result):
+            guide1 = Guide().move_to(*data[0], angle=data[1])
+            guide2 = Guide().move_to(*data[2], angle=data[3])
+            self.assertEqual(Guide.guides_coincident(guide1, guide2), result)
+
+        # both are good
+        coincidence_test(((0, 0), (0, 1), (2, 0), (0, 3)), True)
+        # antiparallel
+        coincidence_test(((0, 0), (0, 1), (2, 0), (0, -3)), True)
+        # point not on guide
+        coincidence_test(((0, 0), (0, 1), (0, 1), (0, 3)), False)
+        # different orientation
+        coincidence_test(((0, 0), (0, 1), (2, 0), (1, 0)), False)
+        # try the same at an angle
+        coincidence_test(((1, 1), (2, -1), (3, 5), (-2, 1)), True)
+        coincidence_test(((1, 1), (2, -1), (3, 6), (-2, 1)), False)
+        # and vertical
+        coincidence_test(((0, 1), (1, 0), (0, 2), (3, 0)), True)
+        coincidence_test(((0, 1), (1, 0), (0, 2), (-3, 0)), True)
+        coincidence_test(((1, 1), (1, 0), (0, 2), (-3, 0)), False)
+
+    def test_pages(self):
+        """Create some extra pages and see a list of them"""
+        self.assertEqual(len(self.svg.namedview.get_pages()), 0)
+        self.svg.namedview.add(Page(width="210", height="297", x="0", y="0"))
+        self.svg.namedview.new_page(
+            x="220", y="0", width="147.5", height="210", label="TEST"
+        )
+        self.assertEqual(len(self.svg.namedview.get_pages()), 2)
+        self.assertEqual(self.svg.namedview.get_pages()[0].attrib["x"], "0")
+        self.assertEqual(
+            self.svg.namedview.get_pages()[1].get("inkscape:label"), "TEST"
+        )
+        self.assertEqual(self.svg.namedview.get_pages()[1].attrib["width"], "147.5")
+        self.assertEqual(self.svg.namedview.get_pages()[0].attrib["height"], "297")
+        self.assertEqual(self.svg.namedview.get_pages()[1].attrib["x"], "220")
+        self.assertEqual(self.svg.namedview.get_pages()[1].attrib["y"], "0")
+
+    def test_center(self):
+        """Test that the center in mm based documents is correctly computed"""
+        mmbased = svg(f'width="210mm" viewBox="0 0 210 297"')
+        mmbased.namedview.set(
+            "inkscape:cx", 396.57881
+        )  # Values of a freshly opened mm document
+        mmbased.namedview.set("inkscape:cy", 561.81998)
+
+        self.assertAlmostTuple(
+            mmbased.namedview.center,
+            [mmbased.viewbox_width / 2, mmbased.viewport_height / 2],
+            precision=0,
+        )
+
+
+class TextTest(ElementTestCase):
+    """Test all text functions"""
+
+    def test_append_superscript(self):
+        """Test adding superscript"""
+        tap = TextPath()
+        tap.append(Tspan.superscript("th"))
+        self.assertEqual(len(tap), 1)
+
+    def test_path(self):
+        """Test getting paths"""
+        self.assertFalse(TextPath().get_path())
+        self.assertFalse(TextElement().get_path())
+        self.assertFalse(FlowRegion().get_path())
+        self.assertFalse(FlowRoot().get_path())
+        self.assertFalse(FlowPara().get_path())
+        self.assertFalse(FlowSpan().get_path())
+        self.assertFalse(Tspan().get_path())
+
+
+class UseTest(ElementTestCase):
+    """Test extra functionality on a use element"""
+
+    tag = "use"
+
+    def test_path(self):
+        """Use path follows ref"""
+        self.assertEqual(str(self.elem.path), "M 0 0 L 10 10 Z")
+
+    def test_empty_ref(self):
+        """An empty ref or None ref doesn't cause an error"""
+        use = Use()
+        use.set("xlink:href", "something")
+        self.assertRaises(FragmentError, getattr, use, "href")
+        elem = self.svg.add(Use())
+        self.assertEqual(elem.href, None)
+        elem.set("xlink:href", "")
+        self.assertEqual(elem.href, None)
+        elem.set("xlink:href", "#badref")
+        self.assertEqual(elem.href, None)
+        elem.set("xlink:href", self.elem.get("xlink:href"))
+        self.assertEqual(elem.href.get("id"), "path1")
+
+    def test_unlink(self):
+        """Test use tag unlinking"""
+        elem = self.elem.unlink()
+        self.assertEqual(str(elem.path), "M 0 0 L 10 10 Z")
+        self.assertEqual(elem.tag_name, "path")
+        self.assertEqual(elem.getparent().get("id"), "C")
+
+    def test_unlink_xy(self):
+        """Check that unlink works if both transform and x, y are set on a clone"""
+        elem = self.svg.add(Use())
+        elem.set("xlink:href", "path1")
+        elem.set("x", "100")
+        elem.set("y", "20")
+        elem.set("transform", "rotate(20,-100,100)")
+        elem2 = elem.unlink()
+        self.assertEqual(str(elem2.path), "M 0 0 L 10 10 Z")
+        self.assertEqual(elem2.tag_name, "path")
+        self.assertAlmostTuple(
+            tuple(elem2.transform.to_hexad()),
+            tuple(inkex.Transform("rotate(20,-206.71282,373.56409)").to_hexad()),
+            3,
+        )
+
+
+class StopTests(ElementTestCase):
+    """Color stop tests"""
+
+    black = Color("#000000")
+    grey50 = Color("#080808")
+    white = Color("#111111")
+
+    def test_interpolate(self):
+        """Interpolate colours"""
+        stl1 = Style({"stop-color": self.black, "stop-opacity": 0.0})
+        stop1 = Stop(offset="0.0", style=str(stl1))
+        stl2 = Style({"stop-color": self.white, "stop-opacity": 1.0})
+        stop2 = Stop(offset="1.0", style=str(stl2))
+        stop3 = stop1.interpolate(stop2, 0.5)
+        assert stop3.style["stop-color"] == str(self.grey50)
+        assert float(stop3.style["stop-opacity"]) == pytest.approx(0.5, 1e-3)
+
+
+class GradientTests(ElementTestCase):
+    """Gradient testing"""
+
+    black = Color("#000000")
+    grey50 = Color("#080808")
+    white = Color("#111111")
+
+    whiteop1 = Style({"stop-color": white, "stop-opacity": 1.0})
+    blackop1 = Style({"stop-color": black, "stop-opacity": 1.0})
+    whiteop0 = Style({"stop-color": white, "stop-opacity": 0.0})
+    blackop0 = Style({"stop-color": black, "stop-opacity": 0.0})
+
+    translate11 = Transform("translate(1.0, 1.0)")
+    translate22 = Transform("translate(2.0, 2.0)")
+
+    def test_parse(self):
+        """Gradients parsed from XML"""
+        values = [
+            (
+                LinearGradient,
+                {"x1": "0px", "y1": "1px", "x2": "2px", "y2": "3px"},
+                {"x1": 0.0, "y1": 1.0, "x2": 2.0, "y2": 3.0},
+            ),
+            (
+                RadialGradient,
+                {"cx": "0px", "cy": "1px", "fx": "2px", "fy": "3px", "r": "4px"},
+                {"cx": 0.0, "cy": 1.0, "fx": 2.0, "fy": 3.0},
+            ),
+        ]
+        for classname, attributes, expected in values:
+            grad = classname(attrib=attributes)
+            grad.apply_transform()  # identity transform
+            for key, value in expected.items():
+                assert float(grad.get(key)) == pytest.approx(value, 1e-3)
+            grad = classname(attrib=attributes)
+
+            grad = grad.interpolate(grad, 0.0)
+            for key, value in expected.items():
+                assert float(parse_unit(grad.get(key))[0]) == pytest.approx(value, 1e-3)
+
+    def test_apply_transform(self):
+        """Transform gradients"""
+        values = [
+            (
+                LinearGradient,
+                {"x1": 0.0, "y1": 0.0, "x2": 1.0, "y2": 1.0},
+                {"x1": 1.0, "y1": 1.0, "x2": 2.0, "y2": 2.0},
+            ),
+            (
+                RadialGradient,
+                {"cx": 0.0, "cy": 0.0, "fx": 1.0, "fy": 1.0, "r": 1.0},
+                {"cx": 1.0, "cy": 1.0, "fx": 2.0, "fy": 2.0, "r": 1.0},
+            ),
+        ]
+        for classname, orientation, expected in values:
+            grad = classname().update(**orientation)
+            grad.gradientTransform = self.translate11
+            grad.apply_transform()
+            val = grad.get("gradientTransform")
+            assert val is None
+            for key, value in expected.items():
+                assert float(grad.get(key)) == pytest.approx(value, 1e-3)
+
+    def test_stops(self):
+        """Gradients have stops"""
+        for classname in [LinearGradient, RadialGradient]:
+            grad = classname()
+            stops = [
+                Stop().update(offset=0.0, style=self.whiteop0),
+                Stop().update(offset=1.0, style=self.blackop1),
+            ]
+            grad.add(*stops)
+            assert [s1.tostring() == s2.tostring() for s1, s2 in zip(grad.stops, stops)]
+
+    def test_stop_styles(self):
+        """Gradients have styles"""
+        for classname in [LinearGradient, RadialGradient]:
+            grad = classname()
+            stops = [
+                Stop().update(offset=0.0, style=self.whiteop0),
+                Stop().update(offset=1.0, style=self.blackop1),
+            ]
+            grad.add(*stops)
+            assert [str(s1) == str(s2.style) for s1, s2 in zip(grad.stop_styles, stops)]
+
+    def test_get_stop_offsets(self):
+        """Gradients stop offsets"""
+        for classname in [LinearGradient, RadialGradient]:
+            grad = classname()
+            stops = [
+                Stop().update(offset=0.0, style=self.whiteop0),
+                Stop().update(offset=1.0, style=self.blackop1),
+            ]
+            grad.add(*stops)
+            for stop1, stop2 in zip(grad.stop_offsets, stops):
+                self.assertEqual(float(stop1), pytest.approx(float(stop2.offset), 1e-3))
+
+    def test_interpolate(self):
+        """Gradients can be interpolated"""
+        values = [
+            (
+                LinearGradient,
+                {"x1": 0, "y1": 0, "x2": 1, "y2": 1},
+                {"x1": 2, "y1": 2, "x2": 1, "y2": 1},
+                {"x1": 1.0, "y1": 1.0, "x2": 1.0, "y2": 1.0},
+            ),
+            (
+                RadialGradient,
+                {"cx": 0, "cy": 0, "fx": 1, "fy": 1, "r": 0},
+                {"cx": 2, "cy": 2, "fx": 1, "fy": 1, "r": 1},
+                {"cx": 1.0, "cy": 1.0, "fx": 1.0, "fy": 1.0, "r": 0.5},
+            ),
+        ]
+        for classname, orientation1, orientation2, expected in values:
+            # gradient 1
+            grad1 = classname()
+            stops1 = [
+                Stop().update(offset=0.0, style=self.whiteop0),
+                Stop().update(offset=1.0, style=self.blackop1),
+            ]
+            grad1.add(*stops1)
+            grad1.update(gradientTransform=self.translate11)
+            grad1.update(**orientation1)
+
+            # gradient 2
+            grad2 = classname()
+            stops2 = [
+                Stop().update(offset=0.0, style=self.blackop1),
+                Stop().update(offset=1.0, style=self.whiteop0),
+            ]
+            grad2.add(*stops2)
+            grad2.update(gradientTransform=self.translate22)
+            grad2.update(**orientation2)
+            grad = grad1.interpolate(grad2, 0.5)
+            comp = Style({"stop-color": self.grey50, "stop-opacity": 0.5})
+            self.assertEqual(str(grad.stops[0].style), str(Style(comp)))
+            self.assertEqual(str(grad.stops[1].style), str(Style(comp)))
+            self.assertEqual(str(grad.gradientTransform), "translate(1.5, 1.5)")
+            for key, value in expected.items():
+                self.assertEqual(
+                    float(parse_unit(grad.get(key))[0]), pytest.approx(value, 1e-3)
+                )
+
+
+class SymbolTest(ElementTestCase):
+    """Test Symbol elements"""
+
+    source_file = "symbol.svg"
+    tag = "symbol"
+
+    def test_unlink_symbol(self):
+        """Test unlink symbols"""
+        use = self.svg.getElementById("plane01")
+        self.assertEqual(use.tag_name, "use")
+        self.assertEqual(use.href.tag_name, "symbol")
+        # Unlinking should replace symbol with group
+        elem = use.unlink()
+        self.assertEqual(elem.tag_name, "g")
+        self.assertEqual(str(elem.transform), "translate(18, 16)")
+        self.assertEqual(elem[0].tag_name, "title")
+        self.assertEqual(elem[1].tag_name, "rect")
+
+
+class DefsTest(ElementTestCase):
+    """Test the definitions tag"""
+
+    source_file = "shapes.svg"
+    tag = "defs"
+
+    def test_defs(self):
+        """Make sure defs can be seen in the nodes of an svg"""
+        self.assertTrue(isinstance(self.svg.defs, Defs))
+        defs = self.svg.getElementById("defs33")
+        self.assertTrue(isinstance(defs, Defs))
+
+
+class StyleTest(ElementTestCase):
+    """Test a style tag"""
+
+    source_file = "css.svg"
+    tag = "style"
+
+    def test_style(self):
+        """Make sure style tags can be loaded and saved"""
+        css = self.svg.stylesheet
+        self.assertTrue(css)