Don't remove unreferenced defs if --keep-unreferenced-defs is specified (#62)

* Don't remove unreferenced defs if `--keep-unreferenced-defs` is specified
(fixes #18)

* Add unittests for previous commit

scour/scour.py

@@ -623,7 +623,9 @@ def removeUnreferencedElements(doc, keepDefs):
    for id in identifiedElements:
       if not id in referencedIDs:
          goner = identifiedElements[id]
-         if goner != None and goner.parentNode != None and goner.nodeName in removeTags:
+         if (goner != None and goner.nodeName in removeTags
+                           and goner.parentNode != None
+                           and goner.parentNode.tagName != 'defs'):
             goner.parentNode.removeChild(goner)
             num += 1
             numElemsRemoved += 1

testscour.py

@@ -176,6 +176,35 @@ class RemoveUnreferencedElementInDefs(unittest.TestCase):
 		self.assertEqual(len(doc.getElementsByTagNameNS(SVGNS, 'rect')), 1,
 			'Unreferenced rect left in defs' )
 
+class RemoveUnreferencedDefs(unittest.TestCase):
+	def runTest(self):
+		doc = scour.scourXmlFile('unittests/unreferenced-defs.svg')
+		self.assertEqual(len(doc.getElementsByTagNameNS(SVGNS, 'linearGradient')), 1,
+			'Referenced linearGradient removed from defs' )
+		self.assertEqual(len(doc.getElementsByTagNameNS(SVGNS, 'radialGradient')), 0,
+			'Unreferenced radialGradient left in defs' )
+		self.assertEqual(len(doc.getElementsByTagNameNS(SVGNS, 'pattern')), 0,
+			'Unreferenced pattern left in defs' )
+		self.assertEqual(len(doc.getElementsByTagNameNS(SVGNS, 'rect')), 1,
+			'Referenced rect removed from defs' )
+		self.assertEqual(len(doc.getElementsByTagNameNS(SVGNS, 'circle')), 0,
+			'Unreferenced circle left in defs' )
+
+class KeepUnreferencedDefs(unittest.TestCase):
+	def runTest(self):
+		doc = scour.scourXmlFile('unittests/unreferenced-defs.svg',
+			scour.parse_args(['--keep-unreferenced-defs'])[0])
+		self.assertEqual(len(doc.getElementsByTagNameNS(SVGNS, 'linearGradient')), 1,
+			'Referenced linearGradient removed from defs with `--keep-unreferenced-defs`' )
+		self.assertEqual(len(doc.getElementsByTagNameNS(SVGNS, 'radialGradient')), 1,
+			'Unreferenced radialGradient removed from defs with `--keep-unreferenced-defs`' )
+		self.assertEqual(len(doc.getElementsByTagNameNS(SVGNS, 'pattern')), 1,
+			'Unreferenced pattern removed from defs with `--keep-unreferenced-defs`' )
+		self.assertEqual(len(doc.getElementsByTagNameNS(SVGNS, 'rect')), 1,
+			'Referenced rect removed from defs with `--keep-unreferenced-defs`' )
+		self.assertEqual(len(doc.getElementsByTagNameNS(SVGNS, 'circle')), 1,
+			'Unreferenced circle removed from defs with `--keep-unreferenced-defs`' )
+
 class DoNotRemoveChainedRefsInDefs(unittest.TestCase):
 	def runTest(self):
 		doc = scour.scourXmlFile('unittests/refs-in-defs.svg')

unittests/unreferenced-defs.svg

@@ -0,0 +1,19 @@
+<?xml version="1.0" encoding="UTF-8" standalone="no"?>
+<svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink">
+  <defs>
+    <linearGradient id="linearGradient">
+      <stop offset="0"/>
+      <stop offset="1" stop-color="blue"/>
+    </linearGradient>
+    <radialGradient id="radialGradient">
+      <stop offset="0"/>
+      <stop offset="1" stop-color="blue"/>
+    </radialGradient>
+    <pattern id="pattern">
+      <polygon fill="none" points="71.125,-1.896 2.125,-1.896 2.125,-70.896 71.125,-70.896"/>
+    </pattern>
+    <rect id="rect" width="50" height="50"/>
+    <circle id="circle" width="100" height="100"/>
+  </defs>
+  <use x="10" y="10" xlink:href="#rect" fill="url(#linearGradient)"/>
+</svg>