Include a test of the get_parent method

tests/data/refs/sis__4a1ab1abe69fa027d5038c0ebb71073d.out

@@ -0,0 +1,13 @@
+<!-- Created with Inkscape (http://www.inkscape.org/) --><svg xmlns="http://www.w3.org/2000/svg" xmlns:sodipodi="http://sodipodi.sourceforge.net/DTD/sodipodi-0.dtd" xmlns:inkscape="http://www.inkscape.org/namespaces/inkscape" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" xmlns:cc="http://web.resource.org/cc/" xmlns:dc="http://purl.org/dc/elements/1.1/" width="793.7007874" height="1122.519685">
+  <defs/>
+  <sodipodi:namedview id="base" pagecolor="#ffffff" bordercolor="#666666" borderopacity="1.0" inkscape:pageopacity="0.0" inkscape:pageshadow="2" inkscape:zoom="0.35" inkscape:cx="375" inkscape:cy="520" inkscape:document-units="px" inkscape:current-layer="layer1"/>
+  <metadata>
+    <rdf:RDF>
+      <cc:Work rdf:about="">
+        <dc:format>image/svg+xml</dc:format>
+        <dc:type rdf:resource="http://purl.org/dc/dcmitype/StillImage"/>
+      </cc:Work>
+    </rdf:RDF>
+  </metadata>
+  <g inkscape:label="Layer 1" inkscape:groupmode="layer" id="layer1"><g><circle cx="40" cy="20" r="8" style="stroke:black;fill:red"/><circle cx="60" cy="20" r="8" style="stroke:black;fill:red"/><circle cx="80" cy="20" r="8" style="stroke:black;fill:red"/><circle cx="100" cy="20" r="8" style="stroke:black;fill:red"/></g><g><circle cx="20" cy="40" r="8" style="stroke:black;fill:orange"/><circle cx="60" cy="40" r="8" style="stroke:black;fill:orange"/><circle cx="80" cy="40" r="8" style="stroke:black;fill:orange"/><circle cx="100" cy="40" r="8" style="stroke:black;fill:orange"/></g><g><circle cx="20" cy="60" r="8" style="stroke:black;fill:yellow"/><circle cx="40" cy="60" r="8" style="stroke:black;fill:yellow"/><circle cx="80" cy="60" r="8" style="stroke:black;fill:yellow"/><circle cx="100" cy="60" r="8" style="stroke:black;fill:yellow"/></g><g><circle cx="20" cy="80" r="8" style="stroke:black;fill:green"/><circle cx="40" cy="80" r="8" style="stroke:black;fill:green"/><circle cx="60" cy="80" r="8" style="stroke:black;fill:green"/><circle cx="100" cy="80" r="8" style="stroke:black;fill:green"/></g><g><circle cx="20" cy="100" r="8" style="stroke:black;fill:blue"/><circle cx="40" cy="100" r="8" style="stroke:black;fill:blue"/><circle cx="60" cy="100" r="8" style="stroke:black;fill:blue"/><circle cx="80" cy="100" r="8" style="stroke:black;fill:blue"/></g><g transform="translate(120, 0)"><circle cx="20" cy="20" r="8" style="stroke:black;fill:red"/><circle cx="40" cy="40" r="8" style="stroke:black;fill:orange"/><circle cx="60" cy="60" r="8" style="stroke:black;fill:yellow"/><circle cx="80" cy="80" r="8" style="stroke:black;fill:green"/><circle cx="100" cy="100" r="8" style="stroke:black;fill:blue"/></g></g>
+</svg>

tests/test_simple_inkscape_scripting.py

@@ -149,6 +149,37 @@ class SimpInkScrTestCommonArgs(CustomComparisonMixin,
     compare_file = 'svg/default-inkscape-SVG.svg'
 
 
+class SimpInkScrTestCollections(CustomComparisonMixin,
+                                InkscapeExtensionTestMixin,
+                                TestCase):
+    'Test examples from the Object Collections wiki page.'
+    # Indicate how testing should be performed.
+    effect_class = SimpleInkscapeScripting
+    compare_filters = [CompareOrderIndependentStyle()]
+
+    # Define a sequence of tests.
+    comparisons = [
+        ('''--program=
+colors = ['red', 'orange', 'yellow', 'green', 'blue']
+diag = []
+for j in range(5):
+    gr = group()
+    for i in range(5):
+        c = circle((i*20 + 20, j*20 + 20), 8, fill=colors[j])
+        gr.append(c)
+        if i == j:
+            diag.append(c)
+
+diag_gr = group()
+for c in diag:
+    c.get_parent().ungroup(c)
+    diag_gr.append(c)
+diag_gr.translate((120, 0))
+''',)
+    ]
+    compare_file = 'svg/default-inkscape-SVG.svg'
+
+
 class SimpInkScrTestEffects(CustomComparisonMixin,
                             InkscapeExtensionTestMixin,
                             TestCase):