diff --git a/Tests/designspaceLib/data/test.designspace b/Tests/designspaceLib/data/test.designspace
index cf7056b33..9f97ab57c 100644
--- a/Tests/designspaceLib/data/test.designspace
+++ b/Tests/designspaceLib/data/test.designspace
@@ -1,107 +1,111 @@
-<?xml version='1.0' encoding='utf-8'?>
+<?xml version='1.0' encoding='UTF-8'?>
 <designspace format="4.0">
-    <axes>
-        <axis default="0" maximum="1000" minimum="0" name="weight" tag="wght">
-            <labelname xml:lang="en">Wéíght</labelname>
-            <labelname xml:lang="fa-IR">قطر</labelname>
-        </axis>
-        <axis default="20" hidden="1" maximum="1000" minimum="0" name="width" tag="wdth">
-            <labelname xml:lang="fr">Chasse</labelname>
-            <map input="0" output="10" />
-            <map input="401" output="66" />
-            <map input="1000" output="990" />
-        </axis>
-    </axes>
-    <rules>
-        <rule name="named.rule.1">
-            <conditionset>
-                <condition maximum="1" minimum="0" name="axisName_a" />
-                <condition maximum="3" minimum="2" name="axisName_b" />
-            </conditionset>
-            <sub name="a" with="a.alt" />
-        </rule>
-    </rules>
-    <sources>
-        <source familyname="MasterFamilyName" filename="masters/masterTest1.ufo" name="master.ufo1" stylename="MasterStyleNameOne">
-            <lib copy="1" />
-            <features copy="1" />
-            <info copy="1" />
-            <glyph mute="1" name="A" />
-            <glyph mute="1" name="Z" />
-            <location>
-                <dimension name="weight" xvalue="0" />
-                <dimension name="width" xvalue="20" />
-            </location>
-        </source>
-        <source familyname="MasterFamilyName" filename="masters/masterTest2.ufo" name="master.ufo2" stylename="MasterStyleNameTwo">
-            <kerning mute="1" />
-            <location>
-                <dimension name="weight" xvalue="1000" />
-                <dimension name="width" xvalue="20" />
-            </location>
-        </source>
-        <source familyname="MasterFamilyName" filename="masters/masterTest2.ufo" layer="supports" name="master.ufo2" stylename="Supports">
-            <location>
-                <dimension name="weight" xvalue="1000" />
-                <dimension name="width" xvalue="20" />
-            </location>
-        </source>
-    </sources>
-    <instances>
-        <instance familyname="InstanceFamilyName" filename="instances/instanceTest1.ufo" name="instance.ufo1" postscriptfontname="InstancePostscriptName" stylemapfamilyname="InstanceStyleMapFamilyName" stylemapstylename="InstanceStyleMapStyleName" stylename="InstanceStyleName">
-            <location>
-                <dimension name="weight" xvalue="500" />
-                <dimension name="width" xvalue="20" />
-            </location>
-            <glyphs>
-                <glyph mute="1" name="arrow" unicode="0x123 0x124 0x125" />
-            </glyphs>
-            <kerning />
-            <info />
-            <lib>
-                <dict>
-                    <key>com.coolDesignspaceApp.specimenText</key>
-                    <string>Hamburgerwhatever</string>
-                </dict>
-            </lib>
-        </instance>
-        <instance familyname="InstanceFamilyName" filename="instances/instanceTest2.ufo" name="instance.ufo2" postscriptfontname="InstancePostscriptName" stylemapfamilyname="InstanceStyleMapFamilyName" stylemapstylename="InstanceStyleMapStyleName" stylename="InstanceStyleName">
-            <location>
-                <dimension name="weight" xvalue="500" />
-                <dimension name="width" xvalue="400" yvalue="300" />
-            </location>
-            <glyphs>
-                <glyph name="arrow" unicode="0x65 0xc9 0x12d">
-                    <location>
-                        <dimension name="weight" xvalue="120" />
-                        <dimension name="width" xvalue="100" />
-                    </location>
-                    <note>A note about this glyph</note>
-                    <masters>
-                        <master glyphname="BB" source="master.ufo1">
-                            <location>
-                                <dimension name="weight" xvalue="20" />
-                                <dimension name="width" xvalue="20" />
-                            </location>
-                        </master>
-                        <master glyphname="CC" source="master.ufo2">
-                            <location>
-                                <dimension name="weight" xvalue="900" />
-                                <dimension name="width" xvalue="900" />
-                            </location>
-                        </master>
-                    </masters>
-                </glyph>
-                <glyph name="arrow2" />
-            </glyphs>
-            <kerning />
-            <info />
-        </instance>
-    </instances>
-    <lib>
+  <axes>
+    <axis tag="wght" name="weight" minimum="0" maximum="1000" default="0">
+      <labelname xml:lang="en">Wéíght</labelname>
+      <labelname xml:lang="fa-IR">قطر</labelname>
+    </axis>
+    <axis tag="wdth" name="width" minimum="0" maximum="1000" default="20" hidden="1">
+      <labelname xml:lang="fr">Chasse</labelname>
+      <map input="0" output="10"/>
+      <map input="401" output="66"/>
+      <map input="1000" output="990"/>
+    </axis>
+  </axes>
+  <rules>
+    <rule name="named.rule.1">
+      <conditionset>
+        <condition name="axisName_a" minimum="0" maximum="1"/>
+        <condition name="axisName_b" minimum="2" maximum="3"/>
+      </conditionset>
+      <sub name="a" with="a.alt"/>
+    </rule>
+  </rules>
+  <sources>
+    <source filename="masters/masterTest1.ufo" name="master.ufo1" familyname="MasterFamilyName" stylename="MasterStyleNameOne">
+      <lib copy="1"/>
+      <features copy="1"/>
+      <info copy="1"/>
+      <glyph name="A" mute="1"/>
+      <glyph name="Z" mute="1"/>
+      <location>
+        <dimension name="weight" xvalue="0"/>
+        <dimension name="width" xvalue="20"/>
+      </location>
+    </source>
+    <source filename="masters/masterTest2.ufo" name="master.ufo2" familyname="MasterFamilyName" stylename="MasterStyleNameTwo">
+      <kerning mute="1"/>
+      <location>
+        <dimension name="weight" xvalue="1000"/>
+        <dimension name="width" xvalue="20"/>
+      </location>
+    </source>
+    <source filename="masters/masterTest2.ufo" name="master.ufo2" familyname="MasterFamilyName" stylename="Supports" layer="supports">
+      <location>
+        <dimension name="weight" xvalue="1000"/>
+        <dimension name="width" xvalue="20"/>
+      </location>
+    </source>
+  </sources>
+  <instances>
+    <instance name="instance.ufo1" familyname="InstanceFamilyName" stylename="InstanceStyleName" filename="instances/instanceTest1.ufo" postscriptfontname="InstancePostscriptName" stylemapfamilyname="InstanceStyleMapFamilyName" stylemapstylename="InstanceStyleMapStyleName">
+      <location>
+        <dimension name="weight" xvalue="500"/>
+        <dimension name="width" xvalue="20"/>
+      </location>
+      <glyphs>
+        <glyph mute="1" unicode="0x123 0x124 0x125" name="arrow"/>
+      </glyphs>
+      <kerning/>
+      <info/>
+      <lib>
         <dict>
-            <key>com.coolDesignspaceApp.previewSize</key>
-            <integer>30</integer>
+          <key>com.coolDesignspaceApp.binaryData</key>
+          <data>
+          PGJpbmFyeSBndW5rPg==
+          </data>
+          <key>com.coolDesignspaceApp.specimenText</key>
+          <string>Hamburgerwhatever</string>
         </dict>
-    </lib>
+      </lib>
+    </instance>
+    <instance name="instance.ufo2" familyname="InstanceFamilyName" stylename="InstanceStyleName" filename="instances/instanceTest2.ufo" postscriptfontname="InstancePostscriptName" stylemapfamilyname="InstanceStyleMapFamilyName" stylemapstylename="InstanceStyleMapStyleName">
+      <location>
+        <dimension name="weight" xvalue="500"/>
+        <dimension name="width" xvalue="400" yvalue="300"/>
+      </location>
+      <glyphs>
+        <glyph unicode="0x65 0xc9 0x12d" name="arrow">
+          <location>
+            <dimension name="weight" xvalue="120"/>
+            <dimension name="width" xvalue="100"/>
+          </location>
+          <note>A note about this glyph</note>
+          <masters>
+            <master glyphname="BB" source="master.ufo1">
+              <location>
+                <dimension name="weight" xvalue="20"/>
+                <dimension name="width" xvalue="20"/>
+              </location>
+            </master>
+            <master glyphname="CC" source="master.ufo2">
+              <location>
+                <dimension name="weight" xvalue="900"/>
+                <dimension name="width" xvalue="900"/>
+              </location>
+            </master>
+          </masters>
+        </glyph>
+        <glyph name="arrow2"/>
+      </glyphs>
+      <kerning/>
+      <info/>
+    </instance>
+  </instances>
+  <lib>
+    <dict>
+      <key>com.coolDesignspaceApp.previewSize</key>
+      <integer>30</integer>
+    </dict>
+  </lib>
 </designspace>
diff --git a/Tests/designspaceLib/designspace_test.py b/Tests/designspaceLib/designspace_test.py
index 1d9b841a7..f17e129f7 100644
--- a/Tests/designspaceLib/designspace_test.py
+++ b/Tests/designspaceLib/designspace_test.py
@@ -123,6 +123,7 @@ def test_fill_document(tmpdir):
     i1.styleMapStyleName = "InstanceStyleMapStyleName"
     glyphData = dict(name="arrow", mute=True, unicodes=[0x123, 0x124, 0x125])
     i1.glyphs['arrow'] = glyphData
+    i1.lib['com.coolDesignspaceApp.binaryData'] = b'<binary gunk>'
     i1.lib['com.coolDesignspaceApp.specimenText'] = "Hamburgerwhatever"
     doc.addInstance(i1)
     # add instance 2