diff --git a/test/testdata/model.xml b/test/testdata/model.xml
index 8f1f16fe..5256859c 100644
--- a/test/testdata/model.xml
+++ b/test/testdata/model.xml
@@ -161,4 +161,13 @@
          qpos="0.0133625 -0.013799 0.659429 0.999776 0.019159 0.00902704 0.000572574 -0.00776575 0.0983289 0.999861 -0.00869796 -0.0141805 0.000912197 0.00700633 0.0930296 0.00637469 -0.00313231 0.119692 0.0051478 -0.0469067 0 -0.500224 0.300659 0.69913 1 -0.000367766 -0.000265698 -0.000109715 -0.319851 0.525628 0.702735 0.29858 0.698263 -0.0490604 -0.648746 -0.579432 0.4206 0.749601 0.900145 -0.208463 0.346664 -0.161576 -0.200033 0.300084 0.976421 0.878429 -0.00171382 0.00127086 -0.477867"
          qvel="0.508861 -0.243772 -0.327162 0.549686 1.13746 0.0282475 -0.0865243 1.06414 -0.239958 -0.532111 -0.00133789 -0.0654491 0.533148 -0.253161 0.122149 0.824764 0.723529 -0.674175 0 -0.00154509 -0.00568917 0.00479921 0.00541817 0.00115895 0.00317796 -0.160161 -0.599488 -1.38103 14.9789 -1.05454 -13.9252 -0.31223 -0.0102486 -0.405851 5.43992 -4.71514 0.114928 -0.00123758 0.000187845 -0.244109 -0.190199 0.0697975 -16.3286"/>
   </keyframe>
+
+  <custom>
+    <numeric name="numeric" data="1 2 3"/>
+    <text name="text" data="abc"/>
+    <tuple name="tuple">
+      <element objtype="body" objname="cylinder" prm="1"/>
+      <element objtype="joint" objname="hipz_0" prm="2"/>
+    </tuple>
+  </custom>
 </mujoco>