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+<svg xmlns="http://www.w3.org/2000/svg"
+     xmlns:xlink="http://www.w3.org/1999/xlink"
+     class="reftest-wait"
+     onload="go()">
+  <!-- Instance time filtering involves removing instance times that are no
+       longer needed. However, under some arrangements an excessive number of
+       instance times may be generated that will never be cleaned up since they
+       might potentially still affect the behavior of the timing model.
+       
+       For example, consider the case where we have a valid cyclic dependency
+       (e.g.  a ping-pong effect) between TimeEvents. For example,
+       a.begin=b.endEvent and b.begin=a.endEvent. The times generated by this
+       arrangement won't be cleared by regular filtering since they're
+       technically unpredictable (e.g. seeking the document will cause some
+       events to be suppressed) and so we preserve them to provide correct
+       backwards seeking support.
+
+       Therefore, after reaching a certain threshold, old instance times are
+       simply discarded indiscriminantly to avoid consuming memory in unbounded
+       fashion as the animation progresses.
+
+       This test checks this second stage of instance time filtering. -->
+  <script>
+    function go() {
+      var svg = document.documentElement;
+      var anim = document.getElementById('anim');
+
+      // To begin with we have an animation from 0s-2s
+      svg.pauseAnimations();
+      svg.setCurrentTime(1.0); // Seek to mid-interval
+
+      // Generate a lot of instance times beyond the interval end at t=2s
+      // The threshold will be something like 100 but just in case it's 200
+      // let's make 210 instance times.
+      for (var i = 0; i &lt; 210; i++) {
+        // The first instance time will be at t=3s and then we'll generate lots
+        // of times following on from there
+        anim.beginElementAt(2 + i * 0.1);
+      }
+
+      // Seek past the interval end -- this will cause the filtering to kick in.
+      // The first stage of filtering will only filter instance times before the
+      // end of the previous interval (i.e. before t=2s in this case).
+      // The second stage of filtering should take care of the rest.
+      svg.setCurrentTime(2.5);
+
+      // The second stage of filtering will clear out the oldest times first.
+      // However, since first time we generated at t=3s is now used as begin of
+      // the yet-to-begin current interval it should not be cleared.
+      // So if we force the current interval to be updated by adding another
+      // instance time the next interval should still start at t=3s.
+      anim.beginElementAt(100);
+
+      // Now when we go to do a snapshot at t=3s, the animation should be in
+      // effect.
+      svg.setCurrentTime(3.0);
+      svg.removeAttribute("class");
+    }
+  </script>
+  <rect id="blueRect" x="100" y="15" width="200" height="200" fill="blue">
+    <set id="anim" attributeName="x" to="15" begin="0s" dur="2s"/>
+  </rect>
+</svg>