diff --git a/test/viewport.js b/test/viewport.js
index cf6b020c..063ce24d 100644
--- a/test/viewport.js
+++ b/test/viewport.js
@@ -291,6 +291,15 @@
                     testZoomLevels[i],
                     "Zoomed by the correct amount."
                 );
+
+                // now use a ref point
+                viewport.zoomBy(testZoomLevels[i], testPoints[i], true);
+                viewport.update();
+                propEqual(
+                    viewport.getZoom(),
+                    testZoomLevels[i],
+                    "Zoomed by the correct amount."
+                );
             }
 
             start();
@@ -313,6 +322,15 @@
                     testZoomLevels[i],
                     "Zoomed to the correct level."
                 );
+
+                // now use a ref point
+                viewport.zoomTo(testZoomLevels[i], testPoints[i], true);
+                viewport.update(); // need to call this even with immediately=true
+                propEqual(
+                    viewport.getZoom(),
+                    testZoomLevels[i],
+                    "Zoomed to the correct level."
+                );
             }
 
             start();