diff --git a/test-data/im4_float.tif b/test-data/im4_float.tif
new file mode 100644
index 000000000000..21f0e11bb096
Binary files /dev/null and b/test-data/im4_float.tif differ
diff --git a/test/functional/tools/image_diff.xml b/test/functional/tools/image_diff.xml
index a079992e5fe5..adb17639c603 100644
--- a/test/functional/tools/image_diff.xml
+++ b/test/functional/tools/image_diff.xml
@@ -22,6 +22,11 @@
       <param name="in" value="im1_uint8.png" />
       <output name="out" value="im1_uint8.png" compare="image_diff" metric="rms" eps="0" />
     </test>
+    <!-- test pair of equal images (float tiff) -->
+    <test>
+      <param name="in" value="im4_float.tif" />
+      <output name="out" value="im4_float.tif" compare="image_diff" />
+    </test>
     <!-- test pair of different images -->
     <test>
       <param name="in" value="im2_a.png" />