testUrl method error: | separator urlencoded

I get the following error, it seems the | separator comes urlencoded:

Failed asserting that two strings are equal.
--- Expected
+++ Actual
@@ @@
-'/images/display/1/thumbnail:width|200;height|150/hash:69aa9f46cdc5a200dc7539fc10eec00f2ba89023'
+'/images/display/1/thumbnail:width%7C200%3Bheight%7C150/hash:69aa9f46cdc5a200dc7539fc10eec00f2ba89023'