pdf-test ignores error description given using as method (in AssertJ)

[cbxp]

This test:

assertThat(pdf)
   .as("My super shiny PDF report.pdf")
   .containsText("John McClane")

doesn't show the explanation My super shiny PDF report.pdf in the error message:

java.lang.AssertionError: 
Expected: a PDF containing "John McClane"
     but: was "<actual PDF content>"
Expected :a PDF containing "John McClane"
Actual   :"<actual PDF content>"