Auto merge of #4181 - gilescope:patch-1, r=alexcrichton
Auto merge of #4181 - gilescope:patch-1, r=alexcrichton

Make test less brittle prior to assert_eq failure message format change

PR required for rust-lang/rust#42541 to make assert_eq error message be multi-line. Before implementing this we need to make the current test less brittle.
Not 100% clear on if I need the final [...] or not.

rustyhorde/cargo,tshepang/cargo,tsurai/cargo,durka/cargo,rust-lang/cargo,rustyhorde/cargo,eminence/cargo,tsurai/cargo,vojtechkral/cargo,eminence/cargo,eminence/cargo,rustyhorde/cargo,achanda/cargo,tsurai/cargo,nipunn1313/cargo,durka/cargo,rust-lang/cargo,rust-lang/cargo,rustyhorde/cargo,durka/cargo,vojtechkral/cargo,vojtechkral/cargo,vojtechkral/cargo,rust-lang/cargo,achanda/cargo,nipunn1313/cargo,eminence/cargo,nipunn1313/cargo,durka/cargo,achanda/cargo,nipunn1313/cargo,tsurai/cargo,tshepang/cargo,achanda/cargo,tshepang/cargo,tsurai/cargo,tshepang/cargo