I noticed yesterday that the output from some integration tests running on our CI server were producing large amounts of output. It turned out that 41000 lines of the 43000 lines were coming from a single test. The reason for this is the way Specs2 handles the
contain() matcher with lists of Strings. It means that the following:
listOfIds must not(contain(badId))
is effectively the following, checking each string to see if it contains the given one:
listOfIds(0) must not(contain(badId)) listOfIds(1) must not(contain(badId)) listOfIds(2) must not(contain(badId)) ....
So if you are looking at a long list, this yields some very verbose output. With types other than String, this seems to work as expected.