implement a more generic ShowList method

apt-get is displaying various lists of package names, which until now it
was building as a string before passing it to ShowList, which inserted
linebreaks at fitting points and showed a title if needed, but it never
really understood what it was working with. With the help of C++11 the
new generic knows not only what it works with, but generates the list on
the fly rather than asking for it and potentially discarding parts of
the input (= the non-default verbose display). It also doubles as a test
for how usable the CacheSets are with C++11.

(Not all callers are adapted yet.)

Git-Dch: Ignore

1 files changed, 14 insertions, 0 deletions

diff --git a/test/integration/test-bug-675449-essential-are-protected b/test/integration/test-bug-675449-essential-are-protected
index f50507532..e62add938 100755
--- a/test/integration/test-bug-675449-essential-are-protected
+++ b/test/integration/test-bug-675449-essential-are-protected
@@ -87,3 +87,17 @@ Inst pkg-none-native [1] (2 unstable [amd64])
 Conf pkg-none-native (2 unstable [amd64])
 Inst pkg-none-new (2 unstable [amd64])
 Conf pkg-none-new (2 unstable [amd64])' aptget dist-upgrade -s
+
+insertinstalledpackage 'foo' 'amd64' '1' 'Depends: libfoo
+Essential: yes'
+insertinstalledpackage 'libfoo' 'amd64' '1'
+testequal 'Reading package lists...
+Building dependency tree...
+The following packages will be REMOVED:
+  foo* libfoo*
+WARNING: The following essential packages will be removed.
+This should NOT be done unless you know exactly what you are doing!
+  foo libfoo (due to foo)
+0 upgraded, 0 newly installed, 2 to remove and 4 not upgraded.
+Purg foo [1]
+Purg libfoo [1]' aptget purge libfoo -s