add an additional test for arch specific conflicts

In bugreport #747261 I confirmed with this testcase that apt actually
supports the requested architecture-specific conflicts already since
2012 with commit cef094c2ec8214b2783a2ac3aa70cf835381eae1.

The old test only does simulations which are handy to check apt,
this one builds 'real' packages to see if dpkg agrees with us.

Git-Dch: Ignore

test/integration/test-bug-747261-arch-specific-conflicts

@@ -0,0 +1,36 @@
+#!/bin/sh
+set -e
+
+TESTDIR=$(readlink -f $(dirname $0))
+. $TESTDIR/framework
+setupenvironment
+configarchitecture 'amd64' 'sparc' 'armel'
+
+buildsimplenativepackage 'libc6' 'amd64,sparc,armel' '1' 'stable' 'Multi-Arch: same'
+buildsimplenativepackage 'libc6-i386' 'amd64' '1' 'stable' 'Conflicts: libc6:sparc'
+
+setupaptarchive
+
+testsuccess aptget install 'libc6:amd64' 'libc6:sparc' -y
+testdpkginstalled 'libc6:amd64' 'libc6:sparc'
+testdpkgnotinstalled 'libc6-i386' 'libc6:armel'
+
+testsuccess aptget install libc6-i386 -y
+testdpkginstalled 'libc6:amd64' 'libc6-i386'
+testdpkgnotinstalled 'libc6:sparc' 'libc6:armel'
+
+testsuccess aptget install libc6:armel -y
+testdpkginstalled 'libc6:amd64' 'libc6:armel' 'libc6-i386'
+testdpkgnotinstalled 'libc6:sparc'
+
+testsuccess aptget install libc6:sparc -y
+testdpkginstalled 'libc6:amd64' 'libc6:armel' 'libc6:sparc'
+testdpkgnotinstalled 'libc6-i386'
+
+testsuccess aptget purge 'libc6:*' 'libc6-i386' -y
+testdpkgnotinstalled 'libc6:amd64' 'libc6:armel' 'libc6:sparc' 'libc6-i386'
+
+# check that (the actually simpler) single arch is fine, too
+configarchitecture 'amd64'
+testfailure aptget install libc6:sparc -s
+testsuccess aptget install libc6 libc6-i386 -y