add test for aptget source for unavailable package

test/integration/test-apt-get-source

@@ -53,3 +53,8 @@ Need to get 0 B of source archives.
 'file://${APTARCHIVE}/foo_0.1.dsc' foo_0.1.dsc 0 MD5Sum:d41d8cd98f00b204e9800998ecf8427e
 'file://${APTARCHIVE}/foo_0.1.tar.gz' foo_0.1.tar.gz 0 MD5Sum:d41d8cd98f00b204e9800998ecf8427e" aptget source -q --print-uris foo/wheezy
 
+# unavailable one
+testequal "$HEADER
+E: Ignore unavailable version '9.9-not-there' of package 'foo'
+E: Unable to find a source package for foo" aptget source -q --print-uris foo=9.9-not-there
+