tests: Add an optional final check to checktestfg and checktestbg

Allows for the test script to specify a final check to be performed
after checking the output of the test binary. This may be useful, for
example, if the test script wants to compare logging output of the test
binary to known-good logging output.

Signed-off-by: Tyler Hicks <tyhicks@canonical.com>
Acked-by: John Johansen <john.johansen@canonical.com>

tests/regression/apparmor/prologue.inc

@@ -129,7 +129,7 @@ checktestbg()
 	then
 		echo "SIGNAL$(($rc - 128))" > $outfile
 	fi
-	checktestfg
+	checktestfg "$@"
 }
 
 runtestfg()
@@ -207,6 +207,15 @@ checktestfg()
 			;;
 	esac
 
+	if [ $# -gt 0 ]
+	then
+		$1
+		if [ "$teststatus" != "pass" ]
+		then
+			return
+		fi
+	fi
+
 	if [ -n "$VERBOSE" ]; then
 		echo "ok: ${_testdesc}"
 	fi