bsc/test: Add tests for gsm_subscriber base

This commit adds test for the generic part of gsm_subscriber like
reference counting and flag usage.

Sponsored-by: On-Waves ehf
diff --git a/openbsc/tests/testsuite.at b/openbsc/tests/testsuite.at
index ee62fa9..74aaef0 100644
--- a/openbsc/tests/testsuite.at
+++ b/openbsc/tests/testsuite.at
@@ -7,6 +7,12 @@
 AT_CHECK([$abs_top_builddir/tests/gsm0408/gsm0408_test], [], [expout], [ignore])
 AT_CLEANUP
 
+AT_SETUP([subscr])
+AT_KEYWORDS([subscr])
+cat $abs_srcdir/subscr/subscr_test.ok > expout
+AT_CHECK([$abs_top_builddir/tests/subscr/subscr_test], [], [expout], [ignore])
+AT_CLEANUP
+
 AT_SETUP([db])
 AT_KEYWORDS([db])
 cat $abs_srcdir/db/db_test.ok > expout