V.42bis: integration and unit test

 - Edit previously committed V.42bis implementation to function
   outside IAXmodem.
 - Add unit test to verify the correct function of V.42bis

Change-Id: I689413f2541b6def0625ce6bd96f1f488f05f99d
diff --git a/openbsc/tests/testsuite.at b/openbsc/tests/testsuite.at
index 5f37b8e..f18b734 100644
--- a/openbsc/tests/testsuite.at
+++ b/openbsc/tests/testsuite.at
@@ -141,3 +141,9 @@
 cat $abs_srcdir/slhc/slhc_test.ok > expout
 AT_CHECK([$abs_top_builddir/tests/slhc/slhc_test], [], [expout], [ignore])
 AT_CLEANUP
+
+AT_SETUP([v42bis])
+AT_KEYWORDS([v42bis])
+cat $abs_srcdir/v42bis/v42bis_test.ok > expout
+AT_CHECK([$abs_top_builddir/tests/v42bis/v42bis_test], [], [expout], [ignore])
+AT_CLEANUP