tests: Use GNU autotest to execute our tests and compare textual output
The output of make check is looking like this now:
Regression tests.
1: bits ok
2: msgfile ok
3: sms ok
4: smscb ok
5: timer FAILED (testsuite.at:38)
6: ussd FAILED (testsuite.at:44)
diff --git a/tests/bits/bitrev_test.ok b/tests/bits/bitrev_test.ok
new file mode 100644
index 0000000..47f402f
--- /dev/null
+++ b/tests/bits/bitrev_test.ok
@@ -0,0 +1,24 @@
+INORDER: 01 02 04 08 10 20 40 80
+REVERSED: 80 40 20 10 08 04 02 01
+
+INORDER: 02 04 08 10 20 40 80
+REVERSED: 40 20 10 08 04 02 01
+
+INORDER: 04 08 10 20 40 80
+REVERSED: 20 10 08 04 02 01
+
+INORDER: 08 10 20 40 80
+REVERSED: 10 08 04 02 01
+
+INORDER: 10 20 40 80
+REVERSED: 08 04 02 01
+
+INORDER: 20 40 80
+REVERSED: 04 02 01
+
+INORDER: 40 80
+REVERSED: 02 01
+
+INORDER: 80
+REVERSED: 01
+