core implementation

code bomb implementing the bulk of the osmo-gsm-tester

Change-Id: I53610becbf643ed51b90cfd9debc6992fe211ec9
diff --git a/selftest/trial_test/invalid_checksum/file2 b/selftest/trial_test/invalid_checksum/file2
new file mode 100644
index 0000000..34ccdac
--- /dev/null
+++ b/selftest/trial_test/invalid_checksum/file2
@@ -0,0 +1 @@
+no no no