Add end-to-end Test

- Add an infrastructur to run local e2e tests.
- Add some tests.

e2e-tests/tests/21_simple_not_encrypt.sh

@@ -0,0 +1,25 @@
+#!/usr/bin/bash
+
+echo "Simple: Test encryption for unavailable certificate"
+
+# There is no authenticated certificate for alice in the cert store
+adduser --shell /bin/bash --disabled-password --gecos "" alice
+echo "test mail" | sendmail alice@example.com
+
+sleep 1
+
+if [ -f /var/mail/alice ] ; then
+  if grep -q "BEGIN PGP MESSAGE" /var/mail/alice ; then
+    echo "encryption detected - that is wrong"
+    RESULT_CODE=1
+  else
+    RESULT_CODE=0
+  fi
+else
+  echo "no mail detected"
+  RESULT_CODE=1 
+fi
+
+deluser --remove-home alice
+
+exit $RESULT_CODE