add test script

README.md

@@ -51,3 +51,13 @@ self-signed CA.
   - The CA cert will be valid for 3650 days (10 years).
   - The server cert will be valid for 365 days (1 year).
   - The x509 certs are ECDSA with prime256v1 curve and SHA256 signatures.
+
+## Testing
+
+I have added a simplistic script [testme.sh](testme.sh) that helps to test this
+script in the following  Linux distributions:
+
+- Alpine 3.7
+- Ubuntu Bionic
+- Debian Stretch
+- CentOS 7

testme.sh

@@ -0,0 +1,18 @@
+#!/bin/bash
+set -e
+
+TMPDIR="$(mktemp -d)"
+cp -v gencert.sh "${TMPDIR}/"
+pushd "${TMPDIR}"
+
+for DISTRO in alpine:3.7 ubuntu:bionic debian:stretch centos:7; do
+  printf "\n\n\nTesting the script with ${DISTRO} ...\n\n\n"
+  rm -vf openssl.cnf private.key public.crt ca.crt ca.key ca.srl
+  docker run --rm -ti -v ${PWD}:/w -w /w ${DISTRO} sh gencert.sh --cn test.example.com
+  printf "\n\n\n"
+done
+
+popd
+echo "WARNING, I am going to remove ${TMPDIR} entirely in 5 seconds!"
+sleep 5
+rm -rf "${TMPDIR}"