Add docker-based test scripts

Enable running tests under Docker. This makes it easier to spin up an
environment with all dependencies (especially the multiple versions of
openssl and gnutls needed).
* tests/docker/xenial/Dockerfile: Definition for the docker image,
  including local builds for openssl and gnutls.
* tests/scripts/docker_env.sh: New helper script that creates the Docker
  image and has a function to run a command in the Docker container.
* tests/docker/all-in-docker.sh: Wrapper for all.sh under Docker.
* tests/docker/basic-in-docker.sh: Script that runs the same commands as
  .travis.yml, in Docker.
* tests/ssl-opt-in-docker.sh: Wrapper to run ssl-opt.sh in Docker.
* tests/compat-in-docker.sh: Wrapper to run compat.sh in Docker.
* tests/make-in-docker.sh: Wrapper to run make in Docker.

Change-Id: Ie092b1deed24c24c3859754535589523ce1d0a58

tests/scripts/docker_env.sh

@@ -0,0 +1,75 @@
+#!/bin/bash -eu
+
+# docker_env.sh
+#
+# This file is part of mbed TLS (https://tls.mbed.org)
+#
+# Copyright (c) 2018-2019, ARM Limited, All Rights Reserved
+#
+# Purpose
+# -------
+#
+# This is a helper script to enable running tests under a Docker container,
+# thus making it easier to get set up as well as isolating test dependencies
+# (which include legacy/insecure configurations of openssl and gnutls).
+#
+# Notes for users
+# ---------------
+# This script expects a Linux x86_64 system with a recent version of Docker
+# installed and available for use, as well as http/https access. If a proxy
+# server must be used, invoke this script with the usual environment variables
+# (http_proxy and https_proxy) set appropriately.
+#
+# Running this script directly will check for Docker availability and set up
+# the Docker image.
+
+
+# default values, can be overridden by the environment
+: ${MBEDTLS_DOCKER_GUEST:=xenial}
+
+
+DOCKER_IMAGE_TAG="armmbed/mbedtls-test:${MBEDTLS_DOCKER_GUEST}"
+
+# Make sure docker is available
+if ! which docker > /dev/null; then
+    echo "Docker is required but doesn't seem to be installed. See https://www.docker.com/ to get started"
+    exit 1
+fi
+
+# Figure out if we need to 'sudo docker'
+if groups | grep docker > /dev/null; then
+    DOCKER="docker"
+else
+    echo "Using sudo to invoke docker since you're not a member of the docker group..."
+    DOCKER="sudo docker"
+fi
+
+# Build the Docker image
+echo "Getting docker image up to date (this may take a few minutes)..."
+${DOCKER} image build \
+    -t ${DOCKER_IMAGE_TAG} \
+    --cache-from=${DOCKER_IMAGE_TAG} \
+    --build-arg MAKEFLAGS_PARALLEL="-j $(nproc)" \
+    ${http_proxy+--build-arg http_proxy=${http_proxy}} \
+    ${https_proxy+--build-arg https_proxy=${https_proxy}} \
+    tests/docker/${MBEDTLS_DOCKER_GUEST}
+
+run_in_docker()
+{
+    ENV_ARGS=""
+    while [ "$1" == "-e" ]; do
+        ENV_ARGS="${ENV_ARGS} $1 $2"
+        shift 2
+    done
+
+    ${DOCKER} container run -it --rm \
+        --cap-add SYS_PTRACE \
+        --user "$(id -u):$(id -g)" \
+        --volume $PWD:$PWD \
+        --workdir $PWD \
+        -e MAKEFLAGS \
+        -e PYLINTHOME=/tmp/.pylintd \
+        ${ENV_ARGS} \
+        ${DOCKER_IMAGE_TAG} \
+        $@
+}