Add integration testing

__test__/integration-tests.sh

@@ -0,0 +1,23 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+IMAGE="cpr-integration-tests:latest"
+ARG1=${1:-}
+
+if [[ "$(docker images -q $IMAGE 2> /dev/null)" == "" || $ARG1 == "build" ]]; then
+    echo "Building Docker image $IMAGE ..."
+
+    cat > Dockerfile << EOF
+FROM node:12-alpine
+RUN apk --no-cache add git git-daemon
+RUN npm install jest --global
+WORKDIR /cpr
+COPY __test__/entrypoint.sh /entrypoint.sh
+ENTRYPOINT ["/entrypoint.sh"]
+EOF
+
+    docker build -t $IMAGE .
+    rm Dockerfile
+fi
+
+docker run -v $PWD:/cpr $IMAGE