keystone: test cases, refactoring and cleanup

Dockerfile

@@ -11,12 +11,15 @@ FROM alpine:3.8
 # experience when this doesn't work out of the box.
 #
 # OpenSSL is required so wget can query HTTPS endpoints for health checking.
-RUN apk add --update ca-certificates openssl bash
+RUN apk add --update ca-certificates openssl
+
+COPY --from=0 /go/bin/dex /usr/local/bin/dex
 
 # Import frontend assets and set the correct CWD directory so the assets
 # are in the default path.
 COPY web /web
 WORKDIR /
 
-EXPOSE 5500-5600
-CMD ["bash"]
+ENTRYPOINT ["dex"]
+
+CMD ["version"]