Velocity Mocha in Docker cannot run client tests

I have built a docker image for meteor based on official ubuntu:latest image, but mocha client side unit test cannot start on it. The same project tests well on Mac OS X dev machine and Ubuntu 14.04 host server. How can I fix it?

"meteor run --test " stuck at beginning of client tests, to visit the web site with browser shows same result, the server side tests are executed, the client side tests are founded but not executed.

I have compared the VELOCITY_DEBUG log, there is no obvious difference than working environment.

The Dockerfile is simple:

FROM ubuntu:latest
MAINTAINER "Wu Yang <pinxue@gmail.com>"

# git is not required indeed, but as all the images planed to derive from will need it, here is the best place for it.
RUN apt-get update && apt-get install -y curl git
# Install latest node.js
RUN curl -sL https://deb.nodesource.com/setup | sudo bash - && apt-get install -y nodejs
# Install build-essential, it is required if building native node.js module
RUN apt-get install -y build-essential && apt-get clean

# Setup user
RUN useradd -ms /bin/bash www && \
    chown -R www:www /usr/local && \
    chown -R www:www /usr/lib/node_modules && \
    echo "ALL ALL = (ALL) NOPASSWD: ALL" >> /etc/sudoers

WORKDIR /home/www
ENV HOME /home/www
USER www

# Install meteor
RUN curl https://install.meteor.com/ | sudo sh