message: Add instruction for testing hadoop
diff: @@ -34,6 +34,24 @@ cc_library(
  ],
  )
  +# This test is set to manual because it requires downloading the Hadoop
  +# distribution to run. To run this test:
  +# 1. Ensure $JAVA_HOME is set to the location of a JDK 8 installation.
  +# 2. Download the binary Hadoop distribution from:
  +# http://hadoop.apache.org/releases.html
  +# 3. Extract the Hadoop distribution and run:
  +# source libexec/hadoop-config.sh
  +# 4. Optionally set up HDFS cluster configurations (optionally Kerberos) within
  +# $HADOOP_HDFS_HOME/etc/hadoop if you want to test against real
  +# distributed HDFS cluster
  +# 5. bazel test \
  +# --test_env=LD_LIBRARY_PATH=$JAVA_HOME/jre/lib/amd64/server \
  +# --test_env=HADOOP_HDFS_HOME=$HADOOP_HDFS_HOME \
  +# --test_env=CLASSPATH=$($HADOOP_HDFS_HOME/bin/hadoop classpath --glob) \
  +# :hadoop_file_system_test
  +# To test against the real distributed cluster, add the following option for
  +# bazel test:
  +# --test_env=HADOOP_TEST_TMPDIR=hdfs://cluster/test/tmp/dir
  tf_cc_test(
  name = "hadoop_filesystem_test",
  srcs = [
  