Splitting out bundle install for ruby into the prebuild step.

tools/run_tests/build_ruby.sh

@@ -37,6 +37,4 @@ export GRPC_CONFIG=${CONFIG:-opt}
 cd $(dirname $0)/../../src/ruby
 
 rm -rf ./tmp
-
-bundle install
 rake compile:grpc

tools/run_tests/pre_build_ruby.sh

@@ -0,0 +1,39 @@
+#!/bin/bash
+
+# Copyright 2015, Google Inc.
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+# * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+# * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+# * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+set -ex
+
+export GRPC_CONFIG=${CONFIG:-opt}
+
+# change to grpc's ruby directory
+cd $(dirname $0)/../../src/ruby
+
+bundle install

tools/run_tests/run_tests.py

@@ -284,7 +284,7 @@ def test_specs(self, config, travis):
  environ=_FORCE_ENVIRON_FOR_WRAPPERS)]
 
  def pre_build_steps(self):
- return []
+ return [['tools/run_tests/pre_build_ruby.sh']]
 
  def make_targets(self):
  return ['static_c']