Adds the ability to run pure Go unit tests in the Mojo test suite.

mojo/tools/mopy/invoke_go.py

Index: mojo/tools/mopy/invoke_go.py
diff --git a/mojo/tools/mopy/invoke_go.py b/mojo/tools/mopy/invoke_go.py
new file mode 100644
index 0000000000000000000000000000000000000000..366e2d4e8f553145368fa299abe16638fd3dc9e5
--- /dev/null
+++ b/mojo/tools/mopy/invoke_go.py
@@ -0,0 +1,106 @@
+# Copyright 2015 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+"""The function InvokeGo() is used to invoke the Go tool after setting up
+the environment and current working directory."""
+
+import os
+import subprocess
+import sys
+
+NDK_PLATFORM = 'android-16'
+NDK_TOOLCHAIN = 'arm-linux-androideabi-4.9'
+
+def InvokeGo(go_tool, go_options, work_dir=None, src_root=None,
+             out_root=None, cgo_cflags=None, cgo_ldflags=None,
+             target_android=False):
+  """ Invokes the go tool after setting up the environment.
+  go_tool     The path to the 'go' binary. Must be either an absolute path
+              or a path relative to the current working directory.
+
+  go_options  A list of string arguments that will be passed to 'go'
+
+  work_dir    Optional specification of a directory to temporarily switch into
+              before invoking the go tool. If set it must be a path relative to
+              the current working directory or an absolute path.
+
+  src_root    Optional specification of the Mojo src root. If set it must be
+              a path relative to the current working directory or an absolute
+              path. This will be used to add additional elements to
+              the GOPATH environment variable.
+
+  out_root    Optional specification of the Mojo out dir. If set it must be
+              a path relative to the current working directory or an absolute
+              path. This will be used to add additional elements to
+              the GOPATH environment variable.
+
+  cgo_cflags  Optional value to set for the CGO_CFLAGS environment variable.
+
+  cgo_ldflags Optional value to set for the CGO_LDFLAGS environment variable.
+
+  target_android
+               Set to true to target Android.
+  """
+  go_tool = os.path.abspath(go_tool)
+  env = os.environ.copy()
+  env['GOROOT'] = os.path.dirname(os.path.dirname(go_tool))
+
+  go_path = ''
+  if src_root is not None:
+    # The src directory specified may be relative.
+    src_root = os.path.abspath(src_root)
+    # GOPATH must be absolute, and point to one directory up from |src_Root|
+    go_path = os.path.abspath(os.path.join(src_root, '..'))
+    # GOPATH also includes any third_party/go libraries that have been imported
+    go_path += ':' +  os.path.join(src_root, 'third_party', 'go')
+
+  if out_root is not None:
+    go_path += ':' +  os.path.abspath(os.path.join(out_root, 'gen', 'go'))
+
+  if 'MOJO_GOPATH' in os.environ:
+      go_path += ':' + os.environ['MOJO_GOPATH']
+
+  if len(go_path) > 0 :
+    env['GOPATH'] = go_path
+
+  if cgo_cflags is not None:
+    env['CGO_CFLAGS'] = cgo_cflags
+
+  if cgo_ldflags is not None:
+    env['CGO_LDFLAGS'] = cgo_ldflags
+
+  if target_android:
+    env['CGO_ENABLED'] = '1'
+    env['GOOS'] = 'android'
+    env['GOARCH'] = 'arm'
+    env['GOARM'] = '7'
+    # The Android go tool prebuilt binary has a default path to the compiler,
+    # which with high probability points to an invalid path, so we override the
+    # CC env var that will be used by the go tool.
+    if 'CC' not in env:
+      if src_root is None:
+        raise Exception('src_root must be set if is_android is true and '
+                        '"CC" is not in env.')
+      # Note that src_root was made absolute above.
+      ndk_path = os.path.join(src_root, 'third_party', 'android_tools', 'ndk')
+      if sys.platform.startswith('linux'):
+        arch = 'linux-x86_64'
+      elif sys.platform == 'darwin':
+        arch = 'darwin-x86_64'
+      else:
+        raise Exception('unsupported platform: ' + sys.platform)
+      ndk_cc = os.path.join(ndk_path, 'toolchains', NDK_TOOLCHAIN,
+          'prebuilt', arch, 'bin', 'arm-linux-androideabi-gcc')
+      sysroot = os.path.join(ndk_path, 'platforms', NDK_PLATFORM, 'arch-arm')
+      env['CGO_CFLAGS'] += ' --sysroot %s' % sysroot
+      env['CGO_LDFLAGS'] += ' --sysroot %s' % sysroot
+      env['CC'] = '%s --sysroot %s' % (ndk_cc, sysroot)
+
+  save_cwd = os.getcwd()
+  if work_dir is not None:
+    os.chdir(work_dir)
+  result = subprocess.call([go_tool] + go_options, env=env)
+  if work_dir is not None:
+    os.chdir(save_cwd)
+  return result