Return partial output when shell.run_and_get_output time limit is hit.

mojo/devtools/common/devtoolslib/linux_shell_unittest.py

Index: mojo/devtools/common/devtoolslib/linux_shell_unittest.py
diff --git a/mojo/devtools/common/devtoolslib/linux_shell_unittest.py b/mojo/devtools/common/devtoolslib/linux_shell_unittest.py
new file mode 100644
index 0000000000000000000000000000000000000000..6a70848205ae62e35d63a469b2da5d2a028ae6b7
--- /dev/null
+++ b/mojo/devtools/common/devtoolslib/linux_shell_unittest.py
@@ -0,0 +1,93 @@
+# 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.
+
+"""Tests for the linux shell abstraction."""
+
+import imp
+import os.path
+import sys
+import unittest
+import tempfile
+import shutil
+import threading
+
+try:
+  imp.find_module("devtoolslib")
+except ImportError:
+  sys.path.append(os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
+
+from devtoolslib.linux_shell import LinuxShell
+
+
+class LinuxShellTest(unittest.TestCase):
+  """Tests the Linux shell abstraction.
+
+  These do not actually run the shell binary, it is substituted for shell utils
+  like sleep or cat.
+  """
+
+  def test_run_and_get_output(self):
+    """Verifies that run_and_get_output() correctly builds and passes the
+    argument list to the binary.
+    """
+    shell = LinuxShell('echo')
+    shell_args = ['--some-argument 42', 'unicornA', 'unicornB']
+    return_code, output, did_time_out = shell.run_and_get_output(shell_args)
+
+    self.assertEquals(0, return_code)
+    self.assertEquals(' '.join(shell_args), output.strip())
+    self.assertEquals(False, did_time_out)
+
+  def test_run_and_get_output_timeout_met(self):
+    """Verifies the returned values of run_and_get_output() when timeout is set
+    but the binary exits before it is hit.
+    """
+    shell = LinuxShell('echo')
+    shell_args = ['--some-argument 42', 'unicornA', 'unicornB']
+    return_code, output, did_time_out = shell.run_and_get_output(shell_args,
+                                                                 timeout=1)
+
+    self.assertEquals(0, return_code)
+    self.assertEquals(' '.join(shell_args), output.strip())
+    self.assertEquals(False, did_time_out)
+
+  def test_run_and_get_output_timeout_exceeded(self):
+    """Verifies the returned values of run_and_get_output() when timeout is set
+    and the binary does not exit before it is hit.
+    """
+    temp_dir = tempfile.mkdtemp()
+    fifo_path = os.path.join(temp_dir, 'fifo')
+    os.mkfifo(fifo_path)
+
+    class Data:
+      fifo = None
+
+    # Any write to the fifo will block until it is open for reading by cat,
+    # hence write on a background thread.
+    def _write_to_fifo():
+      Data.fifo = open(fifo_path, 'w')
+      print >> Data.fifo, 'abc'
+      Data.fifo.flush()
+    write_thread = threading.Thread(target=_write_to_fifo)
+    write_thread.start()
+
+    # The call to cat should read what is written to the fifo ('abc') and then
+    # stall forever, as we don't close the fifo after writing.
+    shell = LinuxShell('cat')
+    args = [fifo_path]
+    _, output, did_time_out = shell.run_and_get_output(args, timeout=1)
+
+    write_thread.join()
+    if Data.fifo:
+      Data.fifo.close()
+
+    # Verify that the process did time out and that the output was correctly
+    # produced before that.
+    self.assertEquals(True, did_time_out)
+    self.assertEquals('abc', output.strip())
+    shutil.rmtree(temp_dir)
+
+
+if __name__ == "__main__":
+  unittest.main()