RunCommand was catching and rethrowing an exception, which seemed to generate

lib/cros_build_lib_unittest.py

Index: lib/cros_build_lib_unittest.py
diff --git a/lib/cros_build_lib_unittest.py b/lib/cros_build_lib_unittest.py
new file mode 100755
index 0000000000000000000000000000000000000000..a66424b8148c22f73b3a36f7f174bea7053b4002
--- /dev/null
+++ b/lib/cros_build_lib_unittest.py
@@ -0,0 +1,76 @@
+#!/usr/bin/python
+#
+# Copyright (c) 2011 The Chromium OS Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+"""Unit tests for cros_build_lib."""
+
+import unittest
+
+import cros_build_lib
+
+class CrosBuildLibTest(unittest.TestCase):
+  """Test class for cros_build_lib."""
+
+  def testRunCommandSimple(self):
+    """Test that RunCommand can run a simple successful command."""
+    result = cros_build_lib.RunCommand(['ls'],
+                                       # Keep the test quiet options
+                                       print_cmd=False,
+                                       redirect_stdout=True,
+                                       redirect_stderr=True,
+                                       # Test specific options
+                                       exit_code=True)
+    self.assertEqual(result, 0)
+
+  def testRunCommandError(self):
+    """Test that RunCommand can return an error code for a failed command."""
+    result = cros_build_lib.RunCommand(['ls', '/nosuchdir'],
+                                       # Keep the test quiet options
+                                       print_cmd=False,
+                                       redirect_stdout=True,
+                                       redirect_stderr=True,
+                                       # Test specific options
+                                       error_ok=True,
+                                       exit_code=True)
+    self.assertNotEqual(result, 0)
+
+  def testRunCommandErrorRetries(self):
+    """Test that RunCommand can retry a failed command that always fails."""
+
+    # We don't actually check that it's retrying, just exercise the code path. 
+    result = cros_build_lib.RunCommand(['ls', '/nosuchdir'],
+                                       # Keep the test quiet options
+                                       print_cmd=False,
+                                       redirect_stdout=True,
+                                       redirect_stderr=True,
+                                       # Test specific options
+                                       num_retries=2,
+                                       error_ok=True,
+                                       exit_code=True)
+    self.assertNotEqual(result, 0)
+
+  def testRunCommandErrorException(self):
+    """Test that RunCommand can throw an exception when a command fails."""
+
+    function = lambda : cros_build_lib.RunCommand(['ls', '/nosuchdir'],
+                                                  # Keep the test quiet options
+                                                  print_cmd=False,
+                                                  redirect_stdout=True,
+                                                  redirect_stderr=True) 
+    self.assertRaises(cros_build_lib.RunCommandException, function)
+
+  def testRunCommandCaptureOutput(self):
+    """Test that RunCommand can capture stdout if a command succeeds."""
+    
+    result = cros_build_lib.RunCommand(['echo', '-n', 'Hi'],
+                                       # Keep the test quiet options
+                                       print_cmd=False,
+                                       redirect_stdout=True,
+                                       redirect_stderr=True)
+    self.assertEqual(result, 'Hi')
+
+
+if __name__ == '__main__':
+  unittest.main()