Clean the machine before running commands in the mini_installer test framework.

chrome/test/mini_installer/test_installer.py

Index: chrome/test/mini_installer/test_installer.py
diff --git a/chrome/test/mini_installer/test_installer.py b/chrome/test/mini_installer/test_installer.py
index e0614243b0ee51d3c5219d77e050f43e494f4bb3..a1ca4be38539334ff1b0263b28fae573fcc01220 100644
--- a/chrome/test/mini_installer/test_installer.py
+++ b/chrome/test/mini_installer/test_installer.py
@@ -69,7 +69,7 @@ class InstallerTest(unittest.TestCase):
     self.assertEqual(1, len(self._test) % 2,
                      'The length of test array must be odd')
 
-    # TODO(sukolsak): run a reset command that puts the machine in clean state.
+    self._RunCleanCommand()
 
     state = self._test[0]
     self._VerifyState(state)
@@ -118,6 +118,19 @@ class InstallerTest(unittest.TestCase):
       self.fail('Command %s returned non-zero exit status %s' % (
           resolved_command, exit_status))
 
+  def _RunCleanCommand(self):
+    """Puts the machine in the clean state (i.e. Chrome not installed)."""
+    # TODO(sukolsak): Read the clean state from the config file and clean
+    # the machine according to it.

[robertshield, 2013/09/10 20:59:31]

Also, consider adding a TODO to handle SxS installs (what canary does).

[sukolsak, 2013/09/10 21:26:29]

Done.

+    command = ('python uninstall_chrome.py '
+               '--chrome-long-name="$CHROME_LONG_NAME" & '

[robertshield, 2013/09/10 20:59:31]

Just to double check: it is my understanding that if either of these fail, then
they will print an informative error message to stdout or stderr. Is that
correct?

[sukolsak, 2013/09/10 21:26:29]

They will print an error message to stderr. For example, if Chrome is not
installed, they will complain that they can't find the registry key for the
uninstall command. The error message is not really useful because our goal is to
remove everything. We just give the uninstaller a chance to do a preliminary
cleanup before we do it ourselves.

+               'python uninstall_chrome.py '
+               '--chrome-long-name="$CHROME_LONG_NAME" --system-level')
+    resolved_command = self._path_resolver.ResolvePath(command)
+    script_dir = os.path.dirname(os.path.abspath(__file__))
+    subprocess.call(resolved_command, shell=True, cwd=script_dir,
+                    stderr=open(os.devnull, 'w'))
+
 
 def MergePropertyDictionaries(current_property, new_property):
   """Merges the new property dictionary into the current property dictionary.