GetServicePath should perform a scan

chrome/test/pyautolib/pyauto.py

Index: chrome/test/pyautolib/pyauto.py
diff --git a/chrome/test/pyautolib/pyauto.py b/chrome/test/pyautolib/pyauto.py
index 7ef8b953fed768b0f43e23ae388d4e24c10b4f56..50f13f3f605615260f6e6813e33b5a4c6d06d739 100755
--- a/chrome/test/pyautolib/pyauto.py
+++ b/chrome/test/pyautolib/pyauto.py
@@ -758,7 +758,7 @@ class PyUITest(pyautolib.PyUITestBase, unittest.TestCase):
     return PyUITest.EvalDataFrom(private_file)
 
   def WaitUntil(self, function, timeout=-1, retry_sleep=0.25, args=[],
-                expect_retval=None, debug=True):
+                expect_retval=None, keep_retval=False, debug=True):
     """Poll on a condition until timeout.
 
     Waits until the |function| evalues to |expect_retval| or until |timeout|
@@ -791,10 +791,14 @@ class PyUITest(pyautolib.PyUITestBase, unittest.TestCase):
                      exit criteria. In case this is None (the default),
                      |function|'s return value is checked for truth,
                      so 'non-empty-string' should match with True
+      keep_retval: Boolean indicating whether to return the retval of the last
+                   iteration of |function| that succeeded without a timeout, or
+                   True.
       debug: if True, displays debug info at each retry.
 
     Returns:
-      True, if returning when |function| evaluated to True
+      The return value of the calling function when |function| evaluates to True
+          and the keep_retval is True, or True when keep_retval is false.
       False, when returning due to timeout
     """
     if timeout == -1:  # Default
@@ -804,8 +808,9 @@ class PyUITest(pyautolib.PyUITestBase, unittest.TestCase):
     debug_begin = begin
     while timeout is None or time.time() - begin <= timeout:
       retval = function(*args)
-      if (expect_retval is None and retval) or expect_retval == retval:
-        return True
+      if (expect_retval is None and retval) or \
+         (expect_retval is not None and expect_retval == retval):
+        return {True: retval, False: True}[keep_retval]

[Nirnimesh, 2012/08/08 19:51:13]

I think it'll be fine if you just return retval here (ie don't add the option in
line 761). The truth value still evaluates to True, so users will continue to
work

[stanleyw, 2012/08/08 21:38:35]

Done.

       if debug and time.time() - debug_begin > 5:
         debug_begin += 5
         if function.func_name == (lambda: True).func_name:
@@ -5178,21 +5183,34 @@ class PyUITest(pyautolib.PyUITestBase, unittest.TestCase):
        connected_service_path in service_list['wifi_networks']:
        return service_list['wifi_networks'][connected_service_path]['name']
 
-  def GetServicePath(self, ssid):
-    """Returns the service path associated with an SSID.
+  def GetServicePath(self, ssid, encryption=None, timeout=30):
+    """Waits until the SSID is observed and returns its service path.
 
     Args:
       ssid: String defining the SSID we are searching for.
+      encryption: Encryption type of the network; either None to return the
+                  first instance of network that matches the ssid, '' for
+                  an empty network, 'PSK', 'WEP' or '8021X'.
+      timeout: Duration to wait for ssid to appear.
 
     Returns:
-      The service path or None if SSID does not exist.
-    """
-    service_list = self.GetNetworkInfo()
-    service_list = service_list.get('wifi_networks', [])
-    for service_path, service_obj in service_list.iteritems():
-      if service_obj['name'] == ssid:
-        return service_path
-    return None
+      The service path or None if SSID does not exist after timeout period.
+    """
+    def _get_service_path():
+      service_list = self.GetNetworkInfo().get('wifi_networks', [])
+      for service_path, service_obj in service_list.iteritems():
+        service_encr = 'PSK' if service_obj['encryption'] in ['WPA', 'RSN'] \
+                       else service_obj['encryption']
+
+        if service_obj['name'] == ssid and \
+           (encryption == None or service_encr == encryption):
+          return service_path
+      self.NetworkScan()
+      return None
+
+    service_path = self.WaitUntil(_get_service_path, keep_retval=True,
+                                  timeout=timeout, retry_sleep=1)
+    return service_path or None
 
   def NetworkScan(self):
     """Causes ChromeOS to scan for available wifi networks.