--- a/testing/firefox-ui/tests/functional/keyboard_shortcuts/test_browser_window.py
+++ b/testing/firefox-ui/tests/functional/keyboard_shortcuts/test_browser_window.py
@@ -32,17 +32,17 @@ class TestBrowserWindowShortcuts(Puppete
         current_name = self.marionette.execute_script("""
             return window.document.activeElement.localName;
         """)
 
         # This doesn't test anything if we're already at input.
         self.assertNotEqual(current_name, "input")
 
         # TODO: To be moved to the upcoming search library
-        if self.puppeteer.platform == 'linux':
+        if self.marionette.session_capabilities['platformName'] == 'linux':
             key = 'searchFocusUnix.commandkey'
         else:
             key = 'searchFocus.commandkey'
         self.browser.send_shortcut(self.browser.localize_entity(key),
                                    accel=True)
 
         # TODO: Check that the right input box is focused
         # Located below searchbar as class="autocomplete-textbox textbox-input"

--- a/testing/firefox-ui/tests/puppeteer/test_page_info_window.py
+++ b/testing/firefox-ui/tests/puppeteer/test_page_info_window.py
@@ -63,18 +63,19 @@ class TestPageInfoWindow(PuppeteerMixin,
         def opener(win):
             self.browser.menubar.select_by_id('tools-menu', 'menu_pageInfo')
 
         open_strategies = ('menu',
                            'shortcut',
                            opener,
                            )
 
+        platformName = self.marionette.session_capabilities['platformName']
         for trigger in open_strategies:
-            if trigger == 'shortcut' and self.puppeteer.platform == 'windows_nt':
+            if trigger == 'shortcut' and platformName == 'windows_nt':
                 # The shortcut for page info window does not exist on windows.
                 self.assertRaises(ValueError, self.browser.open_page_info_window,
                                   trigger=trigger)
                 continue
 
             page_info = self.browser.open_page_info_window(trigger=trigger)
             self.assertEquals(page_info, self.puppeteer.windows.current)
             page_info.close()
@@ -85,16 +86,17 @@ class TestPageInfoWindow(PuppeteerMixin,
             win.send_shortcut(win.localize_entity('closeWindow.key'),
                               accel=True)
 
         # Close a tab by each trigger method
         close_strategies = ('menu',
                             'shortcut',
                             closer,
                             )
+        platformName = self.marionette.session_capabilities['platformName']
         for trigger in close_strategies:
             # menu only works on OS X
-            if trigger == 'menu' and self.puppeteer.platform != 'darwin':
+            if trigger == 'menu' and platformName != 'darwin':
                 continue
 
             page_info = self.browser.open_page_info_window()
             page_info.close(trigger=trigger)
             self.assertTrue(page_info.closed)

--- a/testing/marionette/puppeteer/firefox/firefox_puppeteer/puppeteer.py
+++ b/testing/marionette/puppeteer/firefox/firefox_puppeteer/puppeteer.py
@@ -45,24 +45,16 @@ class Puppeteer(object):
 
     @use_class_as_property('api.utils.Utils')
     def utils(self):
         """Provides an api for interacting with utility actions.
 
         See the :class:`~api.utils.Utils` reference.
         """
 
-    @property
-    def platform(self):
-        """Returns the lowercased platform name.
-
-        :returns: Platform name
-        """
-        return self.marionette.session_capabilities['platformName']
-
     @use_class_as_property('api.prefs.Preferences')
     def prefs(self):
         """
         Provides an api for setting and inspecting preferences, as see in
         about:config.
 
         See the :class:`~api.prefs.Preferences` reference.
         """