foo.diff

diff --git a/django/contrib/staticfiles/finders.py b/django/contrib/staticfiles/finders.py
index eede6fb..eed88a0 100644
--- a/django/contrib/staticfiles/finders.py
+++ b/django/contrib/staticfiles/finders.py
@@ -57,7 +57,7 @@ class FileSystemFinder(BaseFinder):
                 prefix, root = root
             else:
                 prefix = ''
-            if os.path.abspath(settings.STATIC_ROOT) == os.path.abspath(root):
+            if settings.STATIC_ROOT and os.path.abspath(settings.STATIC_ROOT) == os.path.abspath(root):
                 raise ImproperlyConfigured(
                     "The STATICFILES_DIRS setting should "
                     "not contain the STATIC_ROOT setting")
diff --git a/django/contrib/staticfiles/storage.py b/django/contrib/staticfiles/storage.py
index b5d05aa..d7ddefc 100644
--- a/django/contrib/staticfiles/storage.py
+++ b/django/contrib/staticfiles/storage.py
@@ -32,14 +32,18 @@ class StaticFilesStorage(FileSystemStorage):
             location = settings.STATIC_ROOT
         if base_url is None:
             base_url = settings.STATIC_URL
-        if not location:
-            raise ImproperlyConfigured("You're using the staticfiles app "
-                                       "without having set the STATIC_ROOT "
-                                       "setting to a filesystem path.")
         check_settings(base_url)
         super(StaticFilesStorage, self).__init__(location, base_url,
                                                  *args, **kwargs)
+        if location is None:
+            self.location = None
 
+    def path(self, name):
+        if not self.location:
+            raise ImproperlyConfigured("You're using the staticfiles app "
+                                       "without having set the STATIC_ROOT "
+                                       "setting to a filesystem path.")
+        return super(StaticFilesStorage, self).path(name)
 
 class CachedFilesMixin(object):
     default_template = """url("%s")"""