diff --git a/vdirsyncer/storage/filesystem.py b/vdirsyncer/storage/filesystem.py
index 5b0a927..22b8d44 100644
--- a/vdirsyncer/storage/filesystem.py
+++ b/vdirsyncer/storage/filesystem.py
@@ -47,9 +47,9 @@ class FilesystemStorage(Storage):
         return os.path.getmtime(fpath)
 
     def update(self, obj, etag):
-        fpath = self._get_filepath(obj)
+        fpath = self._get_filepath(obj.uid)
         if not os.path.exists(fpath):
-            raise exceptions.NotFoundError(href)
+            raise exceptions.NotFoundError(obj.uid)
         actual_etag = os.path.getmtime(fpath)
         if etag != actual_etag:
             raise exceptions.WrongEtagError(etag, actual_etag)
@@ -60,6 +60,9 @@ class FilesystemStorage(Storage):
 
     def delete(self, uid, etag):
         fpath = self._get_filepath(uid)
-        if etag != os.path.getmtime(fpath):
+        if not os.path.isfile(fpath):
+            raise exceptions.NotFoundError(uid)
+        actual_etag = os.path.getmtime(fpath)
+        if etag != actual_etag:
             raise exceptions.WrongEtagError(etag, actual_etag)
         os.remove(fpath)
diff --git a/vdirsyncer/tests/test_storage.py b/vdirsyncer/tests/test_storage.py
index 3993139..305f12b 100644
--- a/vdirsyncer/tests/test_storage.py
+++ b/vdirsyncer/tests/test_storage.py
@@ -15,6 +15,7 @@ import shutil
 from vdirsyncer.storage.base import Item
 from vdirsyncer.storage.filesystem import FilesystemStorage
 from vdirsyncer.storage.memory import MemoryStorage
+import vdirsyncer.exceptions as exceptions
 
 class StorageTests(object):
     def _get_storage(self, **kwargs):
@@ -44,6 +45,28 @@ class StorageTests(object):
             item, etag = s.get(i)
             assert item.raw == 'UID:{}'.format(i)
 
+    def test_upload_already_existing(self):
+        s = self._get_storage()
+        item = Item('UID:1')
+        s.upload(item)
+        self.assertRaises(exceptions.AlreadyExistingError, s.upload, item)
+
+    def test_update_nonexisting(self):
+        s = self._get_storage()
+        item = Item('UID:1')
+        self.assertRaises(exceptions.NotFoundError, s.update, item, 123)
+
+    def test_wrong_etag(self):
+        s = self._get_storage()
+        item = Item('UID:1')
+        etag = s.upload(item)
+        self.assertRaises(exceptions.WrongEtagError, s.update, item, 'lolnope')
+        self.assertRaises(exceptions.WrongEtagError, s.delete, '1', 'lolnope')
+
+    def test_delete_nonexisting(self):
+        s = self._get_storage()
+        self.assertRaises(exceptions.NotFoundError, s.delete, '1', 123)
+
 
 class FilesystemStorageTests(TestCase, StorageTests):
     tmpdir = None