added appendtext and appendbytes

fs/base.py

@@ -194,6 +194,42 @@ def setinfo(self, path, info):
     # Filesystems *may* implement these methods.                       #
     # ---------------------------------------------------------------- #
 
+    def appendbytes(self, path, data):
+        """
+        Append bytes to the end of a file. Creating the file if it
+        doesn't already exists.
+
+        :param str path: Path to a file.
+        :param bytes data: Bytes to append.
+        :raises: :class:`ValueError` if ``data`` is not bytes.
+        :raises: :class:`fs.errors.ResourceNotFound` if a parent
+            directory of ``path`` does not exist.
+
+        """
+        if not isinstance(data, bytes):
+            raise ValueError('must be bytes')
+        with self._lock:
+            with self.open(path, 'ab') as append_file:
+                append_file.write(data)
+
+    def appendtext(self, path, text):
+        """
+        Append text to a file. Creating the file if it doesn't already
+        exists.
+
+        :param str path: Path to a file.
+        :param str text: Text to append.
+        :raises: :class:`ValueError` if ``text`` is not bytes.
+        :raises: :class:`fs.errors.ResourceNotFound` if a parent
+            directory of ``path`` does not exist.
+
+        """
+        if not isinstance(text, six.text_type):
+            raise ValueError('must be unicode str')
+        with self._lock:
+            with self.open(path, 'at') as append_file:
+                append_file.write(text)
+
     def close(self):
         """
         Close the filesystem and release any resources.
@@ -641,9 +677,7 @@ def isempty(self, path):
         :rtype: bool
 
         """
-        for info in self.scandir(path):
-            return False
-        return True
+        return next(iter(self.scandir(path)), None) is None
 
     def isfile(self, path):
         """Check a path exists and is a file."""

fs/mode.py

@@ -111,7 +111,7 @@ def validate_bin(self):
     @property
     def create(self):
         """Check if the mode would create a file."""
-        return 'w' in self or 'x' in self
+        return 'a' in self or 'w' in self or 'x' in self
 
     @property
     def reading(self):

fs/wrapfs.py

@@ -204,13 +204,13 @@ def filterdir(self,
         self.check()
         _fs, _path = self.delegate_path(path)
         iter_files = iter(_fs.filterdir(
-           _path,
-           exclude_dirs=exclude_dirs,
-           exclude_files=exclude_files,
-           files=files,
-           dirs=dirs,
-           namespaces=namespaces,
-           page=page
+            _path,
+            exclude_dirs=exclude_dirs,
+            exclude_files=exclude_files,
+            files=files,
+            dirs=dirs,
+            namespaces=namespaces,
+            page=page
         ))
         with unwrap_errors(path):
             for info in iter_files:

tests/test_fs.py

@@ -285,6 +285,19 @@ def assert_text(self, path, contents):
         self.assertEqual(data, contents)
         self.assertIsInstance(data, text_type)
 
+
+    def test_appendbytes(self):
+        with self.assertRaises(ValueError):
+            self.fs.appendbytes('foo', 'bar')
+        self.fs.appendbytes('foo', b'bar')
+        self.assert_bytes('foo', b'bar')
+
+    def test_appendtext(self):
+        with self.assertRaises(ValueError):
+            self.fs.appendtext('foo', b'bar')
+        self.fs.appendtext('foo', 'bar')
+        self.assert_text('foo', 'bar')
+
     def test_basic(self):
         # Check str and repr don't break
         repr(self.fs)