Add testcases for file.truncate(), and fix some failing FS implementations

1 files changed, 5 insertions, 2 deletions

diff --git a/fs/wrapfs/limitsizefs.py b/fs/wrapfs/limitsizefs.py
index 6fa40fd..01616c6 100644
--- a/fs/wrapfs/limitsizefs.py
+++ b/fs/wrapfs/limitsizefs.py
@@ -61,7 +61,7 @@ class LimitSizeFS(WrapFS):
                 self._file_sizes[path] = 0
             return LimitSizeFile(self,path,f,mode,size)
 
-    def _ensure_file_size(self, path, size):
+    def _ensure_file_size(self, path, size, shrink=False):
         path = relpath(normpath(path))
         with self._size_lock:
             if path not in self._file_sizes:
@@ -73,6 +73,9 @@ class LimitSizeFS(WrapFS):
                     raise StorageSpaceError("write")
                 self.cur_size += diff
                 self._file_sizes[path] = size
+            elif diff < 0 and shrink:
+                self.cur_size += diff
+                self._file_sizes[path] = size
 
     def copy(self, src, dst, **kwds):
         FS.copy(self,src,dst,**kwds)
@@ -141,7 +144,7 @@ class LimitSizeFile(object):
         pos = self.file.tell()
         if size is None:
             size = pos
-        self.fs._ensure_file_size(self.path,size)
+        self.fs._ensure_file_size(self.path,size,shrink=True)
         self.file.truncate(size)
         self.size = size