some enhancements

fs/fs.py

@@ -335,7 +335,22 @@ class FS(object):
             return "OS file, maps to %s" % sys_path
 
     def open(self, path, mode="r", **kwargs):
-        raise UNSUPPORTED_ERROR("UNSUPPORTED")
+        raise UnsupportedError("UNSUPPORTED")
+
+    def getcontents(self, path):
+        """Returns the contents of a file as a string.
+
+        path -- path of file to read.
+
+        """
+        f = None
+        try:
+            f = self.open(path, "rb")
+            contents = f.read()
+            return contents
+        finally:
+            if f is not None:
+                f.close()
 
     def opendir(self, path):
         if not self.exists(path):

fs/tests.py

@@ -405,6 +405,7 @@ class TestOSFS(unittest.TestCase):
         word = f7.read(7)
         self.assertEqual(word, "complex")
         f7.close()
+        self.assertEqual(self.fs.getcontents("a.txt"), all_strings)
 
 
 class TestSubFS(TestOSFS):